Acquired periungual fibrokeratoma: a case report.

Acquired periungual fibrokeratoma (APF) is an uncommon lesion located around the nail and related to acquired digital fibrokeratoma. Histologic features of APF include a core of thick collagen bundles oriented along the longitudinal axis of the tumor and a very characteristic pseudo-nail plate formation. Different terms have been used to describe these lesions, and there has been no consensus on the terminology for some years. It is now believed that trauma may play a role in the pathogenesis of these periungual lesions.