Clinicopathological study of a patient with idiopathic villous atrophy and small vessel alterations of the ileum.

Ileal villous atrophy with normal proximal small intestinal mucosa is a rare lesion observed in a few diseases. We report here a case of unknown etiology. A 49-year-old woman presented with chronic diarrhea and steatorrhea due to bile acid malabsorption which was strikingly improved by a low-fat diet. Villous atrophy was total or subtotal, but enterocyte alterations were minimal. Crypts were hyperplastic and the lamina propria was infiltrated by lymphocytes and plasma cells mainly synthesizing IgM. These alterations were associated with the presence in the submucosa, and occasionally in the mucosa, of numerous convoluted nonectasic capillary tufts. Thrombi consisting of pure platelet aggregates were found in the capillary tufts and adjacent small vessels, whose walls were either normal or hyalinized. The patient suffered for many years from attacks of Raynaud's phenomenon and platelet aggregation was depressed in the presence of collagen. Thrombi disappeared after aspirin treatment, but the other lesions persisted at the time of death from an unrelated cause.