Diabetic microangiopathy in the small bowel

Aims: Microangiopathic changes in the gastrointestinal tract of patients with diabetes mellitus are frequently mentioned in the clinical literature. To our knowledge, pathological studies documenting these changes in bowel biopsies have not been previously reported. In this report, we describe striking duodenal biopsy findings of diabetic microangiopathy in a patient with long-standing insulin-dependent diabetes mellitus and chronic diarrhoea. Methods and results: The diagnosis was based on the histopathological and immunohistochemical findings in the appropriate clinical setting. Blood vessels within the duodenum displayed prominent mural thickening and luminal narrowing secondary to accumulation of hyaline material, which was periodic acid-Schiff positive and intensely stained with monoclonal antibodies against type IV collagen. Conclusions: This is the first report of diabetic microangiopathy in a bowel biopsy. The pathogenesis, specificity and significance of these angiopathic changes, controversies about diabetic microangiopathy in the gastrointestinal tract, and the association with hypertension are discussed.