Secretory carcinoma of the skin: Case report and review of the literature

M ammary analogue secretory carcinoma is a primary salivary gland tumor that was first described in 2010, with histologic, immunophenotypic, and genetic features reminiscent of secretory carcinoma of the breast. Both tumors harbor the same defining ETV6eNTRK3 fusion gene, resulting from the t(12;15) (p13;q25) translocation. Of interest to dermatopathologists, primary cutaneous tumors resembling secretory carcinoma of salivary gland and breast have been recently described in several case reports and a case series. Such cases likely arise from skin adnexa, given the absence of adjacent ectopic breast or salivary tissue, along with subsequent exclusion of extracutaneous involvement. Unlike their salivary gland and breast counterparts, secretory carcinoma originating from skin adnexa have demonstrated inconsistent positivity for the ETV6 gene rearrangement. We describe the first reported case of secretory carcinoma involving the cutaneous surface of the upper lip, harboring the classic genetic signature of its salivary gland and breast secretory carcinoma counterparts.