The angiographic diagnosis of colonic carcinoma

Carcinoma of the colon is a common cause of chronic iron deficiency anaemia in elderly patients and is conventionally diagnosed by either barium enema or colonoscopy. Occasionally these studies are inconclusive and individuals may proceed to further imaging, including angiography. Between December 1991 and October 1996, 337 patients were referred for visceral angiography to determine the cause of chronic gastrointestinal bleeding. In seven of these individuals (two males and five females with an age range of 65-74 years), all of whom had been investigated by barium enema and colonoscopy, both reported as showing no cause for bleeding, an arteriographic diagnosis of colonic carcinoma was made. Four of these demonstrated patchy areas of increased vascularity whilst three were predominantly hypovascular. Early venous drainage was seen in five. Marked irregularity and truncation of vasa rectae was present in six; more subtle irregularity was visible in one. The mural veins were irregular with or without truncation in five of the six patients in whom they were visualized. The marginal artery was angiographically involved in only two cases and in one of these the tumour was irresectable. It is important to recognize that a previous 'normal' colonoscopy and barium enema does not exclude a colonic neoplasm, even if advanced, and that this diagnosis may be made angiographically. Confusion with other pathologies, such as angiodysplasia, should be prevented by close scrutiny of vasa rectae at the site of arteriographic abnormality, which will usually demonstrate vascular irregularity and truncation highly suggestive of malignancy.