Acantholytic Dyskeratotic Acanthoma of the Nail Revealed by a Longitudinal Erythronychia

Focal acantholytic dyskeratosis is a distinctive histological pattern first described by Ackerman in 1972, consisting of focal suprabasal clefts in the epidermis and dyskeratotic cells at all levels of the epidermis with hyperkeratosis and parakeratosis. The first case of subungual acantholytic dyskeratosis acanthoma (ADA) was reported in 1990. This subungual variant is a very rare entity.

A 63-year-old female patient consulted for a longitudinal erythronychia (LE) associated with distal onycholysis. Dermoscopy showed LE with a few splinter hemorrhages, with localized hyperkeratosis and thinning of the nail plate at the free edge. Histopathology confirmed the diagnosis of ADA.

ADA is a rare tumor that could mimic various inflammatory or neoplastic conditions. To our knowledge, this is the eighth reported case in the literature. This uncommon entity could mimic various inflammatory or neoplastic conditions.