Background: We experienced a case in which Cronkhite-Canada Syndrome presented with complications of multiple gastric cancers and multiple colon adenomas.
Case Report: Our case is a 64-year-old male who visited a nearby hospital with diarrhea and weight loss. The patient was anemic and hypoproteinemic, with multiple polyps in the stomach, duodenum, and large intestine. He also presented with alopecia, onychatrophia, cutaneous pigmentation, and dysgeusia, and was diagnosed with Cronkhite-Canada Syndrome. Follow-up examinations found multiple gastric cancers and colon adenomas. We performed a total gastrectomy and a polypectomy of the large intestine lesions, revealing 4 well-differentiated adenocarcinomas in the resected stomach, and tubular adenomas in the large intestine lesions. Intraoperative findings included scattered melanoid pigmentation on the mesentery and the small intestinal wall. Tumor cells were positive for p53 and Ki67 and partially positive for MUC5AC and MUC2. Cronkhite-Canada Syndrome polyps are generally classified as juvenile type polyps, and these polyps rarely become cancerous. However, of the 383 cases of Cronkhite-Canada Syndrome reported in Japan, complications of gastric cancer were found in 39 cases (10.2%), and only 8 cases with multiple gastric cancer were reported in Japan. including the cases we have personally experienced. There were only two English literatures on Cronkhite-Canada Syndrome complicated with gastric cancer. So it is necessary to notify this information of Cronkhite-Canada Syndrome to the world.
Conclusions: Close gastrointestinal examination and strict follow-up are believed to be essential for Cronkhite-Canada Syndrome patients.

Keywords: colon adenoma, gastric cancer, Cronkhite-Canada syndrome