PORAL NEOPLASM WITH COMBINED SEBACEOUS AND APOCRINE DIFFERENTIATION

Poromas have been considered the hallmark of benign eccrine neoplasms. The literature describes six cases of poroma differentiating toward a pocrine and sebaceous lineage. We present a benign poroid neoplasm tha t has the silhouette of hidroacanthoma simplex and also shows sebaceou s and apocrine components, The sebaceous attributes include sebocytes, in various stages of maturation, and sebaceous ductal structures. The apocrine component consists of tubules lined by a single or double la yer of cuboidal cells that exhibit decapitation secretion. Although pr esent-day techniques cannot unequivocally distinguish apocrine from ec crine differentiation, we think that the poroma-like portion of this n eoplasm is most likely apocrine, based on the common embryologic origi n of sebaceous, apocrine, and hair follicle structures. We suggest des ignating these types of tumors as ''poral neoplasm'' and specifying th e type of differentiation: eccrine poral neoplasm, for those that lack follicular and/or sebaceous differentiation, and apocrine poral neopl asm. for those with sebaceous and/or follicular differentiation.