Eccrine syringofibroadenoma (Mascaro): an immunohistochemical study

Eccrine syringofibroadenoma is an uncommon benign eccrine tumor, which was first described by Mascaro in 1963. It usually develops on the extremities of elderly persons. We report on a 74-year-old man who presented with a 2-year history of a slowly growing lesion on his face. A detailed histologic and immunohistochemical study was performed on the biopsy material. The tumor consisted of epidermal-derived anastomosing thin epithelial cords embedded in a fibrovascular stroma. The epithelial cords contained ductal and cystic structures lined by luminal cells, which were decorated by antibodies against carcinoembryonic antigen, keratin K19, K8, and K18. Antibody to keratin K6 decorated the luminal walls of the acrosyringia. Antibodies to filaggrin decorated the superficial luminal structures. These results suggest dual acrosyringial and dermal duct differentiation in syringofibroadenoma.