A case of granulomatous giant cell phlebitis occurred in the mesenteric veins of a 38-year-old man, resulting in segmental infarction of the ileum. Multiple epithelioid granulomas with giant cells of the Langhans type were situated in media/adventitia of small and middle-sized mesenteric veins with subsequent thrombotic venous occlusions. No involvement of arterial vessels could be detected. The aetiology of the disease remains unknown. Known types of vasculitis were excluded. It was assumed that this is an example of in immunological vasculopathy but this could not be proved.