Preoperative diagnosis of a small, depressed rectal cancer complicating ulcerative colitis. Report of a case

This study was designed to clarify the importance of detecting small, depressed colorectal cancer complicating ulcerative colitis.

A 39-year-old Japanese male, who had an 18-year history of left-sided ulcerative colitis, was admitted to Fukuoka University Hospital for further evaluation of his colitis. Colonoscopy with a dye spraying method clearly revealed a small, depressed lesion and flat plaque-like lesions in the rectum. Biopsies taken from a depressed lesion and plaque-like lesions revealed a signet-ring cell carcinoma and dysplasia, respectively. Total colectomy was performed.

Sections from the depressed rectal lesion, measuring 7 x 8 mm in size, revealed a signet-ring cell carcinoma that diffusely invaded the muscularis propria. Lymph node metastasis was evident. Flat plaques and mucosa around the depressed lesion were positive for dysplasia.

This is the first report of a case of small, depressed rectal cancer complicating ulcerative colitis diagnosed by preoperative colonoscopy. To improve outcome of colonoscopic surveillance in ulcerative colitis, detecting such small, depressed lesions are important, and colonoscopy with a dye spraying method would be useful in detecting them.