Friday 3 September 2010
Pancreaticobiliary maljunction (PBM) is a congenital anomaly defined as a junction of the pancreatic and bile ducts located outside the duodenal wall, usually forming a markedly long common channel.
In PBM patients, this anomaly allows regurgitation between the pancreatobiliary and biliopancreatic tract.
Since hydrostatic pressure within the pancreatic duct is usually higher than that in the common bile duct, pancreatic juice frequently refluxes into the bile duct.
As a result, pancreatic enzyme levels are generally very high in the bile and there is a related high incidence of biliary cancer.
PBM can be divided into PBM with biliary dilatation (congenital choledochal cyst [CCC]) and PBM without biliary dilatation (maximal diameter of the bile duct < or= 10 mm).
Because of the increased cell proliferation with random K-ras mutations, the gallbladder mucosa of PBM patients should be considered premalignant.
Congenital choledochal cyst (CCC) treatment is prophylactic flow-diversion surgery, but only prophylactic cholecystectomy is usually performed for PBM without biliary dilatation.
Pancreatobiliary reflux and premalignant changes in the gallbladder can occur in patients with a relatively long common channel (high confluence of pancreaticobiliary ducts).
Gallbladder and bile duct carcinomas are seen in 21% and 15% of patients with PBM and biliary dilatation, respectively. (20551651)
At diagnosis, patients with gallbladder or bile duct carcinoma associated with PBM were younger than those without PBM (p < 0.01).
Gallstones are detected only in 6% of the patients with PBM-associated gallbladder carcinoma.
Multiple biliary carcinomas were detected in 38% of patients with PBM-associated bile duct carcinoma. (20551651)
Some PBM patients had pancreatic disorders:
acute biliary pancreatitis
In PBM patients, pancreatobiliary reflux frequently leads to biliary cancer, and biliopancreatic reflux often leads to acute or chronic pancreatitis. The biliary tract of PBM patients can be considered premalignant.
Pancreaticobiliary maljunction. Kamisawa T, Takuma K, Anjiki H, Egawa N, Kurata M, Honda G, Tsuruta K, Sasaki T. Clin Gastroenterol Hepatol. 2009 Nov;7(11 Suppl):S84-8. PMID: 19896105