Localized necrotizing angiitis of the ileum

A 20-year-old woman was hospitalized repeatedly because of intermittent bouts of intestinal obstruction and the symptoms usually improved with conservative treatments. One year after the first admission the patient was hospitalized in emergency and a laparotomy revealed a circular stricture with a pinhole perforation in the ileum. Histological sections of the stricture showed the characteristic features of microscopic polyangiitis varying from active to resolving stages, which were localized in the ileum. Fibrinoid necrosis, fibroblastic and fibrous proliferation of the intima and fibrous replacement of the media with a variable pan- and perivascular inflammatory cell infiltrate were characteristic in the muscular arteries and arterioles. Vascular occlusion by pale eosinophilic, fibrillar-like materials resembling livedo racemosa of the skin, was noticed in the small arterioles and capillaries. Under no prophylaxis, the postoperative course was uneventful with no recurrence of the illness at an 18-month follow up. The pathological alterations were distributed focally, occasionally segmentally, and haphazardly, and required detailed examination by stepwise sections for the histological diagnosis.