Expression of differentiation antigens in benign sweat gland tumours.

Fifty benign sweat gland tumours were studied for the expression of carcinoembryonic antigen (CEA) and apocrine epithelial antigen (AEA), using immunohistochemical methods. CEA was found in thirty-two and AEA in thirty-three neoplasms. Both antigens were located in the epithelium of the luminal structures and in the intraluminar material and CEA was occasionally found also in proliferating cells. Co-expression of CEA and AEA occurred frequently in cases of syringoma, syringocystadenoma papilliferum, hidradenoma papilliferum, eccrine spiradenoma and clear cell hidradenoma. AEA was seen also in tumours showing eccrine differentiation, even though it is not present in normal eccrine sweat ducts.