Longitudinal melanonychia: detection and management of nail melanoma.

Malignant melanoma of the nail confers a higher mortality rate compared to other cutaneous melanomas, which is often attributable to delayed diagnosis. Two-thirds of nail melanomas present as longitudinal melanonychia (LM), longitudinally-oriented brown-black bands of pigment in the nail plate. This article delineates the appropriate clinical approach toward evaluation and management of a patient with longitudinal melanonychia, which includes determining risk factors for melanoma, recognizing scenarios in which biopsy is indicated, selecting the appropriate biopsy technique, and managing a patient in whom the diagnosis of nail melanoma has been made.