This photo shows longitudinal pigmentation of the nail (melanonychia striata; blue arrow) and hyperpigmentation extending across the lunula to the proximal nail fold (Hutchinson sign; red arrow) of the middle finger. Acral-lentiginous melanoma, the most common type of melanoma among people with dark skin, occurs on palmar, plantar, or subungual skin. This patient was diagnosed with acral-lentiginous melanoma (a form of malignant melanoma). (The dark area on the thumbnail is a subungual hematoma.)