Acquired Digital Fibrokeratoma
Acquired digital fibrokeratoma (aka acral fibrokeratoma) is a slow-growing benign lesion that is usually seen in adults (M>F).The etiology is not known but some consider it a response to trauma or subclinical injury. Clinically, it resembles a cutaneous horn or rudimentary supernumerary digits. The usual sites of involvement are fingers, proximal hand, toes, and even soles. A similar lesion has been reported in subungual or periungual region of patients with tuberous sclerosis. They are called periungual fibrokeratomas (aka Koenen tumors). Microscopically, this pedunculated lesion shows marked acanthosis and hyperkeratosis. The center consists of dense collagen, mature fibroblasts, elastic fibers, and blood vessels. There is paucity of nerve fibers and tactile (Pacinian) corpuscles allowing its distinction from accessory digits. Simple excision is curative. Case History: Adult male who presented with 0.9 cm dome shaped painless nodule on the dorsal aspect of his left index finger. There was no history of trauma. The excised lesion showed microscopic features of fibrokeratoma. Case courtesy of: Dr. Sanjay D. Deshmukh (Professor of Pathology) & Dr. Vishal A. Indurkar (Associate Professor of Dermatology), Dr. Vithalrao Vikhe Patil Medical College and Hospital, Ahmednagar, India.