POROCARCINOMA OF THE HEEL - A CASE-REPORT WITH UNUSUAL HISTOLOGIC FEATURES

BACKGROUND. Eccrine porocarcinoma is an uncommon neoplasm of the intra epidermal sweat gland duct. METHODS. A case of porocarcinoma of the ri ght heel in a male age 51 years is described with a review of pertinen t literature. The surgically excised neoplasm was evaluated by routine histology and transmission electron microscopy. RESULTS. The porocarc inoma showed extensive nuclear pleomorphisms with frequent, multinucle ated tumor giant cells, focal epidermotrophic spread within the epider mis, a peripheral, eccrine syingofibroadenoma-like growth pattern, and an origin in a contiguous eccrine poroma. Ultrastructurally, the squa mous tumor cells contained rare intracytoplasmic lumens. CONCLUSIONS. The extensive nuclear pleomorphism with frequent tumor giant cells was an unusual feature of the porocarcinoma. Its epidermotrophic spread w ithin the epidermis and its origin in a contiguous eccrine poroma supp orted the diagnosis of porocarcinoma. The eccrine syringofibroadenoma- like growth pattern in the periphery of the tumor was a unique and pre viously undescribed feature of the porocarcinoma. The presence of intr acytoplasmic lumens in squamous tumor cells mimicked embryonic develop ment of the intraepidermal sweat gland duct. (C) 1996 American Cancer Society.