[Subungual malignant lentigo with longitudinal nail pigmentation--diagnosis and surgical treatment]

A subungual Lentigo maligna was found to be the cause of a longitudinal melanotic stripe in the thumbnail of a 45-year old male. Because of the possibility of a malignant process, a histological diagnosis must be made in all cases of pigmented nail stripes. The best procedure is complete excision of the lesion in a bloodless field, followed immediately by frozen section analysis. According to the result either a larger operation is made during the same session or the wound closed. This procedure enables a specific therapy of pigmented subungual lesions, and contributes to the early recognition and prophylaxis of subungual malignant melanomas.