An adult choledochocele case presenting with unexplained biliary colic: Awareness of endoscopic feature is important

Type III choledochal cyst (choledochocele) is a rare disease. Therefore, some endoscopists are not familiar with the clinical feature of choledochocele. We present a choledochocele case that was difficult to diagnosed until endoscopic retrograde cholangiopancreatography was performed. A 46-year-old Taiwanese gentleman had unexplained biliary colic pain with negative findings of physical examination and normal laboratory tests. Magnetic resonance cholangiopancreatography and endoscopic ultrasonography showed dilation of common bile duct (CBD) about 1.8 cm without choledocholithiasis and a cystic lesion at distal CBD about 0.9 cm. The endoscopy showed a cystic-like bulging structure above the ampullary orifice. Cholangiography showed cystic enlargement of the intramural bile duct superior to the ampullary orifice after contrast injection. Choledochocele was proved. We performed papillotomy and biopsy of the papilla. Awareness of the endoscopic feature and management strategy of choledochoele is important, which is illustrated in this case report.