Dermoscopic Features of Onychomatricoma: A Study of 34 Cases.

BACKGROUND: Onychomatricoma is a benign tumor of the nail matrix with a precise histopathological definition but many different clinical features and differential diagnoses.

OBJECTIVES: The diagnosis of onychomatricoma is based on the pathological examination of a surgical specimen. The objective of this study was to define preoperative diagnostic criteria using noninvasive investigations: observation and dermoscopy.

METHODS: A total of 34 cases of onychomatricoma were studied. In detail, 6 observers evaluated 12 clinical and 12 dermoscopical criteria as present or absent.

RESULTS: For clinical criteria, the highest mean values were leuconychia (3.21), splinter hemorrhages (3.45), and thickening of the plate (3.0). Dermoscopical criteria were more often found present, such as longitudinal parallel white lines (4.33), parallel lesion edges (4.61), splinter hemorrhages (4.48), dark dots (3.96), free-edge nail pitting (4.5), and thickening of the free edge (5.27).

CONCLUSION: Dermoscopical criteria for onychomatricoma are more frequently present and less subject to divergent interpretation. This offers new and original preoperative reliable diagnostic criteria and should be used in the evaluation of nail tumors.