Onychomatricoma.

BACKGROUND: Onychomatricoma is a rare benign tumor originating in the nail matrix. Only eight cases have been reported until now.

OBJECTIVE: The clinical and histopathological features of this recently reported tumor will be described and its differential diagnoses outlined. A typical case of onychomatricoma is described in a 62-year-old white man.

RESULTS: Clinically, onychomatricoma is characterized by: 1) a yellowish discoloration of a longitudinal segment of the nail plate with small splinter hemorrhages within the proximal portion of the nail; 2) a thickening with increased transversal curvature of the involved nail plate positively corresponding with the yellow discoloration; and 3) a matrix tumor consisting of multiple fine filiform projections that extend into the thickened nail plate. The treatment of onychomatricoma is complete excision of the tumor.

CONCLUSION: Onychomatricoma is a new entity with clinical and histopathological features that are characteristic enough to make the correct diagnosis.