Benign Lesion of the Common Bile Duct Mimicking a Malignant Tumor: an Entity Commonly Overdiagnosed Clinically.

Adenomyomatous hyperplasia and adenomyoma are rare benign inflammatory pseudotumors of the gallbladder arising from Rokitansky-Aschoff sinuses. Occurrence of these hyperplastic conditions in the Vaterian and biliary system is extremely rare and is a concern for gastroenterologists and surgeons in distinguishing them from primary malignancies of the biliary system. Definitive diagnosis by imaging or cytopathological examination is difficult; thus, surgical resection becomes the only choice in such cases to relieve the obstruction. Here, we report two extremely rare cases of adenomyomatous hyperplasia of the extrahepatic bile duct after an extensive diagnostic workup, followed by Whipple's procedure.