['The management of gallbladder polyps/masses in patients with primary sclerosing cholangitis (PSC) (i.e., cholecystectomy vs observation) remains problematic. Given the risk of biliary tract cancer in PSC in the face of the benign nature of most gallbladder polyps in the general population, our aim was to determine the prevalence of gallbladder cancer in PSC patients with a gallbladder mass who had undergone cholecystectomy.', 'The case records of all patients with PSC undergoing a cholecystectomy at the Mayo Clinic between 1977-1999 were reviewed.', 'Of the 102 patients with PSC who underwent a cholecystectomy, 14 of 102 (13.7%) had a gallbladder mass. In the subset of patients with gallbladder masses, eight of 14 (57%) had adenocarcinomas (seven primary adenocarcinomas and one metastatic cholangiocarcinoma); the other six had benign masses (five adenomas and one cholesterol polyp). In those patients with benign masses, 33% had associated epithelial cell dysplasia; in patients with primary gallbladder cancers, 57% had associated dysplasia. The patients with primary gallbladder adenocarcinoma had a favorable outcome after cholecystectomy, with a 36-month survival of 66%.'] Are in primary sclerosing cholangitis , gallbladder polyps frequently malignant?