Long-term spontaneous regression of malignant melanoma with visceral metastases. Report of a case with immunologic profile.

A case of a 58-year-old woman with viscerally metastatic malignant melanoma is presented 12 years after spontaneous and complete regression of disease. Diagnosis of primary and metastatic lesions was confirmed by review of tissue sections. The presence and subsequent absence of visceral metastases were documented by open liver biopsies. Sections of metastatic lesions revealed extensive necrosis of tumor and infiltration of lymphocytes and plasma cells. Skin testing showed a strongly positive delayed hypersensitivity response to dinitrochlorobenzene (DNCB), to a standard battery of bacterial and fungal antigens, and to two of four preparations of allogeneic melanoma antigens. Values for cell- and serum-mediated cytotoxicity against melanoma cells and the response of the patient's lymphocytes to phytohemagglutinin were slightly above the normal range. A review of the literature reveals 13 other cases of long-term spontaneous regression of melanoma. None of these, however, had biopsy evidence of visceral disease. In each of the 13 cases, regression was associated with an event that might be inferred to have altered the patient's hormonal or immune status. This patient also provides evidence of a complete, spontaneous, and long-term remission of metastatic disease associated with the spontaneous development of host immunity.