Introduction
Ulcerative colitis (UC) is a chronic relapsing inflammatory disorder of the colon (13). Patients with UC have an increased risk for developing colorectal cancer (CRC), known as UC-associated CRC (3, 8, 18). The cumulative incidence of UC-associated CRC has been reported to be from 7.5% to 18.4% at 30 years after onset (20). However, appendix adenocarcinoma associated with UC is extremely rare.