Nail matrix melanoma in situ: Conservative surgical management

Background: Nail unit melanoma (NUM) is a rare variant of acral lentiginous melanoma. The differential diagnosis is wide but an acquired brown streak in the nail of a fair-skinned person must be considered a potential melanoma. Dermatoscopy helps clinicians to more accurately decide if a nail apparatus biopsy is necessary. Methods: We report the case of a 61-year-old Caucasian woman with melanonychia occupying the central portion of the right thumbnail plate with 1 year of evolution. Dermatoscopy showed a brown pigmentation overlaid by longitudinal irregular lines. An excisional biopsy was performed, and pathological examination revealed melanoma in situ. For safety reasons, the nail unit was totally removed down to the phalangeal bone 3 weeks later, and a full-thickness skin graft taken from the arm was used for reconstruction. Conclusion: NUMs pose a difficult treatment challenge. Wide excision with phalanx amputation is not satisfactory for patients with in situ and early invasive melanoma. Full-thickness skin grafting after total nail unit excision is a simple procedure providing a good functional and cosmetic outcome.