(14-RES) Not All That Is Dilated Is Obstructed: A Rare Case of Type Ic Choledochal Cyst

Clinical Scenario or Case: A 27-year-old female with no significant past medical history presented with acute right upper quadrant (RUQ) pain radiating to the back, associated with nausea, vomiting, chills, and diaphoresis. She reported intermittent similar episodes over several years, typically self-resolving, but this time persistent. CT imaging revealed fusiform dilation of the common bile duct (CBD) measuring 41 mm without intrahepatic ductal dilation or obstructive mass. MRCP confirmed a Type Ic choledochal cyst. The patient underwent elective open resection of the extrahepatic bile duct with a Roux-en-Y hepaticojejunostomy, cholecystectomy, and pancreatorrhaphy. She recovered uneventfully.

Evidence/Literature Review: Choledochal cysts are rare congenital malformations of the biliary tree, with Type I cysts (especially Type Ic) being the most common. These cysts pose a significant long-term risk of complications, including cholangitis, pancreatitis, and malignancy—particularly cholangiocarcinoma, with lifetime risk reported up to 15% in untreated cases. The standard of care is complete surgical excision of the cyst and biliary reconstruction. MRCP remains the imaging modality of choice for diagnosis and classification.

Unique Aspects of Case: - Late diagnosis of a congenital Type Ic choledochal cyst in an adult.
- Absence of obstructive symptoms despite massive CBD dilation.
- Elective surgical resection performed prior to onset of malignant transformation or hepatobiliary complications.
- Use of a round ligament flap to reinforce hepaticojejunostomy—an advanced surgical technique not routinely employed.

Recommendations/Conclusions: In adult patients presenting with recurrent RUQ pain and bile duct dilation without obstruction, choledochal cysts must remain a diagnostic consideration. Early MRCP and multidisciplinary evaluation are key. Elective surgical intervention in asymptomatic patients is justified to reduce the risk of long-term malignancy and biliary complications.