Nonhereditary colonic angiodysplasias: histomorphometric approach to their pathogenesis.

The pathogenesis of colonic angiodysplasias, more accurately termed vascular ectasias (VE) has not been definitely established. The aim of this study was to assess that the VE of noncirrhotic patients are not associated with diffuse abnormalities of the colonic mucosal microvasculature unlike the VE of cirrhotic patients. Three groups of nine consecutive patients were studied: group I, control patients with an irritable bowel syndrome; group II, noncirrhotic patients with VE; and group III, alcoholic cirrhotics with VE. A histomorphometric analysis of normal-appearing colonic mucosa was achieved from biopsies taken at six predetermined sites. Noncirrhotics with VE had a significantly lower mean number of mucosal capillaries and a significantly lower mean cross-sectional area of mucosal capillaries than alcoholic cirrhotics with VE. Alcoholic cirrhotics with VE had a significant increase of all the vascular parameters compared to the control group. There was no difference between the control patients and the noncirrhotic patients with VE. These results suggest that the VE of noncirrhotic and cirrhotic patients are entities of distinct pathogenesis.