ABSTRACT
Onychomatricoma is a benign nail tumor that originates from the nail matrix. It mainly affects the fingernails and presents with a thickened nail plate (localized or full thickness), over-curvature (transverse and longitudinal), and a whitish/yellow coloration with splinter hemorrhages (xantholeukonychia). Pigmented tumors have been also described. The frontal view of the nail plate shows multiple holes in its thickened free margin (honeycomb holes) corresponding to the digitated fibroepithelial projections of the tumor that grow longitudinally within the nail plate. Onychomycosis is frequently associated, and this often delays the diagnosis. Dermatoscopy shows longitudinal parallel whitish lines, parallel lesion edges, splinter hemorrhages, tortuous hairpin vessels, dark dots, and thickening of the free edge. Observation of the distal margin of the nail plate shows the characteristic holes that make the diagnosis ( Figure 22.1 ).
