Spontaneous sump syndrome: Successful treatment by duodenoscopic sphincterotomy. "Sump syndrome" is a rare complication of side-to-side choledochoenterostomy operations which develops in the distal, nonfunctioning limb of the common bile duct where lithogenic bile, gastrointestinal contents, and debris accumulate. We report here a patient who developed spontaneous sump syndrome as a result of the formation of choledochoduodenal fistula, and who presented with multiple pyogenic liver abscesses. The patient's symptoms and liver abscesses resolved completely after treatment by endoscopic sphincterotomy and antibiotics. This case demonstrates that sump syndrome may occur spontaneously, that it can be a cause for pyogenic liver abscess formation, and that it may be treated effectively by endoscopic sphincterotomy. 