Mirizzi syndrome is the development of obstructive jaundice due to a large gallstone in the cystic duct or gallbladder neck (Hartmann's pouch) extrinsically compressing the common hepatic duct (CHD). It is a rare complication of cholecystitis (0.7-1.4% of cholecystectomy cases) and is surgically important due to high risk of bile duct injury. Classified by Csendes/McSherry classification: Type I (extrinsic compression, no fistula), Type II-IV (cholecystocholedochal fistula — stone erosion into CHD, increasing fistula size). Chronic inflammation and stone impaction can lead to stricture and chronic obstruction of the common hepatic duct.
Age Range
40-80
Peak Age
60
Gender
Female predominant
Prevalence
Rare
In Mirizzi syndrome, a large gallstone becomes impacted in the cystic duct or Hartmann's pouch. Anatomic variations (long cystic duct, parallel course of cystic duct to CHD, low cystic duct insertion) predispose to this condition. Mechanical compression by the stone narrows the CHD causing obstructive jaundice (Type I). Chronic pressure necrosis and inflammation lead to fistula formation between gallbladder and CHD — stone erodes into CHD lumen (Type II-IV). As fistula size increases, CHD wall defect widens. Chronic inflammation creates pericholecystic fibrosis and adhesions distorting anatomy during surgery and increasing bile duct injury risk. In imaging, this reflects as impacted stone at cystic duct/Hartmann's pouch level, proximal intrahepatic bile duct dilatation, normal caliber distal CBD, and pericholecystic inflammatory changes.
MRCP shows hypointense impacted stone at cystic duct or Hartmann's pouch level extrinsically compressing and narrowing the common hepatic duct. Proximal intrahepatic bile ducts are dilated, distal CBD is normal caliber. This pattern is pathognomonic for Mirizzi syndrome.
MRCP shows hypointense filling defect (impacted stone) at cystic duct/Hartmann's pouch level with extrinsic compression narrowing the CHD. Dilated intrahepatic ducts above (proximal) and normal-caliber CBD below (distal) the stone. In Type II-IV, protrusion of stone into CHD lumen and fistula may be visible. MRCP is the gold standard for preoperative evaluation as it non-invasively demonstrates biliary anatomy, stone position, and fistula presence.
Report Sentence
MRCP demonstrates an impacted stone at the cystic duct/Hartmann's pouch level extrinsically compressing the common hepatic duct with resultant proximal intrahepatic bile duct dilatation; consistent with Mirizzi syndrome.
Hyperdense stone at gallbladder neck/cystic duct level with narrowed CHD segment adjacent to the stone on portal venous phase. Proximally dilated intrahepatic ducts, normal CBD distally. Pericholecystic fluid and increased fat density (inflammation). Gallbladder wall thickened and enhancing (chronic cholecystitis). In Type II-IV, stone may be seen in CHD lumen.
Report Sentence
Impacted stone at gallbladder neck/cystic duct level extrinsically compresses the common hepatic duct with proximal biliary dilatation; consistent with Mirizzi syndrome.
Echogenic stone in gallbladder neck or cystic duct (with posterior acoustic shadowing) and narrowed CHD adjacent to stone on US. Proximal intrahepatic bile duct dilatation (>2 mm). Gallbladder wall thickened (>3 mm). Murphy's sign may be positive. US is often the first diagnostic method but preoperative diagnosis of Mirizzi syndrome is difficult — MRCP confirmation is recommended.
Report Sentence
Echogenic stone with posterior shadowing is seen at gallbladder neck level with proximal intrahepatic bile duct dilatation; should be evaluated for Mirizzi syndrome.
Hyperdense stone at gallbladder neck/cystic duct level on non-contrast CT (usually >10 mm). Stone position close to CHD and proximal biliary dilatation suggest Mirizzi syndrome. Non-contrast CT is most sensitive for stone detection but contrast-enhanced CT/MRI is needed for soft tissue detail and fistula evaluation.
Report Sentence
Hyperdense impacted stone at gallbladder neck level is seen on non-contrast CT with proximal biliary dilatation; suggestive of Mirizzi syndrome.
Communication with fluid signal between gallbladder and CHD on T2-weighted images — cholecystocholedochal fistula (Type II-IV). Fistula tract is seen filled with hyperintense fluid. Stone appears as hypointense filling defect within fistula or CHD lumen. Determining fistula size changes the surgical approach.
Report Sentence
Fistula between gallbladder and common hepatic duct is seen on T2-weighted series with hypointense stone in the duct lumen; consistent with Mirizzi syndrome Type II.
Inflammatory changes around gallbladder on arterial phase — pericholecystic fluid, increased fat density (stranding), gallbladder wall enhancement. Inflammatory thickening and enhancement at hepatoduodenal ligament level reflects the chronic process in Mirizzi syndrome. These findings help predict the degree of adhesion and fibrosis encountered during surgery.
Report Sentence
Pericholecystic fluid, fat stranding, and wall enhancement are seen around the gallbladder; inflammatory changes consistent with chronic cholecystitis/Mirizzi syndrome.
Criteria
Stone in cystic duct/Hartmann's pouch extrinsically compresses CHD, no fistula formed. CHD wall integrity is preserved. Treated with standard laparoscopic/open cholecystectomy.
Distinct Features
CHD narrowed but no wall defect on MRCP, no fistula between gallbladder and CHD.
Criteria
Chronic necrosis from stone pressure has created gallbladder-CHD fistula. Fistula involves <1/3 of CHD circumference. Requires cholecystectomy + fistula repair + T-tube or Roux-en-Y hepaticojejunostomy.
Distinct Features
Fistula tract filled with hyperintense fluid between gallbladder and CHD on T2, stone may partially protrude into CHD lumen.
Criteria
Type III: fistula involves 1/3-2/3 of CHD circumference. Type IV: fistula involves >2/3 of CHD circumference or CHD wall is completely destroyed. Roux-en-Y hepaticojejunostomy is mandatory. CHD reconstruction may be needed in Type IV.
Distinct Features
Wide communication on MRCP/T2, most of CHD wall is defective, gallbladder and CHD may have formed almost a single lumen.
Distinguishing Feature
In choledocholithiasis, stone is within CBD lumen creating an intraluminal filling defect. In Mirizzi, stone is in cystic duct/Hartmann's pouch compressing CHD externally — stone is outside the duct lumen (in Type I).
Distinguishing Feature
Hilar cholangiocarcinoma causes irregular wall thickening/mass + stricture in duct wall, no stone. In Mirizzi, impacted stone is clearly visible, duct wall thickening is inflammatory and smooth (unless malignant transformation).
Distinguishing Feature
Benign biliary stricture shows smooth concentric narrowing without stone, usually with surgical/inflammatory history. In Mirizzi, stricture is secondary to stone impaction and the impacted stone is visualized.
Distinguishing Feature
Acute cholangitis shows diffuse bile duct dilatation + wall enhancement, obstructive cause may be stone or stricture. In Mirizzi, specifically impacted stone at cystic duct level extrinsically compresses CHD.
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
specialist-referralMirizzi syndrome is an urgent condition requiring surgical treatment. Preoperative diagnosis is critical because the risk of bile duct injury is very high if not recognized during standard laparoscopic cholecystectomy. Preoperative MRCP evaluation (fistula presence, type determination) guides surgical planning. In Type I, laparoscopic cholecystectomy may be performed but requires experienced surgeon. In Type II-IV, open surgery + Roux-en-Y hepaticojejunostomy is recommended. ERCP may provide biliary decompression with preoperative stent placement. Association with gallbladder carcinoma should be kept in mind due to chronic inflammation.
Preoperative diagnosis of Mirizzi syndrome is important — prevents bile duct injury during standard cholecystectomy. MRCP is preferred for preoperative evaluation. Type I is treated with simple cholecystectomy while Types II-IV require fistula repair and biliary reconstruction.