A 48-year-old homosexual with contacts in different countries, including Haiti, presented with multiple pigmented or bluish nodules on both lower legs and upper arms. He had a history of secondary syphilis, hepatitis B and herpes zoster ophthalmicus. Biopsies of the skin tumors revealed a typical Kaposi's sarcoma of low grade malignancy. The endothelial origin of the tumor was indicated by the presence of specific endothelial organelles (Weibel-Palade bodies) in the cytoplasma of the tumor cells. Erythrocyte phagocytosis was found in tumor cells within and without the vascular channels. Laboratory tests were compatible with the clinical diagnosis of an acquired immune deficiency syndrome (AIDS) with a helper: suppressor T-lymphocyte ratio of 0.28 and a cutaneous anergy. In the course of the illness tumors of the stomach and duodenum were detected. Histology showed a malignant non-Hodgkin lymphoma of high grade malignancy. Within weeks the patient died in a cachectic state. Autopsy revealed a Kaposi's sarcoma of the skin with metastases in the stomach and a wide-spread malignant lymphoma in the gastrointestinal tract, in several visceral organs and in many lymph nodes.