Barium enema "shoulder" sign: A useful predictor of pericolonic fat invasion in colorectal cancer

Purpose We aimed to determine the presence of the "shoulder" sign in prediction of pericolonic fat invasion on double-contrast barium enema (DCBE) studies in colorectal cancer. Materials and methods Patients at our institution with apparent colorectal cancer were identified from a computer search of both radiological and surgical pathology records during a recent 30-month period. The presence of a shoulder sign was defined as a tumor margin having an abrupt transition from the intraluminal component to the adjacent normal mucosa, forming a shouldered edge on barium studies. Results A total of 49 patients (53 lesions) for whom the DCBE studies and surgical pathology records were available for review were proven to have colorectal carcinomas. DCBE studies revealed that 45 patients with lesions (85%) presented with a "shoulder" sign. All of these lesions were correctly diagnosed as colorectal cancer. Of these, 89% had pericolonic fat invasion and 44% had regional lymph node metastases. Of lesions without a shoulder sign, 25% had pericolonic fat invasion and 25% had nodal metastases. Conclusion The presence of shoulder sign detected with barium enema can be a useful predictor of pericolonic fat invasion in colorectal cancer.