Onychomatricoma in Patients with Dark Phototype: Epidemiological, Clinical, and Dermoscopic Findings in 24 Cases.

Introduction: Onychomatricoma is a benign tumor that originates from the nail matrix. The main clinical features reported include longitudinal thickening of the nail plate, splinter hemorrhages, and xanthonychia.

Objective: The aims of the study were to describe epidemiological, clinical, and dermoscopy data of patients with dark skin phototypes (Fitzpatrick IV, V, VI) diagnosed with onychomatricoma and to compare the findings with previously reported cases.

Methods: The medical records of 24 patients with dark skin phototype, and a diagnosis of onychomatricoma, collected from 2015 to 2023, were reviewed and analyzed.

Results: Thirteen tumors (54.17%) occurred in the fingers and eleven tumors (45.83%) in the toenails. The main clinical and dermoscopic features found were increased nail thickness (21 cases; 88%), xanthonychia (20 cases; 83%), longitudinal melanonychia (18 cases; 75%), transverse hypercurvature of the nail plate (18 cases; 75%), and free edge cavitations (18 cases; 75%).

Conclusion: The clinical and dermoscopic features of onychomatricoma in patients with dark phototypes are similar to those in fair phototypes, except for the higher prevalence of melanonychia (75% vs. 24.2%).