OBJECTIVE Cronkhite-Canada syndrome (CCS) is a non-inherited, sporadic disorder characterized by generalized gastrointestinal polyps (hamartomas), cutaneous pigmentation, alopecia and onychodystrophy. More than 500 CCS patients have been reported, mostly from Asian countries. Patients with CCS have a propensity to develop colonic traditional serrated adenomas (TSA). Some authors found increased frequency of colonic carcinomas in CCS patients. In the present communication, we report a patient with CCS in whom a colonoscopic examination failed to disclose a coexistent TSA. METHODS A 73-year-old female had a history of alopecia and nail atrophy. Because of iron deficiency anemia and occult gastrointestinal bleeding, she underwent a colonoscopic examination. RESULTS Colonoscopy revealed multiple broad-based polyps. Due to continuous bleedings, a coloproctectomy was performed four months after colonoscopy. Pathology disclosed 50 hamartomas and, unexpectedly, a TSA with high-grade dysplasia in the cecum. CONCLUSIONS The TSA was either overlooked at colonoscopy or not interpreted as different from the other colonic polyps by the endoscopist. CCS cases are very rare in Western countries. Given this circumstance, it is suggested that, when confronting the next CCS case, endoscopists should perform a comprehensive colonoscopic examination, including chromoscopy and directed biopsies from irregular polyps, to rule out a TSA, an adenoma prone to evolve into invasive carcinoma.