Role of Radiotherapy in Aggressive Digital Papillary Adenocarcinoma.

Aggressive digital papillary adenocarcinoma (ADPA) is a rare and often misdiagnosed malignant tumor of the sweat glands, most commonly encountered on the extremities. Due to the relatively high metastatic potential of the tumor, aggressive surgical treatment, including amputation, is generally recommended. We present a case of a 36-year-old male with an over 10-year history of a skin lesion on the right hand in the web space between the index and the middle finger. Histologically, the lesion revealed a malignant epithelioid neoplasm with features consistent with ADPA. The lesion was treated with 5-weeks preoperative radiation (total 5000 cGy) followed by surgical resection. There was no evidence of residual disease confirmed by pathological study of re-excision specimen as well as imaging studies. This is, to the best of knowledge, the first report of complete regression of an ADPA after radiotherapy.