Small bowel obstruction due to an unconjugated ursodeoxycholic acid enterolith following living donor liver transplantation: Report of a case.

We report an unusual case of small bowel obstruction due to an ursodeoxycholic acid (UDCA) enterolith that occurred 7 years after liver transplantation. A 70-year-old man had undergone multiple operations, including a living donor liver transplantation (LDLT) and hepaticojejunostomy. Four years after the LDLT, cholestasis developed, for which oral UDCA was administrated. Seven years after the LDLT, he was admitted to our hospital because of pneumonia; intestinal obstruction occurred following its resolution. A radiographic contrast study and computed tomographic scan indicated a movable mass as the cause of the ileus, suggesting a giant stone. We were unable to observe or remove the stone by double balloon enteroscopy owing to the presence of severe adhesion; thus, we surgically removed the mass. The patient's postoperative course was uneventful. He was discharged 20 days after the operation. An infrared spectrophotometric analysis revealed that the stone was a true enterolith, primarily composed of unconjugated UDCA. An ileus caused by a true enterolith is a rare clinical complication of LDLT. Nevertheless, it must be considered in the differential diagnosis of intestinal obstructions in liver transplant recipients with Roux-en-Y hepaticojejunostomies and/or bowel stasis.