Digital Papillary Adenocarcinoma in the Dorsal Proximal Ring Finger.

Digital papillary adenocarcinoma (DPA) is a rare and aggressive tumor arising from the eccrine sweat glands. It is found on the hands and feet and most commonly occurs on the volar and distal finger tips. In this report, we describe a DPA in a 45-year-old woman who presented with a slowly enlarging mass on the dorsal aspect of her proximal ring finger. This report shows that DPA may clinically present as a relatively benign-appearing mass and in an atypical location. Surgical excision, followed by histologic and immunohistochemical evaluations of even benign-appearing digital masses, is important because this is the only way a DPA can be diagnosed.