Résumé : The authors report a case of generalised Kaposi sarcoma complicated by pulmonary cryptococcosis and cerebral toxoplasmosis. Clinical features were dominated by the cerebral condition. The infectious pathogenesis could be related to disturbances in immune defences. Ultrastructural study revealed the presence of several types of tumour cells. Endothelial cells formed vascular lumens and contained Weibel-Palade granules and reticulo-tubular inclusions.