Donna Tran, DO

Perniosis, or chilblain, is characterized by localized, tender, erythematous skin lesions that occur as an abnormal reaction to exposure to cold and damp conditions. Although the lesions favor the distal extremities, perniosis may present anywhere on the body. Lesions can develop within hours to days following exposure to temperature less than 10°C or damp environments with greater than 60% humidity.¹ Acute cases may lead to pruritus and tenderness, whereas chronic cases may involve lesions that blister or ulcerate and can take weeks to heal. We report an unusual case of erythematous plaques arising on the buttocks of a 73-year-old woman using ice pack treatments for chronic low back pain.

Case Report

A 73-year-old woman presented with recurrent tender lesions on the buttocks of 5 years’ duration. Her medical history was remarkable for hypertension, hypothyroidism, and lumbar spinal fusion surgery 5 years prior. Physical examination revealed indurated erythematous plaques with areas of erosions on the left buttock with some involvement of the right buttock (Figure 1).

After a trial of oral valacyclovir for presumed herpes simplex infection provided no relief, a punch biopsy of the left buttock was performed, which revealed a cell-poor interface dermatitis with superficial and deep perivascular and periadnexal lymphocytic infiltrates (Figure 2). Perieccrine lymphocytes were present in a small portion of the reticular dermis (Figure 3). The patient revealed she had been sitting on ice packs for several hours daily since the lumbar spinal fusion surgery 5 years prior to alleviate chronic low back pain.

Based on the clinicopathologic correlation, a diagnosis of perniosis secondary to ice pack therapy was made. An evaluation for concomitant or underlying connective tissue disease (CTD) including a complete blood cell count with sedimentation rate, antinuclear antibodies (ANAs), serum protein electrophoresis, and serum levels of cryoglobulins and complement components was unremarkable. Our patient was treated with simple analgesia and was encouraged to avoid direct contact with ice packs for extended periods of time. Because of her low back pain, she continued to use ice packs but readjusted them sporadically and decreased frequency of use. She had complete resolution of the lesions at 6-month follow-up.

Comment

Perniosis is a self-limited condition, manifesting as erythematous plaques or nodules following exposure to cold and damp conditions. It was first reported in 1902 by Hochsinger² as tender submental plaques occurring in children after exposure to cold weather. Since then, reports of perniosis have been described in equestrians and long-distance cyclists as well as in the context of other outdoor activities.^3-5 In all cases, patients developed perniosis at sites of exposure to cold or damp conditions.

Perniosis arising in patients using ice pack therapy is a rare and recent phenomenon, with only 3 other known reported cases.^6,7 In all cases, including ours, patients reported treating chronic low back pain with ice packs for more than 2 hours per day. Clinical presentations included erythematous to purpuric plaques with ulceration on the lower back or buttocks that reoccurred with subsequent use of ice packs. No concomitant CTD was reported.⁶

Much controversy exists as to whether idiopathic perniosis (IP) increases susceptibility to acquiring an autoimmune disease or if IP is a form of CTD that follows a more indolent course.⁸ In a prospective study of 33 patients with underlying IP, no patients developed lupus erythematosus (LE), with a median follow-up of 38 months.⁹ A study by Crowson and Magro⁸ revealed that 18 of 39 patients with perniotic lesions had an associated systemic disease including LE, human immunodeficiency virus, viral hepatitis, rheumatoid arthritis, cryofibrinogenemia, hypergammaglobulinemia, iritis, or Crohn disease. Of the 21 other patients who had no underlying CTD or systemic disease, 10 had a positive ANA test but no systemic symptoms; therefore, all 21 of these patients were classified as cases of IP.⁸

Cutaneous biopsy to distinguish between IP and autoimmune perniosis remains controversial; perniotic lesions and discoid LE share histopathologic features,⁹ as was evident with our case, which demonstrated overlapping findings of vacuolar change with superficial and deep perivascular and periadnexal lymphoid infiltrates. Typical features of IP include thrombosed capillaries in the papillary dermis and lymphocytic exocytosis localized to the acrosyringia, whereas secondary perniosis has superficial and deep perivascular and perieccrine lymphocytic infiltrates with vascular thrombosis in the reticular dermis. Vascular ectasia, dermal mucinosis, basement membrane zone thickening, and erythrocyte extravasation are not reliable and may be seen in both cases.⁸ One study revealed the only significant difference between both entities was the perieccrine distribution of lymphocytic infiltrate in cases of IP (P=.007), whereas an absence of perieccrine involvement was noted in autoimmune cases.⁹

Direct immunofluorescence (DIF) may help differentiate IP from autoimmune perniosis. In a prospective study by Viguier et al,⁹ 6 of 9 patients with IP had negative DIF and 3 had slight nonspecific C3 immunoreactivity of dermal vessels. Conversely, in patients with autoimmune perniosis, positive DIF with the lupus band test was seen in 3 of 7 patients, all who had a positive ANA test⁹; however, positive ANA levels also were reported in patients with autoimmune perniosis but negative DIF, suggesting that DIF lacks specificity in diagnosing autoimmune perniosis.

Although histopathologic findings bear similarities to LE, there are no guidelines to suggest for or against laboratory testing for CTD in patients presenting with perniosis. Some investigators have suggested that any patient with clinical features suggestive of perniosis should undergo laboratory evaluation including a complete blood cell count and assessment for antibodies to Ro, ANA, rheumatoid factor, cryofibrinogens, and antiphospholipid antibodies.⁹ Serum protein electrophoresis and immunofixation electrophoresis may be done to exclude monoclonal gammopathy.

For idiopathic cases, treatment is aimed at limiting or removing cold exposure. Patients should be advised regarding the use of long-term ice pack use and the potential development of perniosis. For chronic perniosis lasting beyond several weeks, a combination of a slow taper of oral prednisone, hydroxychloroquine, and quinacrine has been successful in patients with persistent lesions despite making environmental modifications.³ Intralesional triamcinolone acetonide and nifedipine also have been effective in perniotic hand lesions.¹⁰

Conclusion

We report a rare case of perniosis on the buttocks that arose in a patient who utilized ice packs for treatment of chronic low back pain. Ice pack–induced perniosis may be an underreported entity. Histopathologic examination is nondescript, as overlapping features of perniosis and LE have been observed with no underlying CTD present. Correlation with patient history and clinical examination is paramount in diagnosis and management.

Perniosis, or chilblain, is characterized by localized, tender, erythematous skin lesions that occur as an abnormal reaction to exposure to cold and damp conditions. Although the lesions favor the distal extremities, perniosis may present anywhere on the body. Lesions can develop within hours to days following exposure to temperature less than 10°C or damp environments with greater than 60% humidity.¹ Acute cases may lead to pruritus and tenderness, whereas chronic cases may involve lesions that blister or ulcerate and can take weeks to heal. We report an unusual case of erythematous plaques arising on the buttocks of a 73-year-old woman using ice pack treatments for chronic low back pain.

Case Report

A 73-year-old woman presented with recurrent tender lesions on the buttocks of 5 years’ duration. Her medical history was remarkable for hypertension, hypothyroidism, and lumbar spinal fusion surgery 5 years prior. Physical examination revealed indurated erythematous plaques with areas of erosions on the left buttock with some involvement of the right buttock (Figure 1).

After a trial of oral valacyclovir for presumed herpes simplex infection provided no relief, a punch biopsy of the left buttock was performed, which revealed a cell-poor interface dermatitis with superficial and deep perivascular and periadnexal lymphocytic infiltrates (Figure 2). Perieccrine lymphocytes were present in a small portion of the reticular dermis (Figure 3). The patient revealed she had been sitting on ice packs for several hours daily since the lumbar spinal fusion surgery 5 years prior to alleviate chronic low back pain.

Based on the clinicopathologic correlation, a diagnosis of perniosis secondary to ice pack therapy was made. An evaluation for concomitant or underlying connective tissue disease (CTD) including a complete blood cell count with sedimentation rate, antinuclear antibodies (ANAs), serum protein electrophoresis, and serum levels of cryoglobulins and complement components was unremarkable. Our patient was treated with simple analgesia and was encouraged to avoid direct contact with ice packs for extended periods of time. Because of her low back pain, she continued to use ice packs but readjusted them sporadically and decreased frequency of use. She had complete resolution of the lesions at 6-month follow-up.

Comment

Perniosis is a self-limited condition, manifesting as erythematous plaques or nodules following exposure to cold and damp conditions. It was first reported in 1902 by Hochsinger² as tender submental plaques occurring in children after exposure to cold weather. Since then, reports of perniosis have been described in equestrians and long-distance cyclists as well as in the context of other outdoor activities.^3-5 In all cases, patients developed perniosis at sites of exposure to cold or damp conditions.

Perniosis arising in patients using ice pack therapy is a rare and recent phenomenon, with only 3 other known reported cases.^6,7 In all cases, including ours, patients reported treating chronic low back pain with ice packs for more than 2 hours per day. Clinical presentations included erythematous to purpuric plaques with ulceration on the lower back or buttocks that reoccurred with subsequent use of ice packs. No concomitant CTD was reported.⁶

Much controversy exists as to whether idiopathic perniosis (IP) increases susceptibility to acquiring an autoimmune disease or if IP is a form of CTD that follows a more indolent course.⁸ In a prospective study of 33 patients with underlying IP, no patients developed lupus erythematosus (LE), with a median follow-up of 38 months.⁹ A study by Crowson and Magro⁸ revealed that 18 of 39 patients with perniotic lesions had an associated systemic disease including LE, human immunodeficiency virus, viral hepatitis, rheumatoid arthritis, cryofibrinogenemia, hypergammaglobulinemia, iritis, or Crohn disease. Of the 21 other patients who had no underlying CTD or systemic disease, 10 had a positive ANA test but no systemic symptoms; therefore, all 21 of these patients were classified as cases of IP.⁸

Cutaneous biopsy to distinguish between IP and autoimmune perniosis remains controversial; perniotic lesions and discoid LE share histopathologic features,⁹ as was evident with our case, which demonstrated overlapping findings of vacuolar change with superficial and deep perivascular and periadnexal lymphoid infiltrates. Typical features of IP include thrombosed capillaries in the papillary dermis and lymphocytic exocytosis localized to the acrosyringia, whereas secondary perniosis has superficial and deep perivascular and perieccrine lymphocytic infiltrates with vascular thrombosis in the reticular dermis. Vascular ectasia, dermal mucinosis, basement membrane zone thickening, and erythrocyte extravasation are not reliable and may be seen in both cases.⁸ One study revealed the only significant difference between both entities was the perieccrine distribution of lymphocytic infiltrate in cases of IP (P=.007), whereas an absence of perieccrine involvement was noted in autoimmune cases.⁹

Direct immunofluorescence (DIF) may help differentiate IP from autoimmune perniosis. In a prospective study by Viguier et al,⁹ 6 of 9 patients with IP had negative DIF and 3 had slight nonspecific C3 immunoreactivity of dermal vessels. Conversely, in patients with autoimmune perniosis, positive DIF with the lupus band test was seen in 3 of 7 patients, all who had a positive ANA test⁹; however, positive ANA levels also were reported in patients with autoimmune perniosis but negative DIF, suggesting that DIF lacks specificity in diagnosing autoimmune perniosis.

Although histopathologic findings bear similarities to LE, there are no guidelines to suggest for or against laboratory testing for CTD in patients presenting with perniosis. Some investigators have suggested that any patient with clinical features suggestive of perniosis should undergo laboratory evaluation including a complete blood cell count and assessment for antibodies to Ro, ANA, rheumatoid factor, cryofibrinogens, and antiphospholipid antibodies.⁹ Serum protein electrophoresis and immunofixation electrophoresis may be done to exclude monoclonal gammopathy.

For idiopathic cases, treatment is aimed at limiting or removing cold exposure. Patients should be advised regarding the use of long-term ice pack use and the potential development of perniosis. For chronic perniosis lasting beyond several weeks, a combination of a slow taper of oral prednisone, hydroxychloroquine, and quinacrine has been successful in patients with persistent lesions despite making environmental modifications.³ Intralesional triamcinolone acetonide and nifedipine also have been effective in perniotic hand lesions.¹⁰

Conclusion

We report a rare case of perniosis on the buttocks that arose in a patient who utilized ice packs for treatment of chronic low back pain. Ice pack–induced perniosis may be an underreported entity. Histopathologic examination is nondescript, as overlapping features of perniosis and LE have been observed with no underlying CTD present. Correlation with patient history and clinical examination is paramount in diagnosis and management.

Perniosis, or chilblain, is characterized by localized, tender, erythematous skin lesions that occur as an abnormal reaction to exposure to cold and damp conditions. Although the lesions favor the distal extremities, perniosis may present anywhere on the body. Lesions can develop within hours to days following exposure to temperature less than 10°C or damp environments with greater than 60% humidity.¹ Acute cases may lead to pruritus and tenderness, whereas chronic cases may involve lesions that blister or ulcerate and can take weeks to heal. We report an unusual case of erythematous plaques arising on the buttocks of a 73-year-old woman using ice pack treatments for chronic low back pain.

Case Report

A 73-year-old woman presented with recurrent tender lesions on the buttocks of 5 years’ duration. Her medical history was remarkable for hypertension, hypothyroidism, and lumbar spinal fusion surgery 5 years prior. Physical examination revealed indurated erythematous plaques with areas of erosions on the left buttock with some involvement of the right buttock (Figure 1).

After a trial of oral valacyclovir for presumed herpes simplex infection provided no relief, a punch biopsy of the left buttock was performed, which revealed a cell-poor interface dermatitis with superficial and deep perivascular and periadnexal lymphocytic infiltrates (Figure 2). Perieccrine lymphocytes were present in a small portion of the reticular dermis (Figure 3). The patient revealed she had been sitting on ice packs for several hours daily since the lumbar spinal fusion surgery 5 years prior to alleviate chronic low back pain.

Based on the clinicopathologic correlation, a diagnosis of perniosis secondary to ice pack therapy was made. An evaluation for concomitant or underlying connective tissue disease (CTD) including a complete blood cell count with sedimentation rate, antinuclear antibodies (ANAs), serum protein electrophoresis, and serum levels of cryoglobulins and complement components was unremarkable. Our patient was treated with simple analgesia and was encouraged to avoid direct contact with ice packs for extended periods of time. Because of her low back pain, she continued to use ice packs but readjusted them sporadically and decreased frequency of use. She had complete resolution of the lesions at 6-month follow-up.

Comment

Perniosis is a self-limited condition, manifesting as erythematous plaques or nodules following exposure to cold and damp conditions. It was first reported in 1902 by Hochsinger² as tender submental plaques occurring in children after exposure to cold weather. Since then, reports of perniosis have been described in equestrians and long-distance cyclists as well as in the context of other outdoor activities.^3-5 In all cases, patients developed perniosis at sites of exposure to cold or damp conditions.

Perniosis arising in patients using ice pack therapy is a rare and recent phenomenon, with only 3 other known reported cases.^6,7 In all cases, including ours, patients reported treating chronic low back pain with ice packs for more than 2 hours per day. Clinical presentations included erythematous to purpuric plaques with ulceration on the lower back or buttocks that reoccurred with subsequent use of ice packs. No concomitant CTD was reported.⁶

Much controversy exists as to whether idiopathic perniosis (IP) increases susceptibility to acquiring an autoimmune disease or if IP is a form of CTD that follows a more indolent course.⁸ In a prospective study of 33 patients with underlying IP, no patients developed lupus erythematosus (LE), with a median follow-up of 38 months.⁹ A study by Crowson and Magro⁸ revealed that 18 of 39 patients with perniotic lesions had an associated systemic disease including LE, human immunodeficiency virus, viral hepatitis, rheumatoid arthritis, cryofibrinogenemia, hypergammaglobulinemia, iritis, or Crohn disease. Of the 21 other patients who had no underlying CTD or systemic disease, 10 had a positive ANA test but no systemic symptoms; therefore, all 21 of these patients were classified as cases of IP.⁸

Cutaneous biopsy to distinguish between IP and autoimmune perniosis remains controversial; perniotic lesions and discoid LE share histopathologic features,⁹ as was evident with our case, which demonstrated overlapping findings of vacuolar change with superficial and deep perivascular and periadnexal lymphoid infiltrates. Typical features of IP include thrombosed capillaries in the papillary dermis and lymphocytic exocytosis localized to the acrosyringia, whereas secondary perniosis has superficial and deep perivascular and perieccrine lymphocytic infiltrates with vascular thrombosis in the reticular dermis. Vascular ectasia, dermal mucinosis, basement membrane zone thickening, and erythrocyte extravasation are not reliable and may be seen in both cases.⁸ One study revealed the only significant difference between both entities was the perieccrine distribution of lymphocytic infiltrate in cases of IP (P=.007), whereas an absence of perieccrine involvement was noted in autoimmune cases.⁹

Direct immunofluorescence (DIF) may help differentiate IP from autoimmune perniosis. In a prospective study by Viguier et al,⁹ 6 of 9 patients with IP had negative DIF and 3 had slight nonspecific C3 immunoreactivity of dermal vessels. Conversely, in patients with autoimmune perniosis, positive DIF with the lupus band test was seen in 3 of 7 patients, all who had a positive ANA test⁹; however, positive ANA levels also were reported in patients with autoimmune perniosis but negative DIF, suggesting that DIF lacks specificity in diagnosing autoimmune perniosis.

Although histopathologic findings bear similarities to LE, there are no guidelines to suggest for or against laboratory testing for CTD in patients presenting with perniosis. Some investigators have suggested that any patient with clinical features suggestive of perniosis should undergo laboratory evaluation including a complete blood cell count and assessment for antibodies to Ro, ANA, rheumatoid factor, cryofibrinogens, and antiphospholipid antibodies.⁹ Serum protein electrophoresis and immunofixation electrophoresis may be done to exclude monoclonal gammopathy.

For idiopathic cases, treatment is aimed at limiting or removing cold exposure. Patients should be advised regarding the use of long-term ice pack use and the potential development of perniosis. For chronic perniosis lasting beyond several weeks, a combination of a slow taper of oral prednisone, hydroxychloroquine, and quinacrine has been successful in patients with persistent lesions despite making environmental modifications.³ Intralesional triamcinolone acetonide and nifedipine also have been effective in perniotic hand lesions.¹⁰

Conclusion

We report a rare case of perniosis on the buttocks that arose in a patient who utilized ice packs for treatment of chronic low back pain. Ice pack–induced perniosis may be an underreported entity. Histopathologic examination is nondescript, as overlapping features of perniosis and LE have been observed with no underlying CTD present. Correlation with patient history and clinical examination is paramount in diagnosis and management.

Fibrofolliculomas and trichodiscomas typically present on the head or neck as smooth, flesh-colored, dome-shaped papules. These two entities are considered to constitute two separate time points on a spectrum of histopathologic changes in mantleoma differentiation.¹ Histologically, both are benign hamartomas of the pilosebaceous subunit and collectively are known as mantleomas. We present an unusual case of a concomitant fibrofolliculoma and trichodiscoma on the abdomen.

Case Report

An asymptomatic 54-year-old man presented for a routine full-body skin examination. A solitary, 2×1-cm, subcutaneous, doughy, mobile nodule was found on the left side of the abdomen with an overlying 2-mm yellow fleshy papule. The patient declined excision of the lesion, and it was recommended that he return for follow-up 3 months later.

The patient did not present for follow-up until 4.5 years later, at which point the lesion had grown to 3.0×2.5 cm in size. An excision was performed, at which time the lesion was noted to be cystic, extruding an oily, yellow-white liquid. Bacterial culture was negative. Histopathologic sections showed a dome-shaped papule with connection to the overlying epidermis. Epithelial extensions from the infundibular epithelium formed a fenestrated pattern surrounding a fibrous and mucinous stroma (Figure, A and B). The differential diagnosis at this time included an epidermal inclusion cyst, fibroma, intradermal nevus, verruca, hemangioma, angiofibroma, and lipoma.^2-4

The same lesion cut in a different plane of sectioning showed an expansile dermal nodule comprising clusters of sebaceous lobules surrounding a fibrous and mucinous stroma. Within the second lesion, fibrous and stromal components predominated over epithelial components (Figure, C). A diagnosis of fibrofolliculoma showing features of a trichodiscoma arising in the unusual location of the abdomen was made.

Comment

Solitary fibrofolliculomas and trichodiscomas are flesh-colored, dome-shaped papules that generally present on the face, specifically on the chin, nose, cheeks, ears, and eyebrows without considerable symptoms.^2,4,5 Clinically, fibrofolliculomas are indistinguishable from trichodiscomas but demonstrate different features on biopsy.^1,5

Fibrofolliculomas and trichodiscomas are well known for their association with Birt-Hogg-Dubé (BHD) syndrome when they present concomitantly and typically arise earlier in the third decade of life than solitary fibrofolliculomas; however, there have been reports of solitary fibrofolliculomas in patients aged 1 to 36 years.^4,6 The triad of BHD syndrome consists of multiple fibrofolliculomas, trichodiscomas, and acrochordons, and it is acquired in an autosomal-dominant manner, unlike solitary fibrofolliculomas, which typically are not inherited. Birt-Hogg-Dubé syndrome is caused by a mutation in the FLCN gene that codes for the tumor-suppressor protein folliculin, which when mutated can cause unregulated proliferation of cells.⁷ Solitary fibrofolliculomas and the multiple fibrofolliculomas seen in BHD syndrome are histologically similar.

Fibrofolliculoma can be clinically indistinguishable from fibroepithelioma of Pinkus, perifollicular fibroma, trichilemmoma, trichodiscoma, trichoepithelioma, and trichofolliculoma. All typically present clinically as flesh-colored papules,¹ although histologic distinction can be made (Table).^5,8-13

Fibrofolliculoma is a benign hamartoma that arises from the pilosebaceous follicle and consists of an expansion of the fibrous root sheath, which typically surrounds the hair follicle along with proliferating bands or ribbons of perifollicular connective tissue. As such, the hair follicle may be dilated and filled with keratin in the expanded infundibulum.⁸ Follicles also may be surrounded by a myxoid stroma.² In contrast, trichodiscoma is characterized by connective tissue with mature sebaceous lobules in the periphery. It has a myxoid stroma, as opposed to the more fibrous stroma seen in fibrofolliculomas.

Ackerman et al¹ considered both fibrofolliculomas and trichodiscomas to be hamartomas of the epithelial hair follicle. The exact etiology of each of these hamartomas is unknown, but the undifferentiated epithelial strands protruding from the hair follicle in a fibrofolliculoma lie in close proximity to sebaceous glands. Furthermore, the authors postulated that fibrofolliculomas and trichodiscomas constitute a spectrum that encompasses the differentiation process of a mantleoma, with fibrofolliculoma representing the beginning of mantleoma differentiation and trichodiscoma representing the end. This end stage of follicular differentiation is one in which there is a predominant stroma and the previously undifferentiated epithelium has formed into sebaceous ducts and lobules in the stroma.¹

Most cases of fibrofolliculoma and/or trichodiscoma arise in areas of dense sebaceous follicle concentration (eg, face), further supporting the hypothesis that sebaceous gland proliferation contributes to fibrofolliculoma.¹⁴ The case described here, with the fibrofolliculoma arising on the abdomen in conjunction with a trichodiscoma, is therefore worth noting because its location differs from what has been observed in previously reported cases.⁴

There are both surgical and medical options for treatment of fibrofolliculoma. Although surgical excision is an option for a single lesion, patients with multiple fibrofolliculomas or BHD may prefer removal with the combined CO₂ laser and erbium-doped YAG laser.¹⁵

Conclusion

We present a rare case of concomitant fibrofolliculoma and trichodiscoma arising on the unusual location of the abdomen. This report highlights the histopathologic features of multiple adnexal tumors and emphasizes the importance of biopsy for differentiating fibrofolliculoma and trichodiscoma.

Fibrofolliculomas and trichodiscomas typically present on the head or neck as smooth, flesh-colored, dome-shaped papules. These two entities are considered to constitute two separate time points on a spectrum of histopathologic changes in mantleoma differentiation.¹ Histologically, both are benign hamartomas of the pilosebaceous subunit and collectively are known as mantleomas. We present an unusual case of a concomitant fibrofolliculoma and trichodiscoma on the abdomen.

Case Report

An asymptomatic 54-year-old man presented for a routine full-body skin examination. A solitary, 2×1-cm, subcutaneous, doughy, mobile nodule was found on the left side of the abdomen with an overlying 2-mm yellow fleshy papule. The patient declined excision of the lesion, and it was recommended that he return for follow-up 3 months later.

The patient did not present for follow-up until 4.5 years later, at which point the lesion had grown to 3.0×2.5 cm in size. An excision was performed, at which time the lesion was noted to be cystic, extruding an oily, yellow-white liquid. Bacterial culture was negative. Histopathologic sections showed a dome-shaped papule with connection to the overlying epidermis. Epithelial extensions from the infundibular epithelium formed a fenestrated pattern surrounding a fibrous and mucinous stroma (Figure, A and B). The differential diagnosis at this time included an epidermal inclusion cyst, fibroma, intradermal nevus, verruca, hemangioma, angiofibroma, and lipoma.^2-4

The same lesion cut in a different plane of sectioning showed an expansile dermal nodule comprising clusters of sebaceous lobules surrounding a fibrous and mucinous stroma. Within the second lesion, fibrous and stromal components predominated over epithelial components (Figure, C). A diagnosis of fibrofolliculoma showing features of a trichodiscoma arising in the unusual location of the abdomen was made.

Comment

Solitary fibrofolliculomas and trichodiscomas are flesh-colored, dome-shaped papules that generally present on the face, specifically on the chin, nose, cheeks, ears, and eyebrows without considerable symptoms.^2,4,5 Clinically, fibrofolliculomas are indistinguishable from trichodiscomas but demonstrate different features on biopsy.^1,5

Fibrofolliculomas and trichodiscomas are well known for their association with Birt-Hogg-Dubé (BHD) syndrome when they present concomitantly and typically arise earlier in the third decade of life than solitary fibrofolliculomas; however, there have been reports of solitary fibrofolliculomas in patients aged 1 to 36 years.^4,6 The triad of BHD syndrome consists of multiple fibrofolliculomas, trichodiscomas, and acrochordons, and it is acquired in an autosomal-dominant manner, unlike solitary fibrofolliculomas, which typically are not inherited. Birt-Hogg-Dubé syndrome is caused by a mutation in the FLCN gene that codes for the tumor-suppressor protein folliculin, which when mutated can cause unregulated proliferation of cells.⁷ Solitary fibrofolliculomas and the multiple fibrofolliculomas seen in BHD syndrome are histologically similar.

Fibrofolliculoma can be clinically indistinguishable from fibroepithelioma of Pinkus, perifollicular fibroma, trichilemmoma, trichodiscoma, trichoepithelioma, and trichofolliculoma. All typically present clinically as flesh-colored papules,¹ although histologic distinction can be made (Table).^5,8-13

Fibrofolliculoma is a benign hamartoma that arises from the pilosebaceous follicle and consists of an expansion of the fibrous root sheath, which typically surrounds the hair follicle along with proliferating bands or ribbons of perifollicular connective tissue. As such, the hair follicle may be dilated and filled with keratin in the expanded infundibulum.⁸ Follicles also may be surrounded by a myxoid stroma.² In contrast, trichodiscoma is characterized by connective tissue with mature sebaceous lobules in the periphery. It has a myxoid stroma, as opposed to the more fibrous stroma seen in fibrofolliculomas.

Ackerman et al¹ considered both fibrofolliculomas and trichodiscomas to be hamartomas of the epithelial hair follicle. The exact etiology of each of these hamartomas is unknown, but the undifferentiated epithelial strands protruding from the hair follicle in a fibrofolliculoma lie in close proximity to sebaceous glands. Furthermore, the authors postulated that fibrofolliculomas and trichodiscomas constitute a spectrum that encompasses the differentiation process of a mantleoma, with fibrofolliculoma representing the beginning of mantleoma differentiation and trichodiscoma representing the end. This end stage of follicular differentiation is one in which there is a predominant stroma and the previously undifferentiated epithelium has formed into sebaceous ducts and lobules in the stroma.¹

Most cases of fibrofolliculoma and/or trichodiscoma arise in areas of dense sebaceous follicle concentration (eg, face), further supporting the hypothesis that sebaceous gland proliferation contributes to fibrofolliculoma.¹⁴ The case described here, with the fibrofolliculoma arising on the abdomen in conjunction with a trichodiscoma, is therefore worth noting because its location differs from what has been observed in previously reported cases.⁴

There are both surgical and medical options for treatment of fibrofolliculoma. Although surgical excision is an option for a single lesion, patients with multiple fibrofolliculomas or BHD may prefer removal with the combined CO₂ laser and erbium-doped YAG laser.¹⁵

Conclusion

We present a rare case of concomitant fibrofolliculoma and trichodiscoma arising on the unusual location of the abdomen. This report highlights the histopathologic features of multiple adnexal tumors and emphasizes the importance of biopsy for differentiating fibrofolliculoma and trichodiscoma.

Fibrofolliculomas and trichodiscomas typically present on the head or neck as smooth, flesh-colored, dome-shaped papules. These two entities are considered to constitute two separate time points on a spectrum of histopathologic changes in mantleoma differentiation.¹ Histologically, both are benign hamartomas of the pilosebaceous subunit and collectively are known as mantleomas. We present an unusual case of a concomitant fibrofolliculoma and trichodiscoma on the abdomen.

Case Report

An asymptomatic 54-year-old man presented for a routine full-body skin examination. A solitary, 2×1-cm, subcutaneous, doughy, mobile nodule was found on the left side of the abdomen with an overlying 2-mm yellow fleshy papule. The patient declined excision of the lesion, and it was recommended that he return for follow-up 3 months later.

The patient did not present for follow-up until 4.5 years later, at which point the lesion had grown to 3.0×2.5 cm in size. An excision was performed, at which time the lesion was noted to be cystic, extruding an oily, yellow-white liquid. Bacterial culture was negative. Histopathologic sections showed a dome-shaped papule with connection to the overlying epidermis. Epithelial extensions from the infundibular epithelium formed a fenestrated pattern surrounding a fibrous and mucinous stroma (Figure, A and B). The differential diagnosis at this time included an epidermal inclusion cyst, fibroma, intradermal nevus, verruca, hemangioma, angiofibroma, and lipoma.^2-4

The same lesion cut in a different plane of sectioning showed an expansile dermal nodule comprising clusters of sebaceous lobules surrounding a fibrous and mucinous stroma. Within the second lesion, fibrous and stromal components predominated over epithelial components (Figure, C). A diagnosis of fibrofolliculoma showing features of a trichodiscoma arising in the unusual location of the abdomen was made.

Comment

Solitary fibrofolliculomas and trichodiscomas are flesh-colored, dome-shaped papules that generally present on the face, specifically on the chin, nose, cheeks, ears, and eyebrows without considerable symptoms.^2,4,5 Clinically, fibrofolliculomas are indistinguishable from trichodiscomas but demonstrate different features on biopsy.^1,5

Fibrofolliculomas and trichodiscomas are well known for their association with Birt-Hogg-Dubé (BHD) syndrome when they present concomitantly and typically arise earlier in the third decade of life than solitary fibrofolliculomas; however, there have been reports of solitary fibrofolliculomas in patients aged 1 to 36 years.^4,6 The triad of BHD syndrome consists of multiple fibrofolliculomas, trichodiscomas, and acrochordons, and it is acquired in an autosomal-dominant manner, unlike solitary fibrofolliculomas, which typically are not inherited. Birt-Hogg-Dubé syndrome is caused by a mutation in the FLCN gene that codes for the tumor-suppressor protein folliculin, which when mutated can cause unregulated proliferation of cells.⁷ Solitary fibrofolliculomas and the multiple fibrofolliculomas seen in BHD syndrome are histologically similar.

Fibrofolliculoma can be clinically indistinguishable from fibroepithelioma of Pinkus, perifollicular fibroma, trichilemmoma, trichodiscoma, trichoepithelioma, and trichofolliculoma. All typically present clinically as flesh-colored papules,¹ although histologic distinction can be made (Table).^5,8-13

Fibrofolliculoma is a benign hamartoma that arises from the pilosebaceous follicle and consists of an expansion of the fibrous root sheath, which typically surrounds the hair follicle along with proliferating bands or ribbons of perifollicular connective tissue. As such, the hair follicle may be dilated and filled with keratin in the expanded infundibulum.⁸ Follicles also may be surrounded by a myxoid stroma.² In contrast, trichodiscoma is characterized by connective tissue with mature sebaceous lobules in the periphery. It has a myxoid stroma, as opposed to the more fibrous stroma seen in fibrofolliculomas.

Ackerman et al¹ considered both fibrofolliculomas and trichodiscomas to be hamartomas of the epithelial hair follicle. The exact etiology of each of these hamartomas is unknown, but the undifferentiated epithelial strands protruding from the hair follicle in a fibrofolliculoma lie in close proximity to sebaceous glands. Furthermore, the authors postulated that fibrofolliculomas and trichodiscomas constitute a spectrum that encompasses the differentiation process of a mantleoma, with fibrofolliculoma representing the beginning of mantleoma differentiation and trichodiscoma representing the end. This end stage of follicular differentiation is one in which there is a predominant stroma and the previously undifferentiated epithelium has formed into sebaceous ducts and lobules in the stroma.¹

Most cases of fibrofolliculoma and/or trichodiscoma arise in areas of dense sebaceous follicle concentration (eg, face), further supporting the hypothesis that sebaceous gland proliferation contributes to fibrofolliculoma.¹⁴ The case described here, with the fibrofolliculoma arising on the abdomen in conjunction with a trichodiscoma, is therefore worth noting because its location differs from what has been observed in previously reported cases.⁴

There are both surgical and medical options for treatment of fibrofolliculoma. Although surgical excision is an option for a single lesion, patients with multiple fibrofolliculomas or BHD may prefer removal with the combined CO₂ laser and erbium-doped YAG laser.¹⁵

Conclusion

We present a rare case of concomitant fibrofolliculoma and trichodiscoma arising on the unusual location of the abdomen. This report highlights the histopathologic features of multiple adnexal tumors and emphasizes the importance of biopsy for differentiating fibrofolliculoma and trichodiscoma.