Search

Background Sebaceous tumors are adnexal neoplasms showing sebocytic differentiation. They range from benign to malignant and are associated with Muir-Torre syndrome (MTS). Several clinical and histopathological features associated with MTS have been described. Sebaceous tumors with an overlying cutaneous horn are extremely rare. Methods Hematoxylin and eosin-stained slides were retrospectively reviewed to identify sebaceous tumors with marked hyperkeratosis, a condition that is often associated with cutaneous horns. Clinical correlation and mismatch repair protein immunohistochemical studies were then conducted. Results Four tumors from three patients were identified in our archive. Three were classified as sebaceous adenomas, and the fourth was considered as a borderline sebaceous tumor favoring well-differentiated sebaceous carcinoma. All cases showed loss of expression of mismatch repair proteins (three tumors from two patients exhibited lost expression of MSH2 and MSH6, and the fourth exhibited lost expression of MLH1 and PMS2). Additionally, one patient presented characteristic clinical manifestations of MTS, including multiple sebaceous adenomas and visceral carcinomas. Conclusions We suggest that extraocular well-differentiated sebaceous neoplasms with overlying cutaneous horns may be an indication of underlying mismatch repair protein deficiency and potential MTS. This distinctive morphology might be an exaggerated combination of other features associated with MTS, i.e. keratoacanthoma-like architecture and extensive holocrine secretion.

Background Melanoma is a heterogeneous group of diseases with distinct sets of genetic changes. Recurrent and mutually exclusive C>T or CC>TT transition mutations were identified in the promoter region of the reverse transcriptase catalytic subunit of the telomerase gene (TERT) in melanoma recently, and it was suggested that they enhanced the expression of TERT gene and played important roles in the melanoma pathogenesis. These mono or di-nucleotide transitions were ultraviolet (UV)-signature mutations. Methods In this study, polymerase chain reaction and direct sequencing of TERT promoter using formalin-fixed and paraffin-embedded tissue was performed to investigate whether these UV-signature mutations were also present in acral lentiginous melanoma. Results TERT promoter mutation was identified in only 2 of the 32 cases (6%) of acral lentiginous melanomas while it was identified in 3 of the 9 cases (33%) of non-acral cutaneous melanomas. The difference was statistically significant (p = 0.028). Conclusions The rarity of TERT promoter mutation in the acral lentiginous melanoma was consistent with the supposed role of UV light in the melanoma pathogenesis and also corroborated the view that acral lentiginous melanomas have a different pathogenesis with the melanomas from sun-exposed sites.

Melanoma is a heterogeneous group of diseases with distinct sets of genetic changes. Recurrent and mutually exclusive CT or CCTT transition mutations were identified in the promoter region of the reverse transcriptase catalytic subunit of the telomerase gene (TERT) in melanoma recently, and it was suggested that they enhanced the expression of TERT gene and played important roles in the melanoma pathogenesis. These mono or di-nucleotide transitions were ultraviolet (UV)-signature mutations.In this study, polymerase chain reaction and direct sequencing of TERT promoter using formalin-fixed and paraffin-embedded tissue was performed to investigate whether these UV-signature mutations were also present in acral lentiginous melanoma.TERT promoter mutation was identified in only 2 of the 32 cases (6%) of acral lentiginous melanomas while it was identified in 3 of the 9 cases (33%) of non-acral cutaneous melanomas. The difference was statistically significant (p = 0.028).The rarity of TERT promoter mutation in the acral lentiginous melanoma was consistent with the supposed role of UV light in the melanoma pathogenesis and also corroborated the view that acral lentiginous melanomas have a different pathogenesis with the melanomas from sun-exposed sites.

Sebaceous tumors are adnexal neoplasms showing sebocytic differentiation. They range from benign to malignant and are associated with Muir-Torre syndrome (MTS). Several clinical and histopathological features associated with MTS have been described. Sebaceous tumors with an overlying cutaneous horn are extremely rare.Hematoxylin and eosin-stained slides were retrospectively reviewed to identify sebaceous tumors with marked hyperkeratosis, a condition that is often associated with cutaneous horns. Clinical correlation and mismatch repair protein immunohistochemical studies were then conducted.Four tumors from three patients were identified in our archive. Three were classified as sebaceous adenomas, and the fourth was considered as a borderline sebaceous tumor favoring well-differentiated sebaceous carcinoma. All cases showed loss of expression of mismatch repair proteins (three tumors from two patients exhibited lost expression of MSH2 and MSH6, and the fourth exhibited lost expression of MLH1 and PMS2). Additionally, one patient presented characteristic clinical manifestations of MTS, including multiple sebaceous adenomas and visceral carcinomas.We suggest that extraocular well-differentiated sebaceous neoplasms with overlying cutaneous horns may be an indication of underlying mismatch repair protein deficiency and potential MTS. This distinctive morphology might be an exaggerated combination of other features associated with MTS, i.e. keratoacanthoma-like architecture and extensive holocrine secretion.