We conducted a clinicopathologic study of eight cases of angiolymphoid hyperplasia with eosinophilia (Kimura's disease). The orbit was involved in five patients and the ocular adnexa (eyelid and inner canthus) in three. The median age of the six men and two women was 51 years (range, 38 to 72 years). The lesions were characterized by an abnormal proliferation of small vessels lined by plump endothelial cells, associated with a chronic inflammatory infiltrate with prominent tissue eosinophilia and scattered lymphoid follicles. Serial sectioning of two tumors disclosed that these small vessels apparently originated within the walls of arteries. Immunohistochemistry disclosed factor VIII-related antigen within the endothelial cells in two of the four lesions studied. Ultrastructurally, some of the capillaries showed prominent multilaminar basement membranes surrounding their walls. The apical surface of the markedly swollen endothelial cells disclosed broad villous processes protruding into the lumen. Although this vascular lesion can be mistaken for angiosarcoma, it is considered benign. There was no evidence of recurrences of any of the six of the seven lesions that were completely excised and followed up (follow-up periods ranged from five to 95 months). Complete surgical excision appears to be the best treatment.