BACKGROUND: Eccrine porocarcinoma is an uncommon neoplasm of the intraepidermal sweat gland duct. METHODS: A case of porocarcinoma of the right heel in a male age 51 years is described with a review of pertinent literature. The surgically excised neoplasm was evaluated by routine histology and transmission electron microscopy. RESULTS: The porocarcinoma showed extensive nuclear pleomorphisms with frequent, multinucleated tumor giant cells, focal epidermotrophic spread within the epidermis, a peripheral, eccrine syringofibroadenoma-like growth pattern, and an origin in a contiguous eccrine poroma. Ultrastructurally, the squamous 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 within the epidermis and its origin in a contiguous eccrine poroma supported the diagnosis of porocarcinoma. The eccrine syringofibroadenoma-like growth pattern in the periphery of the tumor was a unique and previously undescribed feature of the porocarcinoma. The presence of intracytoplasmic lumens in squamous tumor cells mimicked embryonic development of the intraepidermal sweat gland duct.
BACKGROUND: Eccrine porocarcinoma is an uncommon neoplasm of the intraepidermal sweat gland duct. METHODS: A case of porocarcinoma of the right heel in a male age 51 years is described with a review of pertinent literature. The surgically excised neoplasm was evaluated by routine histology and transmission electron microscopy. RESULTS: The porocarcinoma showed extensive nuclear pleomorphisms with frequent, multinucleated tumor giant cells, focal epidermotrophic spread within the epidermis, a peripheral, eccrine syringofibroadenoma-like growth pattern, and an origin in a contiguous eccrine poroma. Ultrastructurally, the squamous 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 within the epidermis and its origin in a contiguous eccrine poroma supported the diagnosis of porocarcinoma. The eccrine syringofibroadenoma-like growth pattern in the periphery of the tumor was a unique and previously undescribed feature of the porocarcinoma. The presence of intracytoplasmic lumens in squamous tumor cells mimicked embryonic development of the intraepidermal sweat gland duct.