Spontaneous partial regression of primary melanoma with death due to metastases.

A 42-year-old man had a metastatic melanoma in the brain, but no obvious primary melanoma could be detected. A halo nevus-like depigmented lesion was found on the left side of the patient's back. The histopathologic features of the depigmented lesion were compatible with those of a spontaneously regressed primary lesion of malignant melanoma. Enhanced immune responses to autologous and homologous melanoma cells were not detected when investigated in the late disease stage. Subsequently, the patient died of disseminated melanoma.