A patient with rectal cancer associated with ulcerative colitis in whom endoscopic ultrasonography was useful for diagnosis

Endoscopic ultrasonography (EUS) was helpful for the diagnosis of rectal ca ncer associated with ulcerative colitis. The patient was a 38-year-old Japa nese man with a 19-year history of relapsing-remitting type ulcerative coli tis involving the entire colon. Routine colonoscopy revealed multiple polyp oid prominences in the upper portion of the rectum. EUS revealed a hypoecho ic mass in the submucosa beneath and around the polypoid lesion on the most oral side. Signet ring cells were found in a biopsy specimen from this les ion. Subtotal colectomy was performed. A depressed lesion was observed arou nd the prominence on the most oral side; histologically, this lesion was po orly differentiated mucinous and signet ring cell carcinoma extending into the subserosa. The polypoid lesion on the most anal side was well different iated adenocarcinoma, which was limited to the mucosa. Our findings suggest that EUS is helpful for detecting invasive cancer associated with ulcerati ve colitis.