A 59-year-old-male was admitted in September 1984 with fever and right hypochondrial pain. On computed tomography, a bulky retroperitoneal tumor involving the intestine was detected. Exploratory laparatomy yielded a diagnosis of non-Hodgkin's lymphoma. Although intensive and aggressive treatment combined chemotherapy and radiotherapy was administered, no conclusion could be drawn about its efficiency, and no remission was indicated by followup studies. He refused further treatment because of bone marrow depression. However, 9 months after the last treatment disappearance of the tumor was recognized on computed tomography examination. This phenomenon was confirmed by the second laparatomy performed in order to treat skin-colon fistula caused from diverticulitis of the colon. It was recognized no evidence of malignant lymphoma in the resected colon specimen. He remains in excellent health 26 months after this events. The clinical course of this case was probably compatible with the concept of spontaneous remission of malignant lymphoma.