Multiple Onychomatricomas as a Rare Clinical Presentation with BAP1 Mutation: A Case Report

Onychomatricoma (OM) is a rare benign fibroepithelial tumor of the nail that originates from the nail matrix and the nail bed. It presents as a solitary lesion and leads to thickening of the nail plate, yellowish longitudinal bands, leuko-xanthonchia, transverse overcurvature, and splinter hemorrhages.

We report a 50-year-old woman with complaint of some changes in the shape and color of her thumbnails. On her dermatologic examination, leuko-xanthonchia extending from the distal nail to the lunula, irregularity on the lunula, and erythematous and whitish bands on the lunula were found on her left and right thumbnail. Both lesions were treated surgically. The histopathological evaluation of both lesions was consistent with OM. The BAP1 gene was reported as likely pathogenic.

OM commonly affects a single nail. The involvement of multiple nails should not be considered a reason to exclude the diagnosis of OM. Multi-nail dystrophies should be considered in case of presence of multiple lesions. In cases with multiple OM, evaluation for a BAP1 mutation should be considered.