Eccrine sweat gland carcinoma: a case report and review of diagnosis and treatment.

Carcinomas of the skin appendices are rare neoplasms but for prognostic reasons it is important to differentiate them from the indolent squamous and basal cell carcinomas, as their behavior is more aggressive. We report on a case of eccrine sweat gland carcinoma that displayed all the typical features of those neoplasms. The patient sought medical attention after a lesion in his foot, already present for four years, began to enlarge and developed satellite lesions. The pathological diagnosis was made only after the lesion was initially misdiagnosed as basal cell carcinoma of the skin. Multiple chemotherapeutic regimens and radiation therapy were administered with only temporary benefit. The patient developed distant metastatic disease but survived with metastases for three years. He died nine years after the initial lesion developed in his foot and five years after the diagnosis. The diagnosis of sweat gland carcinomas can be facilitated by histochemical stains. In contrast to squamous and basal cell carcinomas of the skin, these are generally positive for the carcinoembryonic antigen (CEA). Once metastatic, these neoplasms are only infrequently, and usually briefly, responsive to either chemotherapy or radiotherapy and new treatments are urgently needed. Early recognition of the entity may allow more timely treatment.