Apocrine poroma with sebaceous differentiation

Poromas have been classified as eccrine neoplasms, but several recent repor ts of poroid tumors with sebaceous, follicular, and apocrine differentiatio n have challenged this concept. We report a case of apocrine poroma with se baceous differentiation. A 69-year-old man presented with an asymptomatic e levated erythematous plaque. Histopathology revealed cellular nests compose d 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 folliculoseb aceous and apocrine units, we believe that this lesion represents an apocri ne poroma with sebaceous differentiation.