A rare case of a ciliated hepatic foregut cyst with progressive enlargement causing obstructive jaundice

A 73-year-old woman presented with a 10-day history of anorexia, and laboratory tests revealed obstructive jaundice. Imaging studies showed biliary obstruction caused by a 40‑mm unilocular cystic lesion in hepatic segment 4. The lesion had first been identified 10 years earlier and enlarged over the preceding 5 months. Endoscopic retrograde cholangiopancreatography (ERCP) was performed. Cholangiography revealed a compressive stricture of the bile duct near the hepatic hilum, with complete obstruction of the right intrahepatic bile duct and stenosis of the left intrahepatic bile duct. A biliary stent was placed in the left intrahepatic bile duct. The enlargement of the cystic lesion raised suspicion of malignant involvement. Given the obstruction of the right intrahepatic bile duct, infiltration or adhesion of the cystic lesion to the right intrahepatic bile duct was suspected. An extended right hepatectomy was safely performed, and the lesion was pathologically diagnosed as a ciliated hepatic foregut cyst (CHFC). CHFCs are congenital cystic lesions, that originate from the embryonic foregut. Given the rarity of CHFCs, their natural history and clinical behavior remain poorly understood. CHFCs were traditionally regarded as benign and often managed conservatively. However, recent reports of squamous cell carcinoma arising within CHFCs have raised concerns, and surgical resection is recommended when malignant transformation is suspected. This is the first reported case of a CHFC that remained stable for many years, then rapidly enlarged and caused obstructive jaundice. When CHFCs are identified, clinicians should consider the risks of potential rapid enlargement even without malignant transformation.