Brunner's gland hamartoma: a cause of the double-duct sign

Introduction Brunner's glands are submucosal glands found in the duodenum. Proliferation of these glands can lead to the formation of Brunner's gland hamartomas (BGHs), which are uncommon, asymptomatic and usually found incidentally. They are predominantly benign lesions, but instances of malignant transformation have been reported. Case History We describe a rare case in which a periampullary lesion was causing biliary obstruction on a background of weight loss, and was associated with dilatation of the common bile duct and pancreatic duct on computed tomography and magnetic resonance imaging. Further investigation with endoscopic ultrasound and biopsy did not provide a definitive diagnosis. Given the symptoms and findings upon investigations, we proceeded to pylorus-preserving pancreatoduodenectomy. Conclusions This was a rare case in which BGH gave rise to biliary obstruction against a background of weight loss. Due to a high index of suspicion (weight loss and evidence of dilatation of the common bile duct and pancreatic duct), this procedure was justified because the consequences of a missed periampullary cancer far outweighed surgical risks.