2021 Volume 63 Issue 7 Pages 1371-1378
A 60-year-old man visited our hospital with a chief complaint of frequent diarrhea containing mucus and blood for the previous two weeks. The initial colonoscopy showed multiple erythematous lesions covered with mucus in the rectum and varioliform lesions from the transverse colon to the sigmoid colon. As a definitive diagnosis was not made, he was followed up for non-specific colitis. Four months later, his condition deteriorated, and his stool frequency was more than 40 times daily. The second colonoscopy showed erythematous lesions extending from the rectum to the sigmoid colon, and the rectal erythematous lesions had developed a flat-topped protrusion. These endoscopic findings were consistent with those atypically observed in patients with cap polyposis (CP). Thus, this patient was diagnosed with CP. After Helicobacter pylori eradication therapy, his condition and endoscopic findings showed remarkable improvement. Occasionally, the typical endoscopic findings of CP are not observed depending on the stage of the disease. Therefore, establishing a diagnosis of CP can be difficult. It is important to be familiar with the atypical findings of CP for early diagnosis.
