A woman in her late 80s presented with a 5-month history of a new 2.8-cm blue-black nodule on her left lateral upper back (Figure, A). She reported that the lesion was mildly pruritic. The results of the physical examination were unremarkable and revealed no lymphadenopathy. A full review of systems was notable for unintentional weight loss, loss of appetite, diarrhea, and hair loss. Her history was significant for extensive sun damage, multiple nonmelanoma skin cancers, and a nonulcerated superficial spreading malignant melanoma (Breslow thickness, 0.56 mm) involving the right dorsal forearm in 2001. This lesion was reexcised, and histologic analysis showed no residual melanoma.