Retroflexion of the sigmoidoscope for the detection of rectal cancer.

Flexible sigmoidoscopy is a procedure that is commonly used by primary care physicians for the evaluation of rectal disorders and for colorectal screening. Retroflexion of the endoscope improves views of the anorectum and rectal vault, which increases the diagnostic yield of sigmoidoscopy. We report three cases of rectal lesions that were not detected when flexible sigmoidoscopy was performed without retroflexion. The lesions were all malignant or premalignant. The illustrative cases demonstrate the value of retroflexion in flexible sigmoidoscopy for the detection of rectal lesions.