Adenomyoma of the ampulla of Vater: an uncommon cause of bile duct obstruction.

Adenomyomas of the bile ducts are extremely rare. They are most likely often overlooked also when situated in the ampulla of Vater and obstructing bile flow. Of 3,131 endoscopic retrograde cholangiograms, four patients with ampullary adenomyoma and signs of biliary obstruction have been diagnosed. When recognized they can be treated effectively by endoscopic means. However, their radiologic and endoscopic appearances were found difficult to interpret and led to unnecessary endoscopic sessions in one patient and surgery in another. Thus, increased awareness of this entity is important to avoid overlooking or misdiagnosing it.