Apocrine poroma with sebaceous differentiation

Abstract

Poromas have been classified as eccrine neoplasms, but several recent reports of poroid tumors with sebaceous, follicular, and apocrine differentiation have challenged this concept. We report a case of apocrine poroma with sebaceous differentiation. A 69-year-old man presented with an asymptomatic elevated erythematous plaque. Histopathology revealed cellular nests composed of cuboidal poroid cells and sebocytes. The nests varied in size and were entirely intraepidermally arranged in a growth pattern similar to that of hidroacanthoma simplex. Given the common embryologic origin of folliculosebaceous and apocrine units, we believe that this lesion represents an apocrine poroma with sebaceous differentiation.