Dermatopathology

As employers search for ways to reduce the cost of providing health care to their employees, there is a growing trend toward narrowed provider networks and exclusive laboratory contracts. In the case of clinical pathology, some of these choices make sense from the employer’s perspective. A complete blood cell count or comprehensive metabolic panel is done on a machine and the result is much the same regardless of the laboratory. So why not have all laboratory tests performed by the lowest bidder?

Laboratories vary in quality and anatomic pathology services are different from blood tests. Each slide must be interpreted by a physician and skill in the interpretation of skin specimens varies widely. Dermatopathology was one of the first subspecialties to be recognized within pathology, as it requires a high level of expertise. Clinicopathological correlation often is key to the accurate interpretation of a specimen. The stakes are high, and a delay in diagnosis of melanoma remains one of the most serious errors in medicine and one of the most common causes for litigation in dermatology.

The accurate interpretation of skin biopsy specimens becomes especially difficult when inadequate or misleading clinical information accompanies the specimen. A study of 589 biopsies submitted by primary care physicians and reported by general pathologists demonstrated a 6.5% error rate. False-negative errors were the most common, but false-positives also were observed.¹ A study of pigmented lesions referred to the University of California, San Francisco, demonstrated a discordance rate of 14.3%.² The degree of discordance would be expected to vary based on the range of diagnoses included in each study.

Board-certified dermatopathologists have varying areas of expertise and there is notable subjectivity in the interpretation of biopsy specimens. In the case of problematic pigmented lesions such as atypical Spitz nevi, there can be low interobserver agreement even among the experts in categorizing lesions as malignant versus nonmalignant (κ=0.30).³ The low concordance among expert dermatopathologists demonstrates that light microscopic features alone often are inadequate for diagnosis. Advanced studies, including immunohistochemical stains, can help to clarify the diagnosis. In the case of atypical Spitz tumors, the contribution of special stains to the final diagnosis is statistically similar to that of hematoxylin and eosin sections and age, suggesting that nothing alone is sufficiently reliable to establish a definitive diagnosis in every case.⁴ Although helpful, these studies are costly, and savings obtained by sending cases to the lowest bidder can evaporate quickly. Costs are higher when factoring in molecular studies, which can run upwards of $3000 per slide; the cost of litigation related to incorrect diagnoses; or the human costs of an incorrect diagnosis.

As a group, dermatopathologists are highly skilled in the interpretation of skin specimens, but challenging lesions are common in the routine practice of dermatopathology. A study of 1249 pigmented melanocytic lesions demonstrated substantial agreement among expert dermatopathologists for less problematic lesions, though agreement was greater for patients 40 years and older (κ=0.67) than for younger patients (κ=0.49). Agreement was lower for patients with atypical mole syndrome (κ=0.31).⁵ These discrepancies occur despite the fact that there is good interobserver reproducibility for grading of individual histological features such as asymmetry, circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, symmetrical melanin, deep melanin, cytological atypia, mitoses, dermal lymphocytic infiltrate, and necrosis.⁶ These results indicate that accurate diagnoses cannot be reliably established simply by grading a list of histological features. Accurate diagnosis requires complex pattern recognition and integration of findings. Conflicting criteria often are present and an accurate interpretation requires considerable judgment as to which features are significant and which are not.

Separation of sebaceous adenoma, sebaceoma, and well-differentiated sebaceous carcinoma is another challenging area, and interobserver consensus can be as low as 11%,⁷ which suggests notable subjectivity in the criteria for diagnosis of nonmelanocytic tumors and emphasizes the importance of communication between the dermatopathologist and clinician when determining how to manage an ambiguous lesion. The interpretation of inflammatory skin diseases, alopecia, and lymphoid proliferations also can be problematic, and expert consultation often is required.

All dermatologists receive substantial training in dermatopathology, which puts them in an excellent position to interpret ambiguous findings in the context of the clinical presentation. Sometimes the dermatologist who has seen the clinical presentation can be in the best position to make the diagnosis. All clinicians must be wary of bias and an objective set of eyes often can be helpful. Communication is crucial to ensure appropriate care for each patient, and policies that restrict the choice of pathologist can be damaging.

As employers search for ways to reduce the cost of providing health care to their employees, there is a growing trend toward narrowed provider networks and exclusive laboratory contracts. In the case of clinical pathology, some of these choices make sense from the employer’s perspective. A complete blood cell count or comprehensive metabolic panel is done on a machine and the result is much the same regardless of the laboratory. So why not have all laboratory tests performed by the lowest bidder?

Laboratories vary in quality and anatomic pathology services are different from blood tests. Each slide must be interpreted by a physician and skill in the interpretation of skin specimens varies widely. Dermatopathology was one of the first subspecialties to be recognized within pathology, as it requires a high level of expertise. Clinicopathological correlation often is key to the accurate interpretation of a specimen. The stakes are high, and a delay in diagnosis of melanoma remains one of the most serious errors in medicine and one of the most common causes for litigation in dermatology.

The accurate interpretation of skin biopsy specimens becomes especially difficult when inadequate or misleading clinical information accompanies the specimen. A study of 589 biopsies submitted by primary care physicians and reported by general pathologists demonstrated a 6.5% error rate. False-negative errors were the most common, but false-positives also were observed.¹ A study of pigmented lesions referred to the University of California, San Francisco, demonstrated a discordance rate of 14.3%.² The degree of discordance would be expected to vary based on the range of diagnoses included in each study.

Board-certified dermatopathologists have varying areas of expertise and there is notable subjectivity in the interpretation of biopsy specimens. In the case of problematic pigmented lesions such as atypical Spitz nevi, there can be low interobserver agreement even among the experts in categorizing lesions as malignant versus nonmalignant (κ=0.30).³ The low concordance among expert dermatopathologists demonstrates that light microscopic features alone often are inadequate for diagnosis. Advanced studies, including immunohistochemical stains, can help to clarify the diagnosis. In the case of atypical Spitz tumors, the contribution of special stains to the final diagnosis is statistically similar to that of hematoxylin and eosin sections and age, suggesting that nothing alone is sufficiently reliable to establish a definitive diagnosis in every case.⁴ Although helpful, these studies are costly, and savings obtained by sending cases to the lowest bidder can evaporate quickly. Costs are higher when factoring in molecular studies, which can run upwards of $3000 per slide; the cost of litigation related to incorrect diagnoses; or the human costs of an incorrect diagnosis.

As a group, dermatopathologists are highly skilled in the interpretation of skin specimens, but challenging lesions are common in the routine practice of dermatopathology. A study of 1249 pigmented melanocytic lesions demonstrated substantial agreement among expert dermatopathologists for less problematic lesions, though agreement was greater for patients 40 years and older (κ=0.67) than for younger patients (κ=0.49). Agreement was lower for patients with atypical mole syndrome (κ=0.31).⁵ These discrepancies occur despite the fact that there is good interobserver reproducibility for grading of individual histological features such as asymmetry, circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, symmetrical melanin, deep melanin, cytological atypia, mitoses, dermal lymphocytic infiltrate, and necrosis.⁶ These results indicate that accurate diagnoses cannot be reliably established simply by grading a list of histological features. Accurate diagnosis requires complex pattern recognition and integration of findings. Conflicting criteria often are present and an accurate interpretation requires considerable judgment as to which features are significant and which are not.

Separation of sebaceous adenoma, sebaceoma, and well-differentiated sebaceous carcinoma is another challenging area, and interobserver consensus can be as low as 11%,⁷ which suggests notable subjectivity in the criteria for diagnosis of nonmelanocytic tumors and emphasizes the importance of communication between the dermatopathologist and clinician when determining how to manage an ambiguous lesion. The interpretation of inflammatory skin diseases, alopecia, and lymphoid proliferations also can be problematic, and expert consultation often is required.

All dermatologists receive substantial training in dermatopathology, which puts them in an excellent position to interpret ambiguous findings in the context of the clinical presentation. Sometimes the dermatologist who has seen the clinical presentation can be in the best position to make the diagnosis. All clinicians must be wary of bias and an objective set of eyes often can be helpful. Communication is crucial to ensure appropriate care for each patient, and policies that restrict the choice of pathologist can be damaging.

As employers search for ways to reduce the cost of providing health care to their employees, there is a growing trend toward narrowed provider networks and exclusive laboratory contracts. In the case of clinical pathology, some of these choices make sense from the employer’s perspective. A complete blood cell count or comprehensive metabolic panel is done on a machine and the result is much the same regardless of the laboratory. So why not have all laboratory tests performed by the lowest bidder?

Laboratories vary in quality and anatomic pathology services are different from blood tests. Each slide must be interpreted by a physician and skill in the interpretation of skin specimens varies widely. Dermatopathology was one of the first subspecialties to be recognized within pathology, as it requires a high level of expertise. Clinicopathological correlation often is key to the accurate interpretation of a specimen. The stakes are high, and a delay in diagnosis of melanoma remains one of the most serious errors in medicine and one of the most common causes for litigation in dermatology.

The accurate interpretation of skin biopsy specimens becomes especially difficult when inadequate or misleading clinical information accompanies the specimen. A study of 589 biopsies submitted by primary care physicians and reported by general pathologists demonstrated a 6.5% error rate. False-negative errors were the most common, but false-positives also were observed.¹ A study of pigmented lesions referred to the University of California, San Francisco, demonstrated a discordance rate of 14.3%.² The degree of discordance would be expected to vary based on the range of diagnoses included in each study.

Board-certified dermatopathologists have varying areas of expertise and there is notable subjectivity in the interpretation of biopsy specimens. In the case of problematic pigmented lesions such as atypical Spitz nevi, there can be low interobserver agreement even among the experts in categorizing lesions as malignant versus nonmalignant (κ=0.30).³ The low concordance among expert dermatopathologists demonstrates that light microscopic features alone often are inadequate for diagnosis. Advanced studies, including immunohistochemical stains, can help to clarify the diagnosis. In the case of atypical Spitz tumors, the contribution of special stains to the final diagnosis is statistically similar to that of hematoxylin and eosin sections and age, suggesting that nothing alone is sufficiently reliable to establish a definitive diagnosis in every case.⁴ Although helpful, these studies are costly, and savings obtained by sending cases to the lowest bidder can evaporate quickly. Costs are higher when factoring in molecular studies, which can run upwards of $3000 per slide; the cost of litigation related to incorrect diagnoses; or the human costs of an incorrect diagnosis.

As a group, dermatopathologists are highly skilled in the interpretation of skin specimens, but challenging lesions are common in the routine practice of dermatopathology. A study of 1249 pigmented melanocytic lesions demonstrated substantial agreement among expert dermatopathologists for less problematic lesions, though agreement was greater for patients 40 years and older (κ=0.67) than for younger patients (κ=0.49). Agreement was lower for patients with atypical mole syndrome (κ=0.31).⁵ These discrepancies occur despite the fact that there is good interobserver reproducibility for grading of individual histological features such as asymmetry, circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, symmetrical melanin, deep melanin, cytological atypia, mitoses, dermal lymphocytic infiltrate, and necrosis.⁶ These results indicate that accurate diagnoses cannot be reliably established simply by grading a list of histological features. Accurate diagnosis requires complex pattern recognition and integration of findings. Conflicting criteria often are present and an accurate interpretation requires considerable judgment as to which features are significant and which are not.

Separation of sebaceous adenoma, sebaceoma, and well-differentiated sebaceous carcinoma is another challenging area, and interobserver consensus can be as low as 11%,⁷ which suggests notable subjectivity in the criteria for diagnosis of nonmelanocytic tumors and emphasizes the importance of communication between the dermatopathologist and clinician when determining how to manage an ambiguous lesion. The interpretation of inflammatory skin diseases, alopecia, and lymphoid proliferations also can be problematic, and expert consultation often is required.

All dermatologists receive substantial training in dermatopathology, which puts them in an excellent position to interpret ambiguous findings in the context of the clinical presentation. Sometimes the dermatologist who has seen the clinical presentation can be in the best position to make the diagnosis. All clinicians must be wary of bias and an objective set of eyes often can be helpful. Communication is crucial to ensure appropriate care for each patient, and policies that restrict the choice of pathologist can be damaging.

The Diagnosis: Blaschkoid Graft-vs-host Disease

The patient had a history of myelodysplastic syndrome and underwent a bone marrow transplant 1 year prior to presentation. She had acute graft-vs-host disease (GVHD) 6 weeks following the transplant, which resolved with high-dose prednisone followed by UVB phototherapy. Skin biopsy demonstrated lichenoid dermatitis with vacuolar degeneration, dyskeratosis, and prominent pigment incontinence (Figure). Based on these findings and her clinical presentation, a diagnosis of blaschkoid GVHD was made.

Although acute GVHD is the result of immunocompetent donor T cells recognizing host tissues as foreign and initiating an immune response, the pathophysiology of chronic GVHD is not well understood.^1,2 Theories for disease pathogenesis in chronic GVHD suggest an underlying autoimmune and/or alloreactive process.^2-5 The skin often is the first organ affected in acute GVHD, and patients generally present with a pruritic morbilliform eruption that begins on the trunk and spreads to the rest of the body.^1,2 Cutaneous manifestations of chronic GVHD may be protean. Lesions can resemble systemic sclerosis or morphea, lichen planus, psoriasis, ichthyosis, and many other conditions.²

The differential diagnosis of linear dermatoses includes herpes zoster, contact dermatitis, lichen striatus (blaschkitis), nevus unius lateris, inflammatory linear verrucous epidermal nevus, and incontinentia pigmenti.^6,7 Lichen planus-like chronic GVHD occurring in a linear distribution has been described.^6-14 Distinction between dermatomal and blaschkoid processes is diagnostically important. In the case of GVHD, dermatomal distribution may suggest an association between GVHD and prior herpes simplex virus or varicella-zoster virus infection.^6,8 Herpesvirus may alter surface antigens of keratinocytes, rendering them targets of donor lymphocytes, and antibodies to viral particles may cross-react with host keratinocyte HLA antigens. It also is possible that dermatomal GVHD may simply be a type of isomorphic response (Köbner phenomenon).⁸

When cutaneous GVHD follows Blaschko lines, other mechanisms appear to be at play.^9-14 It is plausible that these patients have an underlying genetic mosaicism, perhaps the result of a postzygotic mutation, that results in a daughter cell population that expresses surface antigens different from those of the primary cell population found elsewhere in the skin. Donor lymphocytes may selectively react to this mosaic population, leading to the clinical picture of chronic GVHD oriented along Blaschko lines.^10,11,13,14 

In conclusion, lichenoid linear GVHD following Blaschko lines is an uncommon presentation of chronic GVHD that highlights the heterogeneity of this disease and should be considered in the appropriate clinical setting.

The Diagnosis: Blaschkoid Graft-vs-host Disease

The patient had a history of myelodysplastic syndrome and underwent a bone marrow transplant 1 year prior to presentation. She had acute graft-vs-host disease (GVHD) 6 weeks following the transplant, which resolved with high-dose prednisone followed by UVB phototherapy. Skin biopsy demonstrated lichenoid dermatitis with vacuolar degeneration, dyskeratosis, and prominent pigment incontinence (Figure). Based on these findings and her clinical presentation, a diagnosis of blaschkoid GVHD was made.

Although acute GVHD is the result of immunocompetent donor T cells recognizing host tissues as foreign and initiating an immune response, the pathophysiology of chronic GVHD is not well understood.^1,2 Theories for disease pathogenesis in chronic GVHD suggest an underlying autoimmune and/or alloreactive process.^2-5 The skin often is the first organ affected in acute GVHD, and patients generally present with a pruritic morbilliform eruption that begins on the trunk and spreads to the rest of the body.^1,2 Cutaneous manifestations of chronic GVHD may be protean. Lesions can resemble systemic sclerosis or morphea, lichen planus, psoriasis, ichthyosis, and many other conditions.²

The differential diagnosis of linear dermatoses includes herpes zoster, contact dermatitis, lichen striatus (blaschkitis), nevus unius lateris, inflammatory linear verrucous epidermal nevus, and incontinentia pigmenti.^6,7 Lichen planus-like chronic GVHD occurring in a linear distribution has been described.^6-14 Distinction between dermatomal and blaschkoid processes is diagnostically important. In the case of GVHD, dermatomal distribution may suggest an association between GVHD and prior herpes simplex virus or varicella-zoster virus infection.^6,8 Herpesvirus may alter surface antigens of keratinocytes, rendering them targets of donor lymphocytes, and antibodies to viral particles may cross-react with host keratinocyte HLA antigens. It also is possible that dermatomal GVHD may simply be a type of isomorphic response (Köbner phenomenon).⁸

When cutaneous GVHD follows Blaschko lines, other mechanisms appear to be at play.^9-14 It is plausible that these patients have an underlying genetic mosaicism, perhaps the result of a postzygotic mutation, that results in a daughter cell population that expresses surface antigens different from those of the primary cell population found elsewhere in the skin. Donor lymphocytes may selectively react to this mosaic population, leading to the clinical picture of chronic GVHD oriented along Blaschko lines.^10,11,13,14 

In conclusion, lichenoid linear GVHD following Blaschko lines is an uncommon presentation of chronic GVHD that highlights the heterogeneity of this disease and should be considered in the appropriate clinical setting.

The Diagnosis: Blaschkoid Graft-vs-host Disease

The patient had a history of myelodysplastic syndrome and underwent a bone marrow transplant 1 year prior to presentation. She had acute graft-vs-host disease (GVHD) 6 weeks following the transplant, which resolved with high-dose prednisone followed by UVB phototherapy. Skin biopsy demonstrated lichenoid dermatitis with vacuolar degeneration, dyskeratosis, and prominent pigment incontinence (Figure). Based on these findings and her clinical presentation, a diagnosis of blaschkoid GVHD was made.

Although acute GVHD is the result of immunocompetent donor T cells recognizing host tissues as foreign and initiating an immune response, the pathophysiology of chronic GVHD is not well understood.^1,2 Theories for disease pathogenesis in chronic GVHD suggest an underlying autoimmune and/or alloreactive process.^2-5 The skin often is the first organ affected in acute GVHD, and patients generally present with a pruritic morbilliform eruption that begins on the trunk and spreads to the rest of the body.^1,2 Cutaneous manifestations of chronic GVHD may be protean. Lesions can resemble systemic sclerosis or morphea, lichen planus, psoriasis, ichthyosis, and many other conditions.²

The differential diagnosis of linear dermatoses includes herpes zoster, contact dermatitis, lichen striatus (blaschkitis), nevus unius lateris, inflammatory linear verrucous epidermal nevus, and incontinentia pigmenti.^6,7 Lichen planus-like chronic GVHD occurring in a linear distribution has been described.^6-14 Distinction between dermatomal and blaschkoid processes is diagnostically important. In the case of GVHD, dermatomal distribution may suggest an association between GVHD and prior herpes simplex virus or varicella-zoster virus infection.^6,8 Herpesvirus may alter surface antigens of keratinocytes, rendering them targets of donor lymphocytes, and antibodies to viral particles may cross-react with host keratinocyte HLA antigens. It also is possible that dermatomal GVHD may simply be a type of isomorphic response (Köbner phenomenon).⁸

When cutaneous GVHD follows Blaschko lines, other mechanisms appear to be at play.^9-14 It is plausible that these patients have an underlying genetic mosaicism, perhaps the result of a postzygotic mutation, that results in a daughter cell population that expresses surface antigens different from those of the primary cell population found elsewhere in the skin. Donor lymphocytes may selectively react to this mosaic population, leading to the clinical picture of chronic GVHD oriented along Blaschko lines.^10,11,13,14 

In conclusion, lichenoid linear GVHD following Blaschko lines is an uncommon presentation of chronic GVHD that highlights the heterogeneity of this disease and should be considered in the appropriate clinical setting.

Papular Mucinosis/Scleromyxedema

Papular mucinosis/scleromyxedema, also known as generalized lichen myxedematosus, is a rare dermal mucinosis characterized by a papular eruption that can have an associated IgG λ paraproteinemia. The clinical presentation is gradual with the development of firm, flesh-colored, 2- to 3-mm papules often involving the hands, face, and neck that can progress to plaques that cover the entire body. Skin stiffening also can be seen.¹ Extracutaneous symptoms are common and include dysphagia, arthralgia, myopathy, and cardiac dysfunction.² Occasionally, central nervous system involvement can lead to the often fatal dermato-neuro syndrome.^3,4

Histologically, papular mucinosis/scleromyxedema demonstrates increased, irregularly arranged fibroblasts in the reticular dermis with increased dermal mucin deposition (quiz image and Figure 1). The epidermis is normal or slightly thinned due to pressure from dermal changes. There may be a mild superficial perivascular lymphocytic infiltrate and atrophy of hair follicles.5 In this case, the clinical and histologic findings best supported a diagnosis of papular mucinosis/scleromyxedema.

Infundibulofolliculitis is a pruritic follicular papular eruption typically involving the neck, trunk, and proximal upper arms and shoulders. It is most common in black men who reside in hot and humid climates. Although infundibulofolliculitis would be included in the clinical differential diagnosis for the current patient, the histopathologic findings were quite distinct for the correct diagnosis of papular mucinosis/scleromyxedema. Infundibulofolliculitis shows widening of the upper part of the hair follicle (infundibulum) and infundibular inflammatory infiltrate with follicular spongiosis (Figure 2). Neither mucin deposition nor fibroblast proliferation is appreciated in infundibulofolliculitis.^6,7 

Granuloma annulare (GA) often can be distinguished clinically from papular mucinosis/scleromyxedema due to the annular appearance of papules and plaques in GA and the lack of stiffness of underlying skin. Interstitial granuloma annulare is a histologic variant of GA that can be included in the histologic differential diagnosis of papular mucinosis/scleromyxedema. Histologically, there is an interstitial infiltrate of cytologically bland histiocytes dissecting between collagen bundles in interstitial GA (Figure 3). Necrobiosis and collections of mucin often are inconspicuous. Occasionally, the presence of eosinophils can be a helpful clue.⁸ A fibroblast proliferation is not a feature of GA.

Reticular erythematous mucinosis also is a type of cutaneous mucinosis but with a classic clinical appearance of a reticulated erythematous plaque on the chest or back, making it clinically distinct from papular mucinosis/scleromyxedema and the presentation described in the current patient. Reticular erythematous mucinosis can be histologically distinguished from papular mucinosis/scleromyxedema by the presence of a superficial and deep perivascular lymphocytic infiltrate with increased dermal mucin deposition (Figure 4). It often shows a positive IgM deposition on the basement membrane on direct immunofluorescence.⁹

Similar to papular mucinosis/scleromyxedema, scleredema shows thickening of the skin with decreased movement of involved areas. Scleredema often involves the upper back, shoulders, and neck where affected areas often have a peau d'orange appearance. Scleredema is classified into 3 clinical forms based on clinical associations. Type 1 often is preceded by an infection, classically Streptococcus pyogenes. Type 2 is associated with a hematologic dyscrasia such as multiple myeloma, or it can have an associated paraproteinemia that is typically of the IgA κ type, which is distinct from papular mucinosis/scleromyxedema where IgG λ paraproteinemia typically is seen. Type 3 is associated with diabetes mellitus. Histologically, scleredema also is distinct from papular mucinosis/scleromyxedema. Although increased mucin is seen in the dermis, the mucin is classically more prominent in the deep reticular dermis as compared with papular mucinosis/scleromyxedema (Figure 5). Additionally, collagen bundles are thickened with clear separation between them. Hyperplasia of fibroblasts in the dermis that is a characteristic feature of papular mucinosis/scleromyxedema is not observed in scleredema.¹⁰

Papular Mucinosis/Scleromyxedema

Papular mucinosis/scleromyxedema, also known as generalized lichen myxedematosus, is a rare dermal mucinosis characterized by a papular eruption that can have an associated IgG λ paraproteinemia. The clinical presentation is gradual with the development of firm, flesh-colored, 2- to 3-mm papules often involving the hands, face, and neck that can progress to plaques that cover the entire body. Skin stiffening also can be seen.¹ Extracutaneous symptoms are common and include dysphagia, arthralgia, myopathy, and cardiac dysfunction.² Occasionally, central nervous system involvement can lead to the often fatal dermato-neuro syndrome.^3,4

Histologically, papular mucinosis/scleromyxedema demonstrates increased, irregularly arranged fibroblasts in the reticular dermis with increased dermal mucin deposition (quiz image and Figure 1). The epidermis is normal or slightly thinned due to pressure from dermal changes. There may be a mild superficial perivascular lymphocytic infiltrate and atrophy of hair follicles.5 In this case, the clinical and histologic findings best supported a diagnosis of papular mucinosis/scleromyxedema.

Infundibulofolliculitis is a pruritic follicular papular eruption typically involving the neck, trunk, and proximal upper arms and shoulders. It is most common in black men who reside in hot and humid climates. Although infundibulofolliculitis would be included in the clinical differential diagnosis for the current patient, the histopathologic findings were quite distinct for the correct diagnosis of papular mucinosis/scleromyxedema. Infundibulofolliculitis shows widening of the upper part of the hair follicle (infundibulum) and infundibular inflammatory infiltrate with follicular spongiosis (Figure 2). Neither mucin deposition nor fibroblast proliferation is appreciated in infundibulofolliculitis.^6,7 

Granuloma annulare (GA) often can be distinguished clinically from papular mucinosis/scleromyxedema due to the annular appearance of papules and plaques in GA and the lack of stiffness of underlying skin. Interstitial granuloma annulare is a histologic variant of GA that can be included in the histologic differential diagnosis of papular mucinosis/scleromyxedema. Histologically, there is an interstitial infiltrate of cytologically bland histiocytes dissecting between collagen bundles in interstitial GA (Figure 3). Necrobiosis and collections of mucin often are inconspicuous. Occasionally, the presence of eosinophils can be a helpful clue.⁸ A fibroblast proliferation is not a feature of GA.

Reticular erythematous mucinosis also is a type of cutaneous mucinosis but with a classic clinical appearance of a reticulated erythematous plaque on the chest or back, making it clinically distinct from papular mucinosis/scleromyxedema and the presentation described in the current patient. Reticular erythematous mucinosis can be histologically distinguished from papular mucinosis/scleromyxedema by the presence of a superficial and deep perivascular lymphocytic infiltrate with increased dermal mucin deposition (Figure 4). It often shows a positive IgM deposition on the basement membrane on direct immunofluorescence.⁹

Similar to papular mucinosis/scleromyxedema, scleredema shows thickening of the skin with decreased movement of involved areas. Scleredema often involves the upper back, shoulders, and neck where affected areas often have a peau d'orange appearance. Scleredema is classified into 3 clinical forms based on clinical associations. Type 1 often is preceded by an infection, classically Streptococcus pyogenes. Type 2 is associated with a hematologic dyscrasia such as multiple myeloma, or it can have an associated paraproteinemia that is typically of the IgA κ type, which is distinct from papular mucinosis/scleromyxedema where IgG λ paraproteinemia typically is seen. Type 3 is associated with diabetes mellitus. Histologically, scleredema also is distinct from papular mucinosis/scleromyxedema. Although increased mucin is seen in the dermis, the mucin is classically more prominent in the deep reticular dermis as compared with papular mucinosis/scleromyxedema (Figure 5). Additionally, collagen bundles are thickened with clear separation between them. Hyperplasia of fibroblasts in the dermis that is a characteristic feature of papular mucinosis/scleromyxedema is not observed in scleredema.¹⁰

Papular Mucinosis/Scleromyxedema

Papular mucinosis/scleromyxedema, also known as generalized lichen myxedematosus, is a rare dermal mucinosis characterized by a papular eruption that can have an associated IgG λ paraproteinemia. The clinical presentation is gradual with the development of firm, flesh-colored, 2- to 3-mm papules often involving the hands, face, and neck that can progress to plaques that cover the entire body. Skin stiffening also can be seen.¹ Extracutaneous symptoms are common and include dysphagia, arthralgia, myopathy, and cardiac dysfunction.² Occasionally, central nervous system involvement can lead to the often fatal dermato-neuro syndrome.^3,4

Histologically, papular mucinosis/scleromyxedema demonstrates increased, irregularly arranged fibroblasts in the reticular dermis with increased dermal mucin deposition (quiz image and Figure 1). The epidermis is normal or slightly thinned due to pressure from dermal changes. There may be a mild superficial perivascular lymphocytic infiltrate and atrophy of hair follicles.5 In this case, the clinical and histologic findings best supported a diagnosis of papular mucinosis/scleromyxedema.

Infundibulofolliculitis is a pruritic follicular papular eruption typically involving the neck, trunk, and proximal upper arms and shoulders. It is most common in black men who reside in hot and humid climates. Although infundibulofolliculitis would be included in the clinical differential diagnosis for the current patient, the histopathologic findings were quite distinct for the correct diagnosis of papular mucinosis/scleromyxedema. Infundibulofolliculitis shows widening of the upper part of the hair follicle (infundibulum) and infundibular inflammatory infiltrate with follicular spongiosis (Figure 2). Neither mucin deposition nor fibroblast proliferation is appreciated in infundibulofolliculitis.^6,7 

Granuloma annulare (GA) often can be distinguished clinically from papular mucinosis/scleromyxedema due to the annular appearance of papules and plaques in GA and the lack of stiffness of underlying skin. Interstitial granuloma annulare is a histologic variant of GA that can be included in the histologic differential diagnosis of papular mucinosis/scleromyxedema. Histologically, there is an interstitial infiltrate of cytologically bland histiocytes dissecting between collagen bundles in interstitial GA (Figure 3). Necrobiosis and collections of mucin often are inconspicuous. Occasionally, the presence of eosinophils can be a helpful clue.⁸ A fibroblast proliferation is not a feature of GA.

Reticular erythematous mucinosis also is a type of cutaneous mucinosis but with a classic clinical appearance of a reticulated erythematous plaque on the chest or back, making it clinically distinct from papular mucinosis/scleromyxedema and the presentation described in the current patient. Reticular erythematous mucinosis can be histologically distinguished from papular mucinosis/scleromyxedema by the presence of a superficial and deep perivascular lymphocytic infiltrate with increased dermal mucin deposition (Figure 4). It often shows a positive IgM deposition on the basement membrane on direct immunofluorescence.⁹

Similar to papular mucinosis/scleromyxedema, scleredema shows thickening of the skin with decreased movement of involved areas. Scleredema often involves the upper back, shoulders, and neck where affected areas often have a peau d'orange appearance. Scleredema is classified into 3 clinical forms based on clinical associations. Type 1 often is preceded by an infection, classically Streptococcus pyogenes. Type 2 is associated with a hematologic dyscrasia such as multiple myeloma, or it can have an associated paraproteinemia that is typically of the IgA κ type, which is distinct from papular mucinosis/scleromyxedema where IgG λ paraproteinemia typically is seen. Type 3 is associated with diabetes mellitus. Histologically, scleredema also is distinct from papular mucinosis/scleromyxedema. Although increased mucin is seen in the dermis, the mucin is classically more prominent in the deep reticular dermis as compared with papular mucinosis/scleromyxedema (Figure 5). Additionally, collagen bundles are thickened with clear separation between them. Hyperplasia of fibroblasts in the dermis that is a characteristic feature of papular mucinosis/scleromyxedema is not observed in scleredema.¹⁰

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that most commonly affects the lungs, eyes, and skin. Cutaneous involvement is reported in 25% to 35% of patients with sarcoidosis and may occur in a variety of forms including macules, papules, plaques, and lupus pernio.^1,2 Dermatologists commonly are confronted with the diagnosis and management of sarcoidosis because of its high incidence of cutaneous involvement. Due to the protean nature of the disease, skin biopsy plays a key role in confirming the diagnosis. Histological evidence of noncaseating granulomas in combination with an appropriate clinical and radiographic picture is necessary for the diagnosis of sarcoidosis.^1,2 Brincker and Wilbek³ first described the link between pulmonary sarcoidosis and an increased incidence of malignancy in 1974. Since then, a number of studies have suggested that sarcoidosis may be associated with an increased risk for hematologic malignancy as well as an increased risk for cancers of the lungs, stomach, colon, liver, and skin.^4,5 To date, few studies exist that examine the relationship between cutaneous sarcoidosis and malignancy.⁶

We describe 3 patients with sarcoidosis who developed squamous cell carcinoma (SCC) of the skin, including 2 black patients, which highlights the potential for SCC development.

Case Reports

Patient 1

A black woman in her 60s with a history of sarcoidosis affecting the lungs and skin that was well controlled with biweekly adalimumab 40 mg subcutaneous injections presented with a new dark painful lesion on the right third finger. She reported the lesion had been present for 1 to 2 years prior to the current presentation and was increasing in size. She had no history of prior skin cancers.

Physical examination revealed a waxy, brown-pigmented papule with overlying scale on the ulnar aspect of the right third digit near the web space (Figure 1A). A shave biopsy revealed atypical keratinocytes involving all layers of the epidermis along with associated parakeratotic scale consistent with a diagnosis of SCC in situ (Figure 1B). Human papillomavirus staining was negative. Due to the location of the lesion, the patient underwent Mohs micrographic surgery and the lesion was completely excised.

Patient 2

A black woman in her 60s with a history of cutaneous sarcoidosis that was maintained on minocycline 100 mg twice daily, chloroquine 250 mg daily, tacrolimus ointment 0.1%, tretinoin cream 0.025%, and intermittent intralesional triamcinolone acetonide injections to the nose, as well as quiescent pulmonary sarcoidosis, developed a new, growing, asymptomatic, hyperpigmented lesion on the left side of the submandibular neck over a period of a few months. A biopsy was performed and the lesion was found to be an SCC, which subsequently was completely excised.

Patient 3

A white man in his 60s with a history of prior quiescent pulmonary sarcoidosis, remote melanoma, and multiple nonmelanoma skin cancers developed scaly papules on the scalp for months, one that was interpreted by an outside pathologist as an invasive SCC (Figure 2A). He was referred to our institution for Mohs micrographic surgery. On presentation when his scalp was shaved for surgery, he was noted to have several violaceous, annular, thin plaques on the scalp (Figure 2B). A biopsy of an annular plaque demonstrated several areas of granulomatous dermatitis consistent with a diagnosis of cutaneous sarcoidosis (Figure 2C). The patient had clinical lymphadenopathy of the neck and supraclavicular region. Given the patient’s history, the differential diagnosis for these lesions included metastatic SCC, lymphoma, and sarcoidosis. The patient underwent a positron emission tomography scan, which demonstrated fluorodeoxyglucose-positive regions in both lungs and the right side of the neck. After evaluation by the pulmonary and otorhinolaryngology departments, including a lymph node biopsy, the positron emission tomography–enhancing lesions were ultimately determined to be consistent with sarcoidosis.

The patient underwent Mohs micrographic surgery for treatment of the scalp SCC and was started on triamcinolone cream 0.1% for the body, clobetasol propionate foam 0.05% for the scalp, and hydroxychloroquine sulfate 400 mg daily for the cutaneous sarcoidosis. His annular scalp lesions resolved, but over the following 12 months the patient had numerous clinically suspicious skin lesions that were biopsied and were consistent with multiple basal cell carcinomas, actinic keratoses, and SCC in situ. They were treated with surgery, cryosurgical destruction with liquid nitrogen, and 5-fluorouracil cream.

Comment

The potential increased risk for malignancy in patients with sarcoidosis has been well documented.^3-6 Brincker and Wilbek³ first reported this association after studying 2544 patients with pulmonary sarcoidosis from 1962 to 1971. In particular, they noted a difference between the expected and observed number of cases of malignancy, particularly lung cancer and lymphoma, in the sarcoidosis population.³ In a study of 10,037 hospitalized sarcoidosis patients from 1964 to 2004, Ji et al⁵ noted a 40% overall increase in the incidence of cancer and found that the risk for malignancy was highest in the year following hospitalization. Interestingly, they found that the risk for developing cutaneous SCC was elevated in sarcoidosis patients even after the first year following hospitalization.⁵ In a retrospective cohort study examining more than 9000 patients, Askling et al⁴ also confirmed the increased incidence of malignancy in sarcoidosis patients. Specifically, the authors found a higher than expected occurrence of skin cancer, both melanoma (standardized incidence ratio, 1.6; 95% confidence interval, 1.1-2.3) and nonmelanoma skin cancer (standardized incidence ratio, 2.8; 95% confidence interval, 2.0-3.8) in patients with sarcoidosis.⁴ Reich et al⁷ cross-matched 30,000 cases from the Kaiser Permanente Northwest Region Tumor Registry against a sarcoidosis registry of 243 cases to evaluate for evidence of linkage between sarcoidosis and malignancy. They concluded that there may be an etiologic relationship between sarcoidosis and malignancy in at least one-quarter of cases in which both are present and hypothesized that granulomas may be the result of a cell-mediated reaction to tumor antigens.⁷

Few published studies specifically address the incidence of malignancy in patients with primarily cutaneous sarcoidosis. Cutaneous sarcoidosis includes nonspecific lesions, such as erythema nodosum, as well as specific lesions, such as papules, plaques, nodules, and lupus pernio.⁸ Alexandrescu et al⁶ evaluated 110 patients with a diagnosis of both sarcoidosis (cutaneous and noncutaneous) and malignancy. Through their analysis, they found that cutaneous sarcoidosis is seen more commonly in patients presenting with sarcoidosis and malignancy (56.4%) than in the total sarcoidosis population (20%–25%). From these findings, the authors concluded that cutaneous sarcoidosis appears to be a subtype of sarcoidosis associated with cancer.⁶

We report 3 cases that specifically illustrate a link between cutaneous sarcoidosis and an increased risk for cutaneous SCC. Because sarcoidosis commonly affects the skin, patients often present to dermatologists for care. Once the initial diagnosis of cutaneous sarcoidosis is made via biopsy, it is natural to be tempted to attribute any new skin lesions to worsening or active disease; however, as cutaneous sarcoidosis may take on a variety of nonspecific forms, it is important to biopsy any unusual lesions. In our case series, patient 3 presented at several different points with scaly scalp lesions. Upon biopsy, several of these lesions were found to be SCCs, while others demonstrated regions of granulomatous inflammation consistent with a diagnosis of cutaneous sarcoidosis. On further review of pathology during the preparation of this manuscript after the initial diagnoses were made, it was further noted that it is challenging to distinguish granulomatous inflammation with reactive pseudoepitheliomatous hyperplasia from SCC. The fact that these lesions were clinically indistinguishable illustrates the critical importance of appropriate-depth biopsy in this situation, and the histopathologic challenges highlighted herein are important for pathologists to remember.

Patients 1 and 2 were both black women, and the fact that these patients both presented with cutaneous SCCs—one of whom was immunosuppressed due to treatment with adalimumab, the other without systemic immunosuppression—exemplifies the need for comprehensive skin examinations in sarcoidosis patients as well as for biopsies of new or unusual lesions.

The mechanism for the development of malignancy in patients with sarcoidosis is unknown and likely is multifactorial. Multiple theories have been proposed.^1,2,5,6,8 Sarcoidosis is marked by the development of granulomas secondary to the interaction between CD4⁺ T cells and antigen-presenting cells, which is mediated by various cytokines and chemokines, including IL-2 and IFN-γ. Patients with sarcoidosis have been found to have oligoclonal T-cell lineages with a limited receptor repertoire, suggestive of selective immune system activation, as well as a deficiency of certain types of regulatory cells, namely natural killer cells.^1,2 This immune dysregulation has been postulated to play an etiologic role in the development of malignancy in sarcoidosis patients.^1,2,5 Furthermore, the chronic inflammation found in the organs commonly affected by both sarcoidosis and malignancy is another possible mechanism.^6,8 Finally, immunosuppression and mutagenesis secondary to the treatment modalities used in sarcoidosis may be another contributing factor.⁶

Conclusion

An association between sarcoidosis and malignancy has been suggested for several decades. We specifically report 3 cases of patients with cutaneous sarcoidosis who presented with concurrent cutaneous SCCs. Given the varied and often nonspecific nature of cutaneous sarcoidosis, these cases highlight the importance of biopsy when sarcoidosis patients present with new and unusual skin lesions. Additionally, they illustrate the importance of thorough skin examinations in sarcoidosis patients as well as some of the challenges these patients pose for dermatologists.

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that most commonly affects the lungs, eyes, and skin. Cutaneous involvement is reported in 25% to 35% of patients with sarcoidosis and may occur in a variety of forms including macules, papules, plaques, and lupus pernio.^1,2 Dermatologists commonly are confronted with the diagnosis and management of sarcoidosis because of its high incidence of cutaneous involvement. Due to the protean nature of the disease, skin biopsy plays a key role in confirming the diagnosis. Histological evidence of noncaseating granulomas in combination with an appropriate clinical and radiographic picture is necessary for the diagnosis of sarcoidosis.^1,2 Brincker and Wilbek³ first described the link between pulmonary sarcoidosis and an increased incidence of malignancy in 1974. Since then, a number of studies have suggested that sarcoidosis may be associated with an increased risk for hematologic malignancy as well as an increased risk for cancers of the lungs, stomach, colon, liver, and skin.^4,5 To date, few studies exist that examine the relationship between cutaneous sarcoidosis and malignancy.⁶

We describe 3 patients with sarcoidosis who developed squamous cell carcinoma (SCC) of the skin, including 2 black patients, which highlights the potential for SCC development.

Case Reports

Patient 1

A black woman in her 60s with a history of sarcoidosis affecting the lungs and skin that was well controlled with biweekly adalimumab 40 mg subcutaneous injections presented with a new dark painful lesion on the right third finger. She reported the lesion had been present for 1 to 2 years prior to the current presentation and was increasing in size. She had no history of prior skin cancers.

Physical examination revealed a waxy, brown-pigmented papule with overlying scale on the ulnar aspect of the right third digit near the web space (Figure 1A). A shave biopsy revealed atypical keratinocytes involving all layers of the epidermis along with associated parakeratotic scale consistent with a diagnosis of SCC in situ (Figure 1B). Human papillomavirus staining was negative. Due to the location of the lesion, the patient underwent Mohs micrographic surgery and the lesion was completely excised.

Patient 2

A black woman in her 60s with a history of cutaneous sarcoidosis that was maintained on minocycline 100 mg twice daily, chloroquine 250 mg daily, tacrolimus ointment 0.1%, tretinoin cream 0.025%, and intermittent intralesional triamcinolone acetonide injections to the nose, as well as quiescent pulmonary sarcoidosis, developed a new, growing, asymptomatic, hyperpigmented lesion on the left side of the submandibular neck over a period of a few months. A biopsy was performed and the lesion was found to be an SCC, which subsequently was completely excised.

Patient 3

A white man in his 60s with a history of prior quiescent pulmonary sarcoidosis, remote melanoma, and multiple nonmelanoma skin cancers developed scaly papules on the scalp for months, one that was interpreted by an outside pathologist as an invasive SCC (Figure 2A). He was referred to our institution for Mohs micrographic surgery. On presentation when his scalp was shaved for surgery, he was noted to have several violaceous, annular, thin plaques on the scalp (Figure 2B). A biopsy of an annular plaque demonstrated several areas of granulomatous dermatitis consistent with a diagnosis of cutaneous sarcoidosis (Figure 2C). The patient had clinical lymphadenopathy of the neck and supraclavicular region. Given the patient’s history, the differential diagnosis for these lesions included metastatic SCC, lymphoma, and sarcoidosis. The patient underwent a positron emission tomography scan, which demonstrated fluorodeoxyglucose-positive regions in both lungs and the right side of the neck. After evaluation by the pulmonary and otorhinolaryngology departments, including a lymph node biopsy, the positron emission tomography–enhancing lesions were ultimately determined to be consistent with sarcoidosis.

The patient underwent Mohs micrographic surgery for treatment of the scalp SCC and was started on triamcinolone cream 0.1% for the body, clobetasol propionate foam 0.05% for the scalp, and hydroxychloroquine sulfate 400 mg daily for the cutaneous sarcoidosis. His annular scalp lesions resolved, but over the following 12 months the patient had numerous clinically suspicious skin lesions that were biopsied and were consistent with multiple basal cell carcinomas, actinic keratoses, and SCC in situ. They were treated with surgery, cryosurgical destruction with liquid nitrogen, and 5-fluorouracil cream.

Comment

The potential increased risk for malignancy in patients with sarcoidosis has been well documented.^3-6 Brincker and Wilbek³ first reported this association after studying 2544 patients with pulmonary sarcoidosis from 1962 to 1971. In particular, they noted a difference between the expected and observed number of cases of malignancy, particularly lung cancer and lymphoma, in the sarcoidosis population.³ In a study of 10,037 hospitalized sarcoidosis patients from 1964 to 2004, Ji et al⁵ noted a 40% overall increase in the incidence of cancer and found that the risk for malignancy was highest in the year following hospitalization. Interestingly, they found that the risk for developing cutaneous SCC was elevated in sarcoidosis patients even after the first year following hospitalization.⁵ In a retrospective cohort study examining more than 9000 patients, Askling et al⁴ also confirmed the increased incidence of malignancy in sarcoidosis patients. Specifically, the authors found a higher than expected occurrence of skin cancer, both melanoma (standardized incidence ratio, 1.6; 95% confidence interval, 1.1-2.3) and nonmelanoma skin cancer (standardized incidence ratio, 2.8; 95% confidence interval, 2.0-3.8) in patients with sarcoidosis.⁴ Reich et al⁷ cross-matched 30,000 cases from the Kaiser Permanente Northwest Region Tumor Registry against a sarcoidosis registry of 243 cases to evaluate for evidence of linkage between sarcoidosis and malignancy. They concluded that there may be an etiologic relationship between sarcoidosis and malignancy in at least one-quarter of cases in which both are present and hypothesized that granulomas may be the result of a cell-mediated reaction to tumor antigens.⁷

Few published studies specifically address the incidence of malignancy in patients with primarily cutaneous sarcoidosis. Cutaneous sarcoidosis includes nonspecific lesions, such as erythema nodosum, as well as specific lesions, such as papules, plaques, nodules, and lupus pernio.⁸ Alexandrescu et al⁶ evaluated 110 patients with a diagnosis of both sarcoidosis (cutaneous and noncutaneous) and malignancy. Through their analysis, they found that cutaneous sarcoidosis is seen more commonly in patients presenting with sarcoidosis and malignancy (56.4%) than in the total sarcoidosis population (20%–25%). From these findings, the authors concluded that cutaneous sarcoidosis appears to be a subtype of sarcoidosis associated with cancer.⁶

We report 3 cases that specifically illustrate a link between cutaneous sarcoidosis and an increased risk for cutaneous SCC. Because sarcoidosis commonly affects the skin, patients often present to dermatologists for care. Once the initial diagnosis of cutaneous sarcoidosis is made via biopsy, it is natural to be tempted to attribute any new skin lesions to worsening or active disease; however, as cutaneous sarcoidosis may take on a variety of nonspecific forms, it is important to biopsy any unusual lesions. In our case series, patient 3 presented at several different points with scaly scalp lesions. Upon biopsy, several of these lesions were found to be SCCs, while others demonstrated regions of granulomatous inflammation consistent with a diagnosis of cutaneous sarcoidosis. On further review of pathology during the preparation of this manuscript after the initial diagnoses were made, it was further noted that it is challenging to distinguish granulomatous inflammation with reactive pseudoepitheliomatous hyperplasia from SCC. The fact that these lesions were clinically indistinguishable illustrates the critical importance of appropriate-depth biopsy in this situation, and the histopathologic challenges highlighted herein are important for pathologists to remember.

Patients 1 and 2 were both black women, and the fact that these patients both presented with cutaneous SCCs—one of whom was immunosuppressed due to treatment with adalimumab, the other without systemic immunosuppression—exemplifies the need for comprehensive skin examinations in sarcoidosis patients as well as for biopsies of new or unusual lesions.

The mechanism for the development of malignancy in patients with sarcoidosis is unknown and likely is multifactorial. Multiple theories have been proposed.^1,2,5,6,8 Sarcoidosis is marked by the development of granulomas secondary to the interaction between CD4⁺ T cells and antigen-presenting cells, which is mediated by various cytokines and chemokines, including IL-2 and IFN-γ. Patients with sarcoidosis have been found to have oligoclonal T-cell lineages with a limited receptor repertoire, suggestive of selective immune system activation, as well as a deficiency of certain types of regulatory cells, namely natural killer cells.^1,2 This immune dysregulation has been postulated to play an etiologic role in the development of malignancy in sarcoidosis patients.^1,2,5 Furthermore, the chronic inflammation found in the organs commonly affected by both sarcoidosis and malignancy is another possible mechanism.^6,8 Finally, immunosuppression and mutagenesis secondary to the treatment modalities used in sarcoidosis may be another contributing factor.⁶

Conclusion

An association between sarcoidosis and malignancy has been suggested for several decades. We specifically report 3 cases of patients with cutaneous sarcoidosis who presented with concurrent cutaneous SCCs. Given the varied and often nonspecific nature of cutaneous sarcoidosis, these cases highlight the importance of biopsy when sarcoidosis patients present with new and unusual skin lesions. Additionally, they illustrate the importance of thorough skin examinations in sarcoidosis patients as well as some of the challenges these patients pose for dermatologists.

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that most commonly affects the lungs, eyes, and skin. Cutaneous involvement is reported in 25% to 35% of patients with sarcoidosis and may occur in a variety of forms including macules, papules, plaques, and lupus pernio.^1,2 Dermatologists commonly are confronted with the diagnosis and management of sarcoidosis because of its high incidence of cutaneous involvement. Due to the protean nature of the disease, skin biopsy plays a key role in confirming the diagnosis. Histological evidence of noncaseating granulomas in combination with an appropriate clinical and radiographic picture is necessary for the diagnosis of sarcoidosis.^1,2 Brincker and Wilbek³ first described the link between pulmonary sarcoidosis and an increased incidence of malignancy in 1974. Since then, a number of studies have suggested that sarcoidosis may be associated with an increased risk for hematologic malignancy as well as an increased risk for cancers of the lungs, stomach, colon, liver, and skin.^4,5 To date, few studies exist that examine the relationship between cutaneous sarcoidosis and malignancy.⁶

We describe 3 patients with sarcoidosis who developed squamous cell carcinoma (SCC) of the skin, including 2 black patients, which highlights the potential for SCC development.

Case Reports

Patient 1

A black woman in her 60s with a history of sarcoidosis affecting the lungs and skin that was well controlled with biweekly adalimumab 40 mg subcutaneous injections presented with a new dark painful lesion on the right third finger. She reported the lesion had been present for 1 to 2 years prior to the current presentation and was increasing in size. She had no history of prior skin cancers.

Physical examination revealed a waxy, brown-pigmented papule with overlying scale on the ulnar aspect of the right third digit near the web space (Figure 1A). A shave biopsy revealed atypical keratinocytes involving all layers of the epidermis along with associated parakeratotic scale consistent with a diagnosis of SCC in situ (Figure 1B). Human papillomavirus staining was negative. Due to the location of the lesion, the patient underwent Mohs micrographic surgery and the lesion was completely excised.

Patient 2

A black woman in her 60s with a history of cutaneous sarcoidosis that was maintained on minocycline 100 mg twice daily, chloroquine 250 mg daily, tacrolimus ointment 0.1%, tretinoin cream 0.025%, and intermittent intralesional triamcinolone acetonide injections to the nose, as well as quiescent pulmonary sarcoidosis, developed a new, growing, asymptomatic, hyperpigmented lesion on the left side of the submandibular neck over a period of a few months. A biopsy was performed and the lesion was found to be an SCC, which subsequently was completely excised.

Patient 3

A white man in his 60s with a history of prior quiescent pulmonary sarcoidosis, remote melanoma, and multiple nonmelanoma skin cancers developed scaly papules on the scalp for months, one that was interpreted by an outside pathologist as an invasive SCC (Figure 2A). He was referred to our institution for Mohs micrographic surgery. On presentation when his scalp was shaved for surgery, he was noted to have several violaceous, annular, thin plaques on the scalp (Figure 2B). A biopsy of an annular plaque demonstrated several areas of granulomatous dermatitis consistent with a diagnosis of cutaneous sarcoidosis (Figure 2C). The patient had clinical lymphadenopathy of the neck and supraclavicular region. Given the patient’s history, the differential diagnosis for these lesions included metastatic SCC, lymphoma, and sarcoidosis. The patient underwent a positron emission tomography scan, which demonstrated fluorodeoxyglucose-positive regions in both lungs and the right side of the neck. After evaluation by the pulmonary and otorhinolaryngology departments, including a lymph node biopsy, the positron emission tomography–enhancing lesions were ultimately determined to be consistent with sarcoidosis.

The patient underwent Mohs micrographic surgery for treatment of the scalp SCC and was started on triamcinolone cream 0.1% for the body, clobetasol propionate foam 0.05% for the scalp, and hydroxychloroquine sulfate 400 mg daily for the cutaneous sarcoidosis. His annular scalp lesions resolved, but over the following 12 months the patient had numerous clinically suspicious skin lesions that were biopsied and were consistent with multiple basal cell carcinomas, actinic keratoses, and SCC in situ. They were treated with surgery, cryosurgical destruction with liquid nitrogen, and 5-fluorouracil cream.

Comment

The potential increased risk for malignancy in patients with sarcoidosis has been well documented.^3-6 Brincker and Wilbek³ first reported this association after studying 2544 patients with pulmonary sarcoidosis from 1962 to 1971. In particular, they noted a difference between the expected and observed number of cases of malignancy, particularly lung cancer and lymphoma, in the sarcoidosis population.³ In a study of 10,037 hospitalized sarcoidosis patients from 1964 to 2004, Ji et al⁵ noted a 40% overall increase in the incidence of cancer and found that the risk for malignancy was highest in the year following hospitalization. Interestingly, they found that the risk for developing cutaneous SCC was elevated in sarcoidosis patients even after the first year following hospitalization.⁵ In a retrospective cohort study examining more than 9000 patients, Askling et al⁴ also confirmed the increased incidence of malignancy in sarcoidosis patients. Specifically, the authors found a higher than expected occurrence of skin cancer, both melanoma (standardized incidence ratio, 1.6; 95% confidence interval, 1.1-2.3) and nonmelanoma skin cancer (standardized incidence ratio, 2.8; 95% confidence interval, 2.0-3.8) in patients with sarcoidosis.⁴ Reich et al⁷ cross-matched 30,000 cases from the Kaiser Permanente Northwest Region Tumor Registry against a sarcoidosis registry of 243 cases to evaluate for evidence of linkage between sarcoidosis and malignancy. They concluded that there may be an etiologic relationship between sarcoidosis and malignancy in at least one-quarter of cases in which both are present and hypothesized that granulomas may be the result of a cell-mediated reaction to tumor antigens.⁷

Few published studies specifically address the incidence of malignancy in patients with primarily cutaneous sarcoidosis. Cutaneous sarcoidosis includes nonspecific lesions, such as erythema nodosum, as well as specific lesions, such as papules, plaques, nodules, and lupus pernio.⁸ Alexandrescu et al⁶ evaluated 110 patients with a diagnosis of both sarcoidosis (cutaneous and noncutaneous) and malignancy. Through their analysis, they found that cutaneous sarcoidosis is seen more commonly in patients presenting with sarcoidosis and malignancy (56.4%) than in the total sarcoidosis population (20%–25%). From these findings, the authors concluded that cutaneous sarcoidosis appears to be a subtype of sarcoidosis associated with cancer.⁶

We report 3 cases that specifically illustrate a link between cutaneous sarcoidosis and an increased risk for cutaneous SCC. Because sarcoidosis commonly affects the skin, patients often present to dermatologists for care. Once the initial diagnosis of cutaneous sarcoidosis is made via biopsy, it is natural to be tempted to attribute any new skin lesions to worsening or active disease; however, as cutaneous sarcoidosis may take on a variety of nonspecific forms, it is important to biopsy any unusual lesions. In our case series, patient 3 presented at several different points with scaly scalp lesions. Upon biopsy, several of these lesions were found to be SCCs, while others demonstrated regions of granulomatous inflammation consistent with a diagnosis of cutaneous sarcoidosis. On further review of pathology during the preparation of this manuscript after the initial diagnoses were made, it was further noted that it is challenging to distinguish granulomatous inflammation with reactive pseudoepitheliomatous hyperplasia from SCC. The fact that these lesions were clinically indistinguishable illustrates the critical importance of appropriate-depth biopsy in this situation, and the histopathologic challenges highlighted herein are important for pathologists to remember.

Patients 1 and 2 were both black women, and the fact that these patients both presented with cutaneous SCCs—one of whom was immunosuppressed due to treatment with adalimumab, the other without systemic immunosuppression—exemplifies the need for comprehensive skin examinations in sarcoidosis patients as well as for biopsies of new or unusual lesions.

The mechanism for the development of malignancy in patients with sarcoidosis is unknown and likely is multifactorial. Multiple theories have been proposed.^1,2,5,6,8 Sarcoidosis is marked by the development of granulomas secondary to the interaction between CD4⁺ T cells and antigen-presenting cells, which is mediated by various cytokines and chemokines, including IL-2 and IFN-γ. Patients with sarcoidosis have been found to have oligoclonal T-cell lineages with a limited receptor repertoire, suggestive of selective immune system activation, as well as a deficiency of certain types of regulatory cells, namely natural killer cells.^1,2 This immune dysregulation has been postulated to play an etiologic role in the development of malignancy in sarcoidosis patients.^1,2,5 Furthermore, the chronic inflammation found in the organs commonly affected by both sarcoidosis and malignancy is another possible mechanism.^6,8 Finally, immunosuppression and mutagenesis secondary to the treatment modalities used in sarcoidosis may be another contributing factor.⁶

Conclusion

An association between sarcoidosis and malignancy has been suggested for several decades. We specifically report 3 cases of patients with cutaneous sarcoidosis who presented with concurrent cutaneous SCCs. Given the varied and often nonspecific nature of cutaneous sarcoidosis, these cases highlight the importance of biopsy when sarcoidosis patients present with new and unusual skin lesions. Additionally, they illustrate the importance of thorough skin examinations in sarcoidosis patients as well as some of the challenges these patients pose for dermatologists.

WASHINGTON – A novel biologic treatment strategy involving subcutaneous low-dose interleukin-2 therapy for refractory systemic lupus erythematosus (SLE) showed promise in a single-center, combined phase I/IIa trial.

In 12 patients with active and refractory SLE – that is, patients with SLE disease activity index (SLEDAI) score of at least 6 who were on at least two different immunosuppressive therapies – low-dose IL-2 treatment led to an effective and cycle-dependent increase in the percentage of CD25hi cells among regulatory T cells (Treg). The increase was statistically significant (P less than .001), Jens Humrich, MD, and his colleagues reported in a late-breaking poster at the annual meeting of the American College of Rheumatology.

wildpixel/Thinkstock

sworcester@frontlinemedcom.com

WASHINGTON – A novel biologic treatment strategy involving subcutaneous low-dose interleukin-2 therapy for refractory systemic lupus erythematosus (SLE) showed promise in a single-center, combined phase I/IIa trial.

In 12 patients with active and refractory SLE – that is, patients with SLE disease activity index (SLEDAI) score of at least 6 who were on at least two different immunosuppressive therapies – low-dose IL-2 treatment led to an effective and cycle-dependent increase in the percentage of CD25hi cells among regulatory T cells (Treg). The increase was statistically significant (P less than .001), Jens Humrich, MD, and his colleagues reported in a late-breaking poster at the annual meeting of the American College of Rheumatology.

wildpixel/Thinkstock

sworcester@frontlinemedcom.com

WASHINGTON – A novel biologic treatment strategy involving subcutaneous low-dose interleukin-2 therapy for refractory systemic lupus erythematosus (SLE) showed promise in a single-center, combined phase I/IIa trial.

In 12 patients with active and refractory SLE – that is, patients with SLE disease activity index (SLEDAI) score of at least 6 who were on at least two different immunosuppressive therapies – low-dose IL-2 treatment led to an effective and cycle-dependent increase in the percentage of CD25hi cells among regulatory T cells (Treg). The increase was statistically significant (P less than .001), Jens Humrich, MD, and his colleagues reported in a late-breaking poster at the annual meeting of the American College of Rheumatology.

wildpixel/Thinkstock

sworcester@frontlinemedcom.com

Blastomycosis
Blastomycosis is caused by Blastomyces dermatitidis, which is endemic in the Midwestern and southeastern United States where it occurs environmentally in wood and soil. Unlike many fungal infections, blastomycosis most often develops in immunocompetent hosts. Infection is usually acquired via inhalation,¹ and cutaneous disease typically is secondary to pulmonary infection. Although not common, traumatic inoculation also can cause cutaneous blastomycosis. Skin lesions include crusted verrucous nodules and plaques with elevated borders.^1,2 Histologic features include pseudoepitheliomatous hyperplasia with intraepidermal neutrophilic microabscesses (Figure 1), and a neutrophilic and granulomatous dermal infiltrate. Organisms often are found within histiocytes (quiz image) or small abscesses. The yeasts usually are 8 to 15 µm in diameter with a thick cell wall and occasionally display broad-based budding.

Chromoblastomycosis is caused by dematiaceous (pigmented) fungi, including Fonsecaea, Phialophora, Cladophialophora, and Rhinocladiella species,³ which are present in soil and vegetable debris in tropical and subtropical regions. Infection typically occurs in the foot or lower leg from traumatic inoculation, such as a thorn or splinter injury.² Histologically, chromoblastomycosis is characterized by pseudoepitheliomatous hyperplasia; suppurative and granulomatous dermatitis; and sclerotic (Medlar) bodies, which are 5 to 12 µm in diameter, round, brown, sometimes septate cells resembling copper pennies (Figure 2).²

Coccidioidomycosis is caused by Coccidioides immitis, which is found in soil in the southwestern United States. Infection most often occurs via inhalation of airborne arthrospores.² Cutaneous lesions occasionally are observed following dissemination or rarely following primary inoculation injury. They may present as papules, nodules, pustules, plaques, and ulcers, with the face being the most commonly affected site.¹ Histologically, coccidioidomycosis is characterized by pseudoepitheliomatous hyperplasia, suppurative and granulomatous dermatitis, and large spherules (up to 100 µm in diameter) containing numerous small endospores (Figure 3).

Cryptococcosis is caused by Cryptococcus neoformans, a fungus found in soil, fruit, and pigeon droppings throughout the world.^2,3 The most common route of infection is via the respiratory tract. Systemic spread and central nervous system involvement may occur in immunocompromised hosts.² Skin involvement is uncommon and may present on the head and neck with umbilicated papules, pustules, nodules, plaques, or ulcers. Histologically, Cryptococcus is a spherical yeast, often 4 to 20 µm in diameter. Replication is by narrow-based budding. A characteristic feature is a mucoid capsule, which retracts during processing, leaving a clear space around the yeast (Figure 4). When present, the mucoid capsule can be highlighted on mucicarmine or Alcian blue staining. Histologic variants of cryptococcosis include granulomatous (high host immune response), gelatinous (low host immune response), and suppurative types.³  

Blastomycosis
Blastomycosis is caused by Blastomyces dermatitidis, which is endemic in the Midwestern and southeastern United States where it occurs environmentally in wood and soil. Unlike many fungal infections, blastomycosis most often develops in immunocompetent hosts. Infection is usually acquired via inhalation,¹ and cutaneous disease typically is secondary to pulmonary infection. Although not common, traumatic inoculation also can cause cutaneous blastomycosis. Skin lesions include crusted verrucous nodules and plaques with elevated borders.^1,2 Histologic features include pseudoepitheliomatous hyperplasia with intraepidermal neutrophilic microabscesses (Figure 1), and a neutrophilic and granulomatous dermal infiltrate. Organisms often are found within histiocytes (quiz image) or small abscesses. The yeasts usually are 8 to 15 µm in diameter with a thick cell wall and occasionally display broad-based budding.

Chromoblastomycosis is caused by dematiaceous (pigmented) fungi, including Fonsecaea, Phialophora, Cladophialophora, and Rhinocladiella species,³ which are present in soil and vegetable debris in tropical and subtropical regions. Infection typically occurs in the foot or lower leg from traumatic inoculation, such as a thorn or splinter injury.² Histologically, chromoblastomycosis is characterized by pseudoepitheliomatous hyperplasia; suppurative and granulomatous dermatitis; and sclerotic (Medlar) bodies, which are 5 to 12 µm in diameter, round, brown, sometimes septate cells resembling copper pennies (Figure 2).²

Coccidioidomycosis is caused by Coccidioides immitis, which is found in soil in the southwestern United States. Infection most often occurs via inhalation of airborne arthrospores.² Cutaneous lesions occasionally are observed following dissemination or rarely following primary inoculation injury. They may present as papules, nodules, pustules, plaques, and ulcers, with the face being the most commonly affected site.¹ Histologically, coccidioidomycosis is characterized by pseudoepitheliomatous hyperplasia, suppurative and granulomatous dermatitis, and large spherules (up to 100 µm in diameter) containing numerous small endospores (Figure 3).

Cryptococcosis is caused by Cryptococcus neoformans, a fungus found in soil, fruit, and pigeon droppings throughout the world.^2,3 The most common route of infection is via the respiratory tract. Systemic spread and central nervous system involvement may occur in immunocompromised hosts.² Skin involvement is uncommon and may present on the head and neck with umbilicated papules, pustules, nodules, plaques, or ulcers. Histologically, Cryptococcus is a spherical yeast, often 4 to 20 µm in diameter. Replication is by narrow-based budding. A characteristic feature is a mucoid capsule, which retracts during processing, leaving a clear space around the yeast (Figure 4). When present, the mucoid capsule can be highlighted on mucicarmine or Alcian blue staining. Histologic variants of cryptococcosis include granulomatous (high host immune response), gelatinous (low host immune response), and suppurative types.³  

Blastomycosis
Blastomycosis is caused by Blastomyces dermatitidis, which is endemic in the Midwestern and southeastern United States where it occurs environmentally in wood and soil. Unlike many fungal infections, blastomycosis most often develops in immunocompetent hosts. Infection is usually acquired via inhalation,¹ and cutaneous disease typically is secondary to pulmonary infection. Although not common, traumatic inoculation also can cause cutaneous blastomycosis. Skin lesions include crusted verrucous nodules and plaques with elevated borders.^1,2 Histologic features include pseudoepitheliomatous hyperplasia with intraepidermal neutrophilic microabscesses (Figure 1), and a neutrophilic and granulomatous dermal infiltrate. Organisms often are found within histiocytes (quiz image) or small abscesses. The yeasts usually are 8 to 15 µm in diameter with a thick cell wall and occasionally display broad-based budding.

Chromoblastomycosis is caused by dematiaceous (pigmented) fungi, including Fonsecaea, Phialophora, Cladophialophora, and Rhinocladiella species,³ which are present in soil and vegetable debris in tropical and subtropical regions. Infection typically occurs in the foot or lower leg from traumatic inoculation, such as a thorn or splinter injury.² Histologically, chromoblastomycosis is characterized by pseudoepitheliomatous hyperplasia; suppurative and granulomatous dermatitis; and sclerotic (Medlar) bodies, which are 5 to 12 µm in diameter, round, brown, sometimes septate cells resembling copper pennies (Figure 2).²

Coccidioidomycosis is caused by Coccidioides immitis, which is found in soil in the southwestern United States. Infection most often occurs via inhalation of airborne arthrospores.² Cutaneous lesions occasionally are observed following dissemination or rarely following primary inoculation injury. They may present as papules, nodules, pustules, plaques, and ulcers, with the face being the most commonly affected site.¹ Histologically, coccidioidomycosis is characterized by pseudoepitheliomatous hyperplasia, suppurative and granulomatous dermatitis, and large spherules (up to 100 µm in diameter) containing numerous small endospores (Figure 3).

Cryptococcosis is caused by Cryptococcus neoformans, a fungus found in soil, fruit, and pigeon droppings throughout the world.^2,3 The most common route of infection is via the respiratory tract. Systemic spread and central nervous system involvement may occur in immunocompromised hosts.² Skin involvement is uncommon and may present on the head and neck with umbilicated papules, pustules, nodules, plaques, or ulcers. Histologically, Cryptococcus is a spherical yeast, often 4 to 20 µm in diameter. Replication is by narrow-based budding. A characteristic feature is a mucoid capsule, which retracts during processing, leaving a clear space around the yeast (Figure 4). When present, the mucoid capsule can be highlighted on mucicarmine or Alcian blue staining. Histologic variants of cryptococcosis include granulomatous (high host immune response), gelatinous (low host immune response), and suppurative types.³  

Sea urchin injuries are commonly seen in coastal regions near both warm and cold salt water with frequent recreational water activities or fishing. Sea urchins belong to the class Echinoidea with approximately 600 species, of which roughly 80 are poisonous to humans.^1,2 When a human comes in contact with a sea urchin, the spines of the sea urchin (made of calcium carbonate) can penetrate the skin and break off from the sea urchin, becoming embedded in the skin. Injuries from sea urchin spines are most commonly seen on the hands and feet, as the likelihood of contact with a sea urchin is greater on these sites. The severity of sea urchin spine injuries can vary widely, from minimal local trauma and pain to arthritis, synovitis, and occasionally systemic illness.^1,3 It is important to recognize the wide variety of responses to sea urchin spine injuries and the impact of prompt treatment. Many published reports on injuries from sea urchin spines describe arthritis and synovitis from spines in the joints.^1,2,4-6 Fewer reports discuss nonjoint injuries and the dermatologic aspects of sea urchin spine injuries.^3,7,8 We pre-sent a case of a patient with a puncture injury from sea urchin spines that resulted in painful granulomas.

Case Report

A 29-year-old otherwise healthy man was referred to our dermatology clinic by the university student health center due to continued pain in the right thigh. Five weeks prior to presentation to the student health center, the patient had fallen on a sea urchin while snorkeling in Hawaii. Sea urchin spines became lodged in the right thigh, some of which were removed in a local medical clinic in Hawaii. He was given oral antibiotics prior to his return home. A plain film radiograph of the affected area ordered by the student health center showed several punctate and linear densities in the lateral aspect of the right mid thigh (Figure 1). These findings were consistent with sea urchin spines within the superficial soft tissues of the lateral thigh.

At the time of presentation to our dermatology clinic, the patient reported sharp intermittent pain localized to the right thigh. The patient denied any fever, chills, or pain in the joints. On physical examination, there were several firm nodules on the right thigh, ranging from 4 to 20 mm in diameter (Figure 2). The nodules were tender to palpation with some surrounding edema. Drainage was not noted. Several scars were visible at sites of the original puncture injuries and removal of the spines.

Two 6-mm punch biopsies were performed on representative nodules on the right thigh for histopathologic examination. Along with the biopsy tissue, firm, brown-black, linear foreign bodies consistent with sea urchin spines were extracted with forceps (Figure 3). Histopathologic examination revealed a dense, diffuse, mixed inflammatory cell infiltrate in the dermis predominantly composed of lymphocytes, histiocytes, and numerous eosinophils. Proliferation of small vessels was noted. In one of the biopsies, small fragments of necrotic tissue were present. These findings were consistent with granulomatous inflammation and granulation tissue due to a foreign body.

At the time of suture removal 2 weeks later, the biopsied areas were well healed with minimal erythema. The patient reported decreased pain in the involved areas. He was not seen in clinic again due to resolution of the nodules and associated pain.

Comment

Sea urchin spine injuries are commonly seen in coastal regions with frequent participation in recreational and occupational water activities. A wide variety of responses can be seen in sea urchin spine injuries. There generally are 2 types of cutaneous reaction patterns to sea urchin spines: a primary initial reaction and a secondary delayed/granulomatous reaction. When the spines initially penetrate the skin, the primary initial reaction consists of sharp localized pain that worsens with applied pressure. In addition to pain, bleeding, erythema, edema, and myalgia can occur.³ These symptoms typically subside a few hours after complete removal of the spines from the skin.⁶ If some spines remain in the skin, a secondary delayed/granulomatous reaction can occur, which can lead to the formation of granulomas that can manifest as nodules or papules and can be diffuse.

Many patients may think their painful encounter with a sea urchin was just an unfortunate event, but depending on the location of the injury, more serious extracutaneous reactions and chronic symptoms may occur. Some cases have described the development of arthritis and synovitis from the implantation of spines into joints.^1,2,4-6 Other extracutaneous complications include neuropathy and paresthesia, local bone destruction, radiating pain, muscular weakness, and hypotension.³

The severity of the injury also can depend on the sea urchin species and the number of spines implanted. There are approximately 80 poisonous sea urchin species possessing toxins in venomous spines, resulting in edema and change in the leukocyte-endothelial interaction.⁹ Substances identified in the spines include proteins, steroids, serotonin, histamine, and glycosides.^3,9 The number of spines implanted, particularly the number of venomous spines, can lead to more severe complications. Penetration of 15 or more venomous spines can commonly lead to extracutaneous symptoms.³ Another concern, irrespective of species type, is the potential for secondary infection associated with the spine penetration or implantation into the skin. Mycobacterium marinum infections have been reported in some sea urchin granulomas,¹⁰ as well as fungal infection, bacterial infection, and tetanus.³

The diagnosis of sea urchin spine injuries starts with a thorough history and physical examination. A positive history of sea urchin contact suggests the diagnosis, and radiographs can be useful to find the location of the spine(s), especially if there are no visible nodules on the skin. However, small fragments of spine may not be completely observed on plain radiographs. Any signs or symptoms of infection should prompt a culture for confirmation and guidance for management. Cutaneous biopsies can be helpful for both diagnosis confirmation and symptomatic relief. Reported cases have described granulomatous reactions in the vast majority of the histologic specimens, with necrosis an additional common finding.^7,8 Sea urchin granulomas can be of varying types, the majority being foreign-body and sarcoid types.^3,6,7

Treatment of sea urchin spine injuries primarily involves removal of the spines by a physician. Patients may soak the affected areas in warm water prior to the removal of the spines to aid in pain relief. Surgical removal with local anesthesia and cutaneous extraction is a common treatment method, and more extensive surgical removal of the spines is another option, especially in areas around the joints.² The use of liquid nitrogen or skin punch biopsy also have been described as possible methods to remove the spines.^11,12

Conclusion

Sea urchin spine injuries can result in a wide range of cutaneous and systemic complications. Prompt diagnosis and treatment to remove the sea urchin spines can lessen the associated pain and is important in the prevention of more serious complications.

Sea urchin injuries are commonly seen in coastal regions near both warm and cold salt water with frequent recreational water activities or fishing. Sea urchins belong to the class Echinoidea with approximately 600 species, of which roughly 80 are poisonous to humans.^1,2 When a human comes in contact with a sea urchin, the spines of the sea urchin (made of calcium carbonate) can penetrate the skin and break off from the sea urchin, becoming embedded in the skin. Injuries from sea urchin spines are most commonly seen on the hands and feet, as the likelihood of contact with a sea urchin is greater on these sites. The severity of sea urchin spine injuries can vary widely, from minimal local trauma and pain to arthritis, synovitis, and occasionally systemic illness.^1,3 It is important to recognize the wide variety of responses to sea urchin spine injuries and the impact of prompt treatment. Many published reports on injuries from sea urchin spines describe arthritis and synovitis from spines in the joints.^1,2,4-6 Fewer reports discuss nonjoint injuries and the dermatologic aspects of sea urchin spine injuries.^3,7,8 We pre-sent a case of a patient with a puncture injury from sea urchin spines that resulted in painful granulomas.

Case Report

A 29-year-old otherwise healthy man was referred to our dermatology clinic by the university student health center due to continued pain in the right thigh. Five weeks prior to presentation to the student health center, the patient had fallen on a sea urchin while snorkeling in Hawaii. Sea urchin spines became lodged in the right thigh, some of which were removed in a local medical clinic in Hawaii. He was given oral antibiotics prior to his return home. A plain film radiograph of the affected area ordered by the student health center showed several punctate and linear densities in the lateral aspect of the right mid thigh (Figure 1). These findings were consistent with sea urchin spines within the superficial soft tissues of the lateral thigh.

At the time of presentation to our dermatology clinic, the patient reported sharp intermittent pain localized to the right thigh. The patient denied any fever, chills, or pain in the joints. On physical examination, there were several firm nodules on the right thigh, ranging from 4 to 20 mm in diameter (Figure 2). The nodules were tender to palpation with some surrounding edema. Drainage was not noted. Several scars were visible at sites of the original puncture injuries and removal of the spines.

Two 6-mm punch biopsies were performed on representative nodules on the right thigh for histopathologic examination. Along with the biopsy tissue, firm, brown-black, linear foreign bodies consistent with sea urchin spines were extracted with forceps (Figure 3). Histopathologic examination revealed a dense, diffuse, mixed inflammatory cell infiltrate in the dermis predominantly composed of lymphocytes, histiocytes, and numerous eosinophils. Proliferation of small vessels was noted. In one of the biopsies, small fragments of necrotic tissue were present. These findings were consistent with granulomatous inflammation and granulation tissue due to a foreign body.

At the time of suture removal 2 weeks later, the biopsied areas were well healed with minimal erythema. The patient reported decreased pain in the involved areas. He was not seen in clinic again due to resolution of the nodules and associated pain.

Comment

Sea urchin spine injuries are commonly seen in coastal regions with frequent participation in recreational and occupational water activities. A wide variety of responses can be seen in sea urchin spine injuries. There generally are 2 types of cutaneous reaction patterns to sea urchin spines: a primary initial reaction and a secondary delayed/granulomatous reaction. When the spines initially penetrate the skin, the primary initial reaction consists of sharp localized pain that worsens with applied pressure. In addition to pain, bleeding, erythema, edema, and myalgia can occur.³ These symptoms typically subside a few hours after complete removal of the spines from the skin.⁶ If some spines remain in the skin, a secondary delayed/granulomatous reaction can occur, which can lead to the formation of granulomas that can manifest as nodules or papules and can be diffuse.

Many patients may think their painful encounter with a sea urchin was just an unfortunate event, but depending on the location of the injury, more serious extracutaneous reactions and chronic symptoms may occur. Some cases have described the development of arthritis and synovitis from the implantation of spines into joints.^1,2,4-6 Other extracutaneous complications include neuropathy and paresthesia, local bone destruction, radiating pain, muscular weakness, and hypotension.³

The severity of the injury also can depend on the sea urchin species and the number of spines implanted. There are approximately 80 poisonous sea urchin species possessing toxins in venomous spines, resulting in edema and change in the leukocyte-endothelial interaction.⁹ Substances identified in the spines include proteins, steroids, serotonin, histamine, and glycosides.^3,9 The number of spines implanted, particularly the number of venomous spines, can lead to more severe complications. Penetration of 15 or more venomous spines can commonly lead to extracutaneous symptoms.³ Another concern, irrespective of species type, is the potential for secondary infection associated with the spine penetration or implantation into the skin. Mycobacterium marinum infections have been reported in some sea urchin granulomas,¹⁰ as well as fungal infection, bacterial infection, and tetanus.³

The diagnosis of sea urchin spine injuries starts with a thorough history and physical examination. A positive history of sea urchin contact suggests the diagnosis, and radiographs can be useful to find the location of the spine(s), especially if there are no visible nodules on the skin. However, small fragments of spine may not be completely observed on plain radiographs. Any signs or symptoms of infection should prompt a culture for confirmation and guidance for management. Cutaneous biopsies can be helpful for both diagnosis confirmation and symptomatic relief. Reported cases have described granulomatous reactions in the vast majority of the histologic specimens, with necrosis an additional common finding.^7,8 Sea urchin granulomas can be of varying types, the majority being foreign-body and sarcoid types.^3,6,7

Treatment of sea urchin spine injuries primarily involves removal of the spines by a physician. Patients may soak the affected areas in warm water prior to the removal of the spines to aid in pain relief. Surgical removal with local anesthesia and cutaneous extraction is a common treatment method, and more extensive surgical removal of the spines is another option, especially in areas around the joints.² The use of liquid nitrogen or skin punch biopsy also have been described as possible methods to remove the spines.^11,12

Conclusion

Sea urchin spine injuries can result in a wide range of cutaneous and systemic complications. Prompt diagnosis and treatment to remove the sea urchin spines can lessen the associated pain and is important in the prevention of more serious complications.

Sea urchin injuries are commonly seen in coastal regions near both warm and cold salt water with frequent recreational water activities or fishing. Sea urchins belong to the class Echinoidea with approximately 600 species, of which roughly 80 are poisonous to humans.^1,2 When a human comes in contact with a sea urchin, the spines of the sea urchin (made of calcium carbonate) can penetrate the skin and break off from the sea urchin, becoming embedded in the skin. Injuries from sea urchin spines are most commonly seen on the hands and feet, as the likelihood of contact with a sea urchin is greater on these sites. The severity of sea urchin spine injuries can vary widely, from minimal local trauma and pain to arthritis, synovitis, and occasionally systemic illness.^1,3 It is important to recognize the wide variety of responses to sea urchin spine injuries and the impact of prompt treatment. Many published reports on injuries from sea urchin spines describe arthritis and synovitis from spines in the joints.^1,2,4-6 Fewer reports discuss nonjoint injuries and the dermatologic aspects of sea urchin spine injuries.^3,7,8 We pre-sent a case of a patient with a puncture injury from sea urchin spines that resulted in painful granulomas.

Case Report

A 29-year-old otherwise healthy man was referred to our dermatology clinic by the university student health center due to continued pain in the right thigh. Five weeks prior to presentation to the student health center, the patient had fallen on a sea urchin while snorkeling in Hawaii. Sea urchin spines became lodged in the right thigh, some of which were removed in a local medical clinic in Hawaii. He was given oral antibiotics prior to his return home. A plain film radiograph of the affected area ordered by the student health center showed several punctate and linear densities in the lateral aspect of the right mid thigh (Figure 1). These findings were consistent with sea urchin spines within the superficial soft tissues of the lateral thigh.

At the time of presentation to our dermatology clinic, the patient reported sharp intermittent pain localized to the right thigh. The patient denied any fever, chills, or pain in the joints. On physical examination, there were several firm nodules on the right thigh, ranging from 4 to 20 mm in diameter (Figure 2). The nodules were tender to palpation with some surrounding edema. Drainage was not noted. Several scars were visible at sites of the original puncture injuries and removal of the spines.

Two 6-mm punch biopsies were performed on representative nodules on the right thigh for histopathologic examination. Along with the biopsy tissue, firm, brown-black, linear foreign bodies consistent with sea urchin spines were extracted with forceps (Figure 3). Histopathologic examination revealed a dense, diffuse, mixed inflammatory cell infiltrate in the dermis predominantly composed of lymphocytes, histiocytes, and numerous eosinophils. Proliferation of small vessels was noted. In one of the biopsies, small fragments of necrotic tissue were present. These findings were consistent with granulomatous inflammation and granulation tissue due to a foreign body.

At the time of suture removal 2 weeks later, the biopsied areas were well healed with minimal erythema. The patient reported decreased pain in the involved areas. He was not seen in clinic again due to resolution of the nodules and associated pain.

Comment

Sea urchin spine injuries are commonly seen in coastal regions with frequent participation in recreational and occupational water activities. A wide variety of responses can be seen in sea urchin spine injuries. There generally are 2 types of cutaneous reaction patterns to sea urchin spines: a primary initial reaction and a secondary delayed/granulomatous reaction. When the spines initially penetrate the skin, the primary initial reaction consists of sharp localized pain that worsens with applied pressure. In addition to pain, bleeding, erythema, edema, and myalgia can occur.³ These symptoms typically subside a few hours after complete removal of the spines from the skin.⁶ If some spines remain in the skin, a secondary delayed/granulomatous reaction can occur, which can lead to the formation of granulomas that can manifest as nodules or papules and can be diffuse.

Many patients may think their painful encounter with a sea urchin was just an unfortunate event, but depending on the location of the injury, more serious extracutaneous reactions and chronic symptoms may occur. Some cases have described the development of arthritis and synovitis from the implantation of spines into joints.^1,2,4-6 Other extracutaneous complications include neuropathy and paresthesia, local bone destruction, radiating pain, muscular weakness, and hypotension.³

The severity of the injury also can depend on the sea urchin species and the number of spines implanted. There are approximately 80 poisonous sea urchin species possessing toxins in venomous spines, resulting in edema and change in the leukocyte-endothelial interaction.⁹ Substances identified in the spines include proteins, steroids, serotonin, histamine, and glycosides.^3,9 The number of spines implanted, particularly the number of venomous spines, can lead to more severe complications. Penetration of 15 or more venomous spines can commonly lead to extracutaneous symptoms.³ Another concern, irrespective of species type, is the potential for secondary infection associated with the spine penetration or implantation into the skin. Mycobacterium marinum infections have been reported in some sea urchin granulomas,¹⁰ as well as fungal infection, bacterial infection, and tetanus.³

The diagnosis of sea urchin spine injuries starts with a thorough history and physical examination. A positive history of sea urchin contact suggests the diagnosis, and radiographs can be useful to find the location of the spine(s), especially if there are no visible nodules on the skin. However, small fragments of spine may not be completely observed on plain radiographs. Any signs or symptoms of infection should prompt a culture for confirmation and guidance for management. Cutaneous biopsies can be helpful for both diagnosis confirmation and symptomatic relief. Reported cases have described granulomatous reactions in the vast majority of the histologic specimens, with necrosis an additional common finding.^7,8 Sea urchin granulomas can be of varying types, the majority being foreign-body and sarcoid types.^3,6,7

Treatment of sea urchin spine injuries primarily involves removal of the spines by a physician. Patients may soak the affected areas in warm water prior to the removal of the spines to aid in pain relief. Surgical removal with local anesthesia and cutaneous extraction is a common treatment method, and more extensive surgical removal of the spines is another option, especially in areas around the joints.² The use of liquid nitrogen or skin punch biopsy also have been described as possible methods to remove the spines.^11,12

Conclusion

Sea urchin spine injuries can result in a wide range of cutaneous and systemic complications. Prompt diagnosis and treatment to remove the sea urchin spines can lessen the associated pain and is important in the prevention of more serious complications.

The Diagnosis: Sister Mary Joseph Nodule

The umbilical skin biopsy revealed a moderately differentiated adenocarcinoma (Figure) that was positive for cytokeratin 20 and CDX2 and negative for cytokeratin 7 and transcription termination factor 1. The patient subsequently underwent computed tomography of the abdomen and pelvis, which showed multiple soft-tissue nodules on the greater omentum, a soft-tissue density at the umbilicus, and thickening of the gastric mucosa. An upper endoscopy was then performed, which revealed a large fungating ulcerated mass in the stomach. Biopsy of this mass showed an invasive moderately differentiated adenocarcinoma, which was ERBB2 (formerly HER2) negative. Histopathologically, these pleomorphic glands looked similar to the glands seen in the original skin biopsy. With this diagnosis of metastatic gastric adenocarcinoma, our patient chose palliative chemotherapy but declined precipitously and died 2 months after the initial skin biopsy of the umbilical lesion.

When encountering a patient with an umbilical lesion, it is important to consider benign and malignant lesions in the differential diagnosis. A benign lesion may include scar, cyst, pyogenic granuloma, hemangioma, umbilical hernia, endometriosis, polyp, abscess, or the presence of an omphalith.¹ Inflammatory dermatoses such as psoriasis or eczema also should be considered. Malignant lesions could be either primary or secondary, with metastatic disease being the most common.² Sister Mary Joseph nodule (SMJN) is the eponymgiven to an umbilical lesion representing metastatic disease. Sister Mary Joseph was a nurse and surgical assistant to Dr. William Mayo in Rochester, Minnesota, in what is now known as the Mayo Clinic. She is credited to be the first to observe and note the association between an umbilical nodule and intra-abdominal malignancy. Metastasis to the umbilicus is thought to occur by way of contiguous, hematogenous, lymphatic, or direct spread through embryologic remnants from primary cancers of nearby gastrointestinal or pelvic viscera. It is a rare cutaneous sign of internal malignancy, with an estimated prevalence of 1% to 3%.³ The most common primary cancer is gastric adenocarcinoma, though cases of metastasis from pancreatic, endometrial, and less commonly hematopoietic or supradiaphragmatic cancers have been reported.⁴ It is more common in women, likely due to the addition of gynecologic malignancies.¹

The use of dermoscopy has been advocated as an adjuvant tool in delineating benign and malignant umbilical lesions when an atypical polymorphous vascular pattern indicating neovascularization has been observed with neoplastic growth.⁵ Once a suspicious umbilical lesion is identified, the first step should be to obtain a skin biopsy or to use fine needle aspiration for cytology.⁶ Biopsy is especially relevant in the background of cancer history because SMJN may present with cancer recurrence.3 Once one of these is obtained, histological and immunohistochemical analysis will guide further workup and diagnosis of the umbilical lesion.

The importance of reviewing such cases lies in the variable presentation of cutaneous metastases such as SMJN and the grim prognosis that accompanies this finding. It presents as a firm indurated plaque or nodule that may present with systemic symptoms suggestive of malignancy, though in 30% of cases it is the sole initial sign.⁷ The nodule may be painful if ulcerated or fissured. Bloody, serous, or purulent discharge may be present. After diagnosis of an SMJN, most patients succumb to the disease within 12 months. Thus, it is vital for dermatologists to investigate umbilical lesions with great caution and a high index of suspicion.

The Diagnosis: Sister Mary Joseph Nodule

The umbilical skin biopsy revealed a moderately differentiated adenocarcinoma (Figure) that was positive for cytokeratin 20 and CDX2 and negative for cytokeratin 7 and transcription termination factor 1. The patient subsequently underwent computed tomography of the abdomen and pelvis, which showed multiple soft-tissue nodules on the greater omentum, a soft-tissue density at the umbilicus, and thickening of the gastric mucosa. An upper endoscopy was then performed, which revealed a large fungating ulcerated mass in the stomach. Biopsy of this mass showed an invasive moderately differentiated adenocarcinoma, which was ERBB2 (formerly HER2) negative. Histopathologically, these pleomorphic glands looked similar to the glands seen in the original skin biopsy. With this diagnosis of metastatic gastric adenocarcinoma, our patient chose palliative chemotherapy but declined precipitously and died 2 months after the initial skin biopsy of the umbilical lesion.

When encountering a patient with an umbilical lesion, it is important to consider benign and malignant lesions in the differential diagnosis. A benign lesion may include scar, cyst, pyogenic granuloma, hemangioma, umbilical hernia, endometriosis, polyp, abscess, or the presence of an omphalith.¹ Inflammatory dermatoses such as psoriasis or eczema also should be considered. Malignant lesions could be either primary or secondary, with metastatic disease being the most common.² Sister Mary Joseph nodule (SMJN) is the eponymgiven to an umbilical lesion representing metastatic disease. Sister Mary Joseph was a nurse and surgical assistant to Dr. William Mayo in Rochester, Minnesota, in what is now known as the Mayo Clinic. She is credited to be the first to observe and note the association between an umbilical nodule and intra-abdominal malignancy. Metastasis to the umbilicus is thought to occur by way of contiguous, hematogenous, lymphatic, or direct spread through embryologic remnants from primary cancers of nearby gastrointestinal or pelvic viscera. It is a rare cutaneous sign of internal malignancy, with an estimated prevalence of 1% to 3%.³ The most common primary cancer is gastric adenocarcinoma, though cases of metastasis from pancreatic, endometrial, and less commonly hematopoietic or supradiaphragmatic cancers have been reported.⁴ It is more common in women, likely due to the addition of gynecologic malignancies.¹

The use of dermoscopy has been advocated as an adjuvant tool in delineating benign and malignant umbilical lesions when an atypical polymorphous vascular pattern indicating neovascularization has been observed with neoplastic growth.⁵ Once a suspicious umbilical lesion is identified, the first step should be to obtain a skin biopsy or to use fine needle aspiration for cytology.⁶ Biopsy is especially relevant in the background of cancer history because SMJN may present with cancer recurrence.3 Once one of these is obtained, histological and immunohistochemical analysis will guide further workup and diagnosis of the umbilical lesion.

The importance of reviewing such cases lies in the variable presentation of cutaneous metastases such as SMJN and the grim prognosis that accompanies this finding. It presents as a firm indurated plaque or nodule that may present with systemic symptoms suggestive of malignancy, though in 30% of cases it is the sole initial sign.⁷ The nodule may be painful if ulcerated or fissured. Bloody, serous, or purulent discharge may be present. After diagnosis of an SMJN, most patients succumb to the disease within 12 months. Thus, it is vital for dermatologists to investigate umbilical lesions with great caution and a high index of suspicion.

The Diagnosis: Sister Mary Joseph Nodule

The umbilical skin biopsy revealed a moderately differentiated adenocarcinoma (Figure) that was positive for cytokeratin 20 and CDX2 and negative for cytokeratin 7 and transcription termination factor 1. The patient subsequently underwent computed tomography of the abdomen and pelvis, which showed multiple soft-tissue nodules on the greater omentum, a soft-tissue density at the umbilicus, and thickening of the gastric mucosa. An upper endoscopy was then performed, which revealed a large fungating ulcerated mass in the stomach. Biopsy of this mass showed an invasive moderately differentiated adenocarcinoma, which was ERBB2 (formerly HER2) negative. Histopathologically, these pleomorphic glands looked similar to the glands seen in the original skin biopsy. With this diagnosis of metastatic gastric adenocarcinoma, our patient chose palliative chemotherapy but declined precipitously and died 2 months after the initial skin biopsy of the umbilical lesion.

When encountering a patient with an umbilical lesion, it is important to consider benign and malignant lesions in the differential diagnosis. A benign lesion may include scar, cyst, pyogenic granuloma, hemangioma, umbilical hernia, endometriosis, polyp, abscess, or the presence of an omphalith.¹ Inflammatory dermatoses such as psoriasis or eczema also should be considered. Malignant lesions could be either primary or secondary, with metastatic disease being the most common.² Sister Mary Joseph nodule (SMJN) is the eponymgiven to an umbilical lesion representing metastatic disease. Sister Mary Joseph was a nurse and surgical assistant to Dr. William Mayo in Rochester, Minnesota, in what is now known as the Mayo Clinic. She is credited to be the first to observe and note the association between an umbilical nodule and intra-abdominal malignancy. Metastasis to the umbilicus is thought to occur by way of contiguous, hematogenous, lymphatic, or direct spread through embryologic remnants from primary cancers of nearby gastrointestinal or pelvic viscera. It is a rare cutaneous sign of internal malignancy, with an estimated prevalence of 1% to 3%.³ The most common primary cancer is gastric adenocarcinoma, though cases of metastasis from pancreatic, endometrial, and less commonly hematopoietic or supradiaphragmatic cancers have been reported.⁴ It is more common in women, likely due to the addition of gynecologic malignancies.¹

The use of dermoscopy has been advocated as an adjuvant tool in delineating benign and malignant umbilical lesions when an atypical polymorphous vascular pattern indicating neovascularization has been observed with neoplastic growth.⁵ Once a suspicious umbilical lesion is identified, the first step should be to obtain a skin biopsy or to use fine needle aspiration for cytology.⁶ Biopsy is especially relevant in the background of cancer history because SMJN may present with cancer recurrence.3 Once one of these is obtained, histological and immunohistochemical analysis will guide further workup and diagnosis of the umbilical lesion.

The importance of reviewing such cases lies in the variable presentation of cutaneous metastases such as SMJN and the grim prognosis that accompanies this finding. It presents as a firm indurated plaque or nodule that may present with systemic symptoms suggestive of malignancy, though in 30% of cases it is the sole initial sign.⁷ The nodule may be painful if ulcerated or fissured. Bloody, serous, or purulent discharge may be present. After diagnosis of an SMJN, most patients succumb to the disease within 12 months. Thus, it is vital for dermatologists to investigate umbilical lesions with great caution and a high index of suspicion.

The Diagnosis: Lichen Striatus

Lichen striatus (LS) is an acquired and self-limited linear inflammatory dermatosis that most frequently occurs in children and less commonly in adults.^1-3 Clinically, it is characterized by the sudden onset of an eruption consisting of slightly pigmented, erythematous, flat-topped papules with minimal scaling. These papules quickly coalesce to form a linear band that extends along a limb, the trunk, or the face, within Blaschko lines.^1,4 In the adult form, patients tend to experience more diffuse lesions as well as severe pruritus with higher rates of relapse. It occasionally manifests in a dermatomal manner.¹ 

The differential diagnosis includes other linear acquired inflammatory dermatoses such as blaschkitis, lichen planus, inflammatory linear verrucous epidermal nevus, and psoriasis. Blaschkitis has been described as a rare dermatosis that occurs along the Blaschko lines, affecting adults preferentially over children. Controversy exists whether blaschkitis and lichen striatus are the same disease or 2 separate entities.⁵ Clinically, both blaschkitis and lichen striatus can present with multiple linear papules and vesicles predominantly on the trunk. In blaschkitis, there is a predilection for males, with an older mean age at onset of 40 years.⁵ Lesions quickly resolve over months with frequent relapse compared to lichen striatus, which can persist for months to years. 

Histopathologically, blaschkitis demonstrates spongiosis, usually without involvement of the adnexal structures. Lichenoid and spongiotic changes with adnexal extension are the hallmark features of lichen striatus. In our patient, biopsy showed several dense bandlike foci of lymphohistiocytic infiltrates along the dermoepidermal junction with spongiosis, basal cell liquefactive degeneration, and pigmentary incontinence (Figure 1). The focal areas were surfaced by parakeratotic and orthohyperkeratotic scale. Deep dermal perivascular and periadnexal extension was present (Figure 2). Periodic acid-Schiff stain was negative for fungi.

The pathogenesis of lichen striatus is not entirely understood, but it has been postulated that trauma, vaccinations, or viral infections may induce loss of immunologic tolerance to keratinocytes.¹ This loss of tolerance can result in a T cell-mediated autoimmune reaction against malpighian cells, which show genetic mosaicism and are arranged along Blaschko lines.^1,3 Familial cases also have been reported, suggesting that there may be an epigenetic mosaicism that contributes to this group of skin diseases.^6,7

Lichen striatus tends to resolve on its own after approximately 6 to 9 months.⁸ Treatment typically consists of application of topical corticosteroids.¹ Cases also have been successfully treated with tacrolimus and pimecrolimus.^1,8 Our patient was treated with a midpotency topical steroid with improvement of the appearance but not complete resolution.

The Diagnosis: Lichen Striatus

Lichen striatus (LS) is an acquired and self-limited linear inflammatory dermatosis that most frequently occurs in children and less commonly in adults.^1-3 Clinically, it is characterized by the sudden onset of an eruption consisting of slightly pigmented, erythematous, flat-topped papules with minimal scaling. These papules quickly coalesce to form a linear band that extends along a limb, the trunk, or the face, within Blaschko lines.^1,4 In the adult form, patients tend to experience more diffuse lesions as well as severe pruritus with higher rates of relapse. It occasionally manifests in a dermatomal manner.¹ 

The differential diagnosis includes other linear acquired inflammatory dermatoses such as blaschkitis, lichen planus, inflammatory linear verrucous epidermal nevus, and psoriasis. Blaschkitis has been described as a rare dermatosis that occurs along the Blaschko lines, affecting adults preferentially over children. Controversy exists whether blaschkitis and lichen striatus are the same disease or 2 separate entities.⁵ Clinically, both blaschkitis and lichen striatus can present with multiple linear papules and vesicles predominantly on the trunk. In blaschkitis, there is a predilection for males, with an older mean age at onset of 40 years.⁵ Lesions quickly resolve over months with frequent relapse compared to lichen striatus, which can persist for months to years. 

Histopathologically, blaschkitis demonstrates spongiosis, usually without involvement of the adnexal structures. Lichenoid and spongiotic changes with adnexal extension are the hallmark features of lichen striatus. In our patient, biopsy showed several dense bandlike foci of lymphohistiocytic infiltrates along the dermoepidermal junction with spongiosis, basal cell liquefactive degeneration, and pigmentary incontinence (Figure 1). The focal areas were surfaced by parakeratotic and orthohyperkeratotic scale. Deep dermal perivascular and periadnexal extension was present (Figure 2). Periodic acid-Schiff stain was negative for fungi.

The pathogenesis of lichen striatus is not entirely understood, but it has been postulated that trauma, vaccinations, or viral infections may induce loss of immunologic tolerance to keratinocytes.¹ This loss of tolerance can result in a T cell-mediated autoimmune reaction against malpighian cells, which show genetic mosaicism and are arranged along Blaschko lines.^1,3 Familial cases also have been reported, suggesting that there may be an epigenetic mosaicism that contributes to this group of skin diseases.^6,7

Lichen striatus tends to resolve on its own after approximately 6 to 9 months.⁸ Treatment typically consists of application of topical corticosteroids.¹ Cases also have been successfully treated with tacrolimus and pimecrolimus.^1,8 Our patient was treated with a midpotency topical steroid with improvement of the appearance but not complete resolution.

The Diagnosis: Lichen Striatus

Lichen striatus (LS) is an acquired and self-limited linear inflammatory dermatosis that most frequently occurs in children and less commonly in adults.^1-3 Clinically, it is characterized by the sudden onset of an eruption consisting of slightly pigmented, erythematous, flat-topped papules with minimal scaling. These papules quickly coalesce to form a linear band that extends along a limb, the trunk, or the face, within Blaschko lines.^1,4 In the adult form, patients tend to experience more diffuse lesions as well as severe pruritus with higher rates of relapse. It occasionally manifests in a dermatomal manner.¹ 

The differential diagnosis includes other linear acquired inflammatory dermatoses such as blaschkitis, lichen planus, inflammatory linear verrucous epidermal nevus, and psoriasis. Blaschkitis has been described as a rare dermatosis that occurs along the Blaschko lines, affecting adults preferentially over children. Controversy exists whether blaschkitis and lichen striatus are the same disease or 2 separate entities.⁵ Clinically, both blaschkitis and lichen striatus can present with multiple linear papules and vesicles predominantly on the trunk. In blaschkitis, there is a predilection for males, with an older mean age at onset of 40 years.⁵ Lesions quickly resolve over months with frequent relapse compared to lichen striatus, which can persist for months to years. 

Histopathologically, blaschkitis demonstrates spongiosis, usually without involvement of the adnexal structures. Lichenoid and spongiotic changes with adnexal extension are the hallmark features of lichen striatus. In our patient, biopsy showed several dense bandlike foci of lymphohistiocytic infiltrates along the dermoepidermal junction with spongiosis, basal cell liquefactive degeneration, and pigmentary incontinence (Figure 1). The focal areas were surfaced by parakeratotic and orthohyperkeratotic scale. Deep dermal perivascular and periadnexal extension was present (Figure 2). Periodic acid-Schiff stain was negative for fungi.

The pathogenesis of lichen striatus is not entirely understood, but it has been postulated that trauma, vaccinations, or viral infections may induce loss of immunologic tolerance to keratinocytes.¹ This loss of tolerance can result in a T cell-mediated autoimmune reaction against malpighian cells, which show genetic mosaicism and are arranged along Blaschko lines.^1,3 Familial cases also have been reported, suggesting that there may be an epigenetic mosaicism that contributes to this group of skin diseases.^6,7

Lichen striatus tends to resolve on its own after approximately 6 to 9 months.⁸ Treatment typically consists of application of topical corticosteroids.¹ Cases also have been successfully treated with tacrolimus and pimecrolimus.^1,8 Our patient was treated with a midpotency topical steroid with improvement of the appearance but not complete resolution.