Aneurysmal dilatation of colon: A rare imaging presentation of colon cancer.

Aneurysmal dilatation of colon is a rare imaging feature of colon adenocarcinoma. Two cases with massive aneurysmal dilatation of the colon secondary to moderately differentiated adenocarcinomas are described. The 2 cases presented with asymmetric and progressive abdominal distension with no obstructive symptoms. Contrast-enhanced computed tomography of the abdomen and pelvis demonstrated marked aneurysmal dilatation of the involved segments of the colon and circumferential mural thickening. Colonoscopy found markedly dilated lumen in the involved segment of the colon. Histology of the biopsy specimens taken during colonoscopy revealed moderately differentiated adenocarcinoma with extensive infiltration of colon wall and damage of myenteric nerve plexus.