A case of focal acantholytic dyskeratosis presenting as a solitary papule

Focal acantholytic dyskeratosis (FAD) was introduced by Ackerman to describe a group of clinically various dermatologic conditions having a similar histologic appearance. The characteristic histologic findings included (1) suprabasilar clefts around preserved papillae, (2) acantholytic and dyskeratotic cells at all levels of the epidermis, and (3) hyperkeratosis and parakeratosis. Almost solitary lesions of FAD are histologically incidental or clinically nodular(warty dyskeratoma). The papular form of solitary FAD is an extremely rare condition identified by the reviewing of specimens or reported as a solitary lesion developing in the mouth. We report a case of focal acantholytic dyskeratosis presenting as a solitary papule on the perianal area.