A case of metastatic malignant melanoma showing spontaneous complete regression of the primary lesion.

A 53-year-old female was admitted to our hospital for multiple brain tumors. One of them was surgically removed and its histological examination showed malignant melanoma. She had multiple lymph node metastasis on the right groin, a blue nevuslike macule on the right sole, and disseminated depigmented macules on the whole body. Although the brain tumors were treated by stereotactic radiosurgery, the patient died of meningeal involvement five month after the admission. The biopsy specimen of the plantar lesion showed no melanocyte in both epidermis and dermis, whereas a number of melanophages were seen in papillary dermis. Intraepidermal infiltration of lymphocytes was also detected. Dermal dendrocyte-like cells were recognized ultrastructually in papillary dermis mixed with melanophages. Those findings suggested that the plantar lesion might be the result of spontaneous complete regression of primary malignant melanoma. [Skin Cancer (Japan) 2001; 16: 179-183]