Sweat gland carcinoma of the hand: two cases of malignant eccrine spiradenoma.

Two cases of malignant eccrine spiradenoma of the hand are reported. This malignancy is potentially fatal and is believed to arise from preexisting, long-standing benign spiradenomas. These rare tumors should be considered in the hand surgeon's evaluation and management of any long-standing undiagnosed tumor of the hand. Benign spiradenomas should be excised completely and the patient followed carefully. Location and grade of established malignant tumors should dictate therapy.