Bile Salt Enterolith: An Unusual Etiology Mimicking Gallstone Ileus.

Primary enterolithiasis is a relatively uncommon but important cause of small bowel obstruction. We present a case of a 69-year-old male with a history of laparoscopic Roux-en-Y gastric bypass and asymptomatic duodenal diverticulum diagnosed with small bowel obstruction. CT imaging showed an obstruction distal to the jejunojejunostomy, and surgical intervention was warranted. A 4.5 cm enterolith removed from the distal jejunum was found to contain 100% bile salts, consistent with a primary enterolith. Clinicians should retain a high index of suspicion for enteroliths as a cause of small bowel obstruction, especially if multiple risk factors for enterolith formation are present.