Malignant lymphoma presenting as Kaposi's sarcoma in a homosexual man with the acquired immunodeficiency syndrome.

A homosexual man had Kaposi's sarcoma of the skin and lymph nodes. After a brief response to interferon, the patient developed new skin lesions. Massive bleeding in the gastrointestinal tract prompted endoscopy, which showed tumor involvement of the stomach, believed to be Kaposi's sarcoma. At autopsy, a diffuse lymphoma was found involving the skin and gastrointestinal tract, forming collision tumors in regions that contained Kaposi's sarcoma. Lymphomatous tissue, but not uninvolved lymph node or spleen, contained Epstein-Barr virus DNA, as shown by DNA hybridization studies. Epstein-Barr virus may play a role in the development of lymphoma in immunosuppressed patients. Unusual manifestations of tumors, such as the massive gastrointestinal bleeding seen in this case, may indicate the development of a second neoplasm.