INVESTIGATION: Moderate yellowing of the skin and mucous membranes throughout the body, sclera in both eyes, marked right epigastric tenderness, no palpable mass, MURPHY (+). Laboratory tests: positive Casoni test. Albumin transaminase (ALT) 154 IU/L, AST 85 IU/L, total bilirubin (TBIL) 247.4 μmol/L, direct bilirubin (DBIL) 161.9 μmol/L, indirect bilirubin (TB-DB) 85.50 μmol/L. Ultrasound report: rounded, fluid-dark area, size about 10 cm. Liquid dark area, size about 10.8cm×9.3cm, thick wall, complete, clear margins, poor internal permeability, visible mass of strong echoes. Bilateral sign of gallbladder, mud-like strong echoes were seen in the lumen. Dilatation of intrahepatic and extrahepatic bile ducts, the diameter of common bile duct was about 2.0 cm, and granular strong light spots were seen in it.Diagnosis by ultrasound: 1, hepatic encrustation in the right lobe of the liver; 2, gallbladder stones, cholecystitis; 3, multiple stones in the common bile duct with obstructive dilatation of intrahepatic and extrahepatic bile ducts. MRI: A large round cystic space-occupying lesion was seen in the posterior segment of the right lobe of the liver, with a size of about 10.2cm×10.0cm×10.0cm (anterior-posterior×uperior-inferior×left-right). The peritoneum was clear and low-signal, the intracapsular T1WI was low-signal, T2WI was high-signal, and the signals were mixed, and most of the banded and granular low-signal shadows were seen within it. At the level of the right hepatic duct in axial and coronal positions, the intrahepatic bile duct was obviously dilated, and the dilated right hepatic duct communicated with the intrahepatic cystic lesion, forming an internal fistula, and the right hepatic duct and dilated extrahepatic bile duct were filled with most small granular low-signal foci. A low-signal stone was seen in the distal part of the dilated common bile duct. MRI diagnosis: 1, hepatic encapsulation in the right lobe of the liver and internal fistula with the right hepatic duct; 2, stone in the distal common bile duct and obstructive dilatation of the intrahepatic bile duct; 3, cholecystitis and gallbladder stone. Intraoperative findings and pathologic results: a huge cystic mass was seen in the right lobe of the liver, and the cyst wall was incised to show a large number of cysts and cystic wall tissues within the cyst. The common bile duct was incised and found to be filled with cyst wall tissue and cysts, and a stone was seen at the distal end; the common bile duct to the right hepatic duct was explored, and the right hepatic duct was found to be connected with the cavity of the cyst, forming an internal fistula, from which the cyst wall tissue and cystic fluid entered the common bile duct. Pathologic diagnosis: (right lobe of the liver) hepatic encapsulation. Discussion: Baucellosis double name echinococcosis, is the human infection of echinococcus tapeworm larvae caused by the disease of the general term. Subdivided into: fine-grained echinococcus and follicular echinococcus, with fine-grained echinococcus common. Mainly prevalent in animal husbandry areas, is a zoonotic disease, humans are one of its intermediate hosts. Hepatic cysticercosis is the most common, mostly located in the right lobe of the liver. The intracapsular tension of liver cysts is very high, and rupture is a common and serious complication, but it is rare for liver cysts to break into the intrahepatic bile ducts and form an internal fistula. In this case, the MR imaging was typical, and the fistula was more clearly shown by T2WI coronal, axial and MRCP scans, and the preoperative diagnosis was correct, which was consistent with the intraoperative findings. After the occurrence of internal fistula of hepatic encapsulated worms and intrahepatic bile ducts, the tissue of the inner wall of the encapsulated cysts, cystic fluid and the head nodes within the cystic fluid directly enter the intestines through the biliary system, and through the dissemination and transplantation can increase the chances of generating multiple secondary encapsulated cysts, and the encapsulated worm contents into the intestinal tract can be subject to allergic reactions and other conditions, and through the defecation of the patient after such patients to become a new source of infection.