Gallstones and their composition in patients with ileoanal anastomosis.

Cholelithiasis is known to occur in 15%-24.5% of proctocolectomized patients. However, the clinical features and chemical analysis of gallstones in these patients have not been reported. We describe two cases of cholelithiasis that developed in patients after proctocolectomy with ileoanal anastomosis. These patients had a high output of watery stools and more frequent bowel movements than the average for Japanese patients with ileoanal anastomosis. The chemical composition of the resected gallstones was 93.0% cholesterol and 80.9%, respectively, in the two patients, indicating that cholesterol gallstones are formed in patients with ileoanal anastomosis after proctocolectomy.