Malignant melanoma without metastasis in a giant nevus.

A case of giant hairy nevus is presented in which prominent experts on diagnosis of this type of lesion were consulted. About half were of the opinion that it had degenerated into a malignant melanoma, but nevertheless the patient is alive and relatively well sixteen years after this diagnosis. This is one more case that attests to the fact that a tumor can appear very malignant histologically but, for reasons still unclear, neither metastasize nor lead to the rapid demise of the patient.