This 58 year old man was referred for evaluation and management of jaundice. His CT scan demonstrated this mass in the region of the cystic duct and Hartman's Pouch in the neck of the gallbladder. No calcifications were seen though cholelithiasis was in the differential.
On injection, contrast fills the CBD up to and around the lesion. A thread of contrast can be seen filling the cystic duct in a pattern similar to the napkin ring appearance of a partially obstructing colon cancer. Cholangioscopy is performed and demonstrates mucosal inflammation, erythema, and bulging in the area of the obstruction. No obvious signs of malignancy such as tumor neovascularization, papillary pattern, or mucosa bleeding are seen. Brushings from the area are taken, but were nondiagnostic. Therefore the patient returned 10 days later for repeat study to obtain more specimens to confirm the diagnosis of malignancy.
At this second ERCP, the cholangiogram appears to have changed. The abnormality now has the appearance of an intraductal filling defect suggestive of a stone at the junction of the cystic duct and the common hepatic duct. Contrast now easily fills the cystic duct. Cholangioscopy immediately identifies the abnormality as a stone. EHL is performed to fragment this large stone permitting duct clearance. Clearly during the intervening 10 days the stone migrated out from the cystic duct where it produced the mass-like effect causing the patient's jaundice.
Cystic duct stone compression of the common hepatic duct producing a malignant like biliary obstruction was first described by Dr. Mirizzi in 1948. A classification of four types of Mirizzi syndrome is reported.
Type 1 is an obstruction of the cystic duct or Hartman's pouch due to a stone compressing the hepatic duct and accounts for over 90% of Mirizzi cases.
Type 2 obstruction is due to a stone that has eroded into the hepatic duct from a cholecystocholedocho fistula and is seen at only 1% of operative cholecystectomies.
Type 3 and type 4 are stenosis at the confluence of the cystic duct and the hepatic duct due to either a stone or cholecystitis respectively.
This second example is of a man who also presented with obstructive jaundice. Notice that the stone is approximately 10 mm whereas the common bile duct is 4-5 mm in diameter. It seems unlikely that a rounded stone of this size could have formed in such a small duct suggesting that the stone originated in the gallbladder then migrated and eroded into the common hepatic duct as with our previous example. These cases raise the possibility that Mirizzi syndrome is a more common source of obstructing common duct stones than previously suspected.
Peter B. Kelsey, M.D., Harvard Medical School, Massachusetts General Hospital