[Adenoid cystic sweat gland carcinoma. A clinicopathologic and immunohistochemical study].

Adenoid cystic carcinoma of the skin is one of the rarest sweat gland tumours. We have studied two cases of adenoid cystic sweat gland carcinoma clinically, histologically and immunohistochemically. One tumour was located on the occiput of an 18-year-old male patient, while the other developed on the back of a 49-year-old woman. Histologically, both carcinomas were characterized by basaloid tumour cells showing the typical adenoid-cystic growth pattern. The cells were arranged in solid, cribriform, tubular and cystic aggregates, which were surrounded by mucoid, Alcian blue material. Immunohistochemically, the tumour cells showed coexpression of cytokeratins typical of stratified epithelia (CK1/5/10/14) and cytokeratins of the simple epithelial type, namely CK7, CK8, CK18, and CK19. Coexpression of these cytokeratins is usually observed in normal fetal sweat glands, but not in adult sweat glands.