Epithelioid angiomatosis, hemangioma-like vascular proliferations recently described in AIDS patients, has been associated with the cat scratch disease bacillus. Other vascular lesions present in AIDS patients, in particular Kaposi's sarcoma, have been associated with cytomegalovirus (CMV). We investigated the possibility of viral association with epithelioid angiomatosis by analyzing two such lesions, as well as unrelated concurrent skin lesions, for the presence of viral genetic information. Colorimetric in-situ hybridization was performed on formalin-fixed, paraffin-embedded sections using cloned biotinylated probes for CMV, herpes simplex virus, human immunodeficiency virus, and Epstein-Barr virus (EBV). The only virus demonstrated was EBV, and this was only in the two epithelioid angiomatosis lesions. Hybridization signal for EBV was present in the nuclei of endothelial cells and occasional histiocytes. Bacilli were demonstrated within one of the lesions by silver stain. This is the first report associating EBV with this entity, and the first-time demonstration of EBV genetic information in endothelial cells. Our data suggest that these vascular lesions may represent a nonspecific response to infection by many different agents, and that EBV may be involved in the pathogenesis of some of these lesions.