Abstract

We reported a case of microcystic adnexal carcinoma occuring on the right upper lip of a 51-year-old man. Microscopically, small solid nests and strands of tumor were distributed throughout the whole dermis with infiltration into subcutaneous tissue. In the upper dermis, there were small cysts of varying size. In the middle dermis, there were small ductal structures or tadpole-shaped epithelial islands.
Immunohistochemically, CEA was focally positive some ductal structures. S-100 protein stain was negative. 34β E12 was positive in all three components of the tumors. 34 β H11 was moderately positive in some cysts and ductal structures. CA19-9 and EMA were positive in most cysts and ductal structures.
These observations confirm that this tumor appeared at least capable of eccrine sweat gland differentiation.