Narrow‐band imaging with magnification for the diagnosis of colorectal adenoma in a patient with Cronkhite‐Canada syndrome

Cronkhite‐Canada syndrome (CCS) is a rare disease characterized by gastrointestinal polyposis, skin pigmentation, alopecia, and abnormal nailfolds. Although colorectal cancer has been reported in patients with CCS, reports are limited regarding the effectiveness of the usage of image‐enhanced endoscopy in CCS lesions. Here, we report a case of CCS in which narrow‐band imaging (NBI) magnifying endoscopy was applied to detect an adenomatous component in multiple hamartomatous polyps. A 79‐year‐old female complained of taste disorder, anorexia, and weight loss over several months. Endoscopic examination revealed multiple reddened polyps in the stomach and colon, leading to a diagnosis of CCS. Narrow‐band imaging magnification showed sparse and dilated round pits on the CCS polyps. Furthermore, 12 out of the numerous colorectal CCS polyps had a coexisting light reddish elevated component with a regular distribution of microvessels and a regular reticular pattern. This pattern satisfied the criteria for Type 2A of the Japan Narrow‐band‐imaging Expert Team classification, indicating adenoma. After resection, these twelve polyps were subject to pathological analysis, which confirmed they were all hamartomatous polyps with low‐grade adenoma on the superficial layer. Immunohistochemical analysis revealed a significant increase in the Ki‐67 index and p53 staining only in the adenomatous lesions. We conclude that narrow‐band imaging magnifying endoscopy would be useful in differentiating adenoma from CCS‐related polyps, which thereby facilitates early detection and treatment of precancerous lesions.