Purpose To explore the clinicopathological features and endoscopic manifestations of cap polyposis(CP).Methods Clinical,endoscopic,pathological,and follow-up data of 17 cases of CP were collected and ana-lyzed.Results There were 14 males and 3 females,aged 15-67 years,with a mean age of 36.5 years.The disease duration ranged from 2 weeks to 5 years,and most patients(64.7％,11/17)had symptoms for more than l year.The most common clinical manifestation was hematochezia(82.4％,14/17),while constipation was generally absent.En-doscopically,all lesions(100％,17/17)were located in the anal canal and lower rectum.The surface was invariably covered with a thick whitish exudate(100％,17/17),and annular growth was the most frequent pattern(76.5％,13/17).Pathologically,the mucosal layer was almost entirely replaced by granulation tissue,and the surface showed extensive inflammatory necrosis forming a cap-like structure.Conclusion CP predominantly occurrs in the anal canal and lower rectum of young men.The presence of abundant whitish exudate under endoscopy is differential diagnostic value.Complete endoscopic resection followed by pathological examination is required for definitive diagnosis.

Purpose To explore the clinicopathological features and endoscopic manifestations of cap polyposis(CP).Methods Clinical,endoscopic,pathological,and follow-up data of 17 cases of CP were collected and ana-lyzed.Results There were 14 males and 3 females,aged 15-67 years,with a mean age of 36.5 years.The disease duration ranged from 2 weeks to 5 years,and most patients(64.7％,11/17)had symptoms for more than l year.The most common clinical manifestation was hematochezia(82.4％,14/17),while constipation was generally absent.En-doscopically,all lesions(100％,17/17)were located in the anal canal and lower rectum.The surface was invariably covered with a thick whitish exudate(100％,17/17),and annular growth was the most frequent pattern(76.5％,13/17).Pathologically,the mucosal layer was almost entirely replaced by granulation tissue,and the surface showed extensive inflammatory necrosis forming a cap-like structure.Conclusion CP predominantly occurrs in the anal canal and lower rectum of young men.The presence of abundant whitish exudate under endoscopy is differential diagnostic value.Complete endoscopic resection followed by pathological examination is required for definitive diagnosis.