Utility of specimen angiography in angiodysplasia of the colon.

This study reviews the utility of specimen angiography in identifying colonic lesions clinically thought to represent angiodysplasia. Four elderly patients presented with acute rectal bleeding. The diagnosis of angiodysplasia was made preoperatively in 3 patients by colonoscopy or angiography, or both. These specimens were injected with silicon rubber compound, xerographed, cleared with methyl salicylate, and examined with transillumination before histologic sampling. Although this technique was not used in the fourth case, fortuitous random sampling of the ascending colon revealed vascular changes indicative of angiodysplasia that correlated with a preoperative bleeding scan. Associated lesions in 1 patient were carcinoma of the colon and primary amyloidosis, the concurrence of which has not been described previously. With the injection technique the lesions of angiodysplasia appear grossly as spiderlike, dilated blood vessels. Microscopically, dilated veins, venules, and capillaries are found in the submucosa only or in the mucosa and submucosa. The importance of the postoperative injection is that it prevents the collapse of the blood vessels and enables the pathologist to identify the lesions grossly. As these lesions are usually small, this is important for proper sampling and histologic documentation.