In 1987 a clinicopathologic study by the Armed Forces Institute of Pathology (AFIP) of rare sweat gland tumors, termed aggressive digital papillary adenoma and adenocarcinoma, was published. Since that time, the AFIP has continued to collect these tumors for study. Based on additional follow-up data, we think the original classification of these tumors requires revision. Sixty-seven cases of aggressive digital papillary adenoma and adenocarcinoma were studied according to their clinical characteristics and histologic features. Fifty of these were originally diagnosed as adenoma and 17 as adenocarcinoma. Follow up on 45 (67%) of the patients was obtained. None of the clinical or histologic parameters studied were found to be predictive of recurrence or metastasis, indicating that the originally proposed criteria for distinguishing between benign (adenoma) and malignant (adenocarcinoma) do not predict biologic behavior. When primary tumors were treated by subsequent reexcision or amputation, only one recurred (5%), when not so treated, 11 recurred (50%) regardless of the original diagnosis (p <0.05). Metastasis occurred in six (14%) cases and in three cases led to the death of the patient. Three of these metastatic cases had met the earlier criteria for adenoma. Pulmonary metastases were observed in five cases. No effective treatment for widespread metastatic disease has yet been developed. Because histologic features with prognostic significance could not be demonstrated in this retrospective review, we propose that all aggressive digital papillary tumors be designated aggressive digital papillary adenocarcinoma.