Eccrine porocarcinoma, a malignancy of the eccrine sweat glands, is extremely rare. Our report and a review of the literature (70 cases) emphasize the features of this tumor. Age at time of treatment ranged from 19 to 94 years (mean 67 years). Duration of the lesion ranged from two months to 50 years; 31 (44%) had the lesion present > or = 5 years. Forty-four patients (62%) had tumors located on the extremities, 13 (19%) on the head and neck region and 12 (17%) on the trunk. All patients whose race is known were white. Primary treatment should consist of wide local excision and regional lymphadenectomy, if clinically indicated. Although there is a significant risk of cutaneous, regional lymph node, or visceral metastases, the value of elective or therapeutic regional lymphadenectomy is unknown, as is the role of adjunctive therapy.