Pancreaticobiliary maljunctions (PBMs) are congenital anomalies of the junction between pancreatic and bile ducts, frequently associated with bile duct cyst (BDC). BDC is congenital biliary tree diseases that are characterized by distinctive dilatation types of the extra- and/or intrahepatic bile ducts. Todani's types I and IVa, in which dilatation involves principally the main bile duct, are the most frequent. PBM induces pancreatic juice reflux into the biliary tract that is supposed to be one of the main factors of biliary cancer degeneration, although the diagnostic criteria of PBM that can be either morphological and/or functional are not well defined especially in Western series.
The aim of this study was to assess the relative prevalence of PBM in BDC in a large European multicenter study, to analyze the characteristics of PBM and try to propose diagnostic criteria of PBMs based on morphological and/or functional criteria and define the positive, negative predictive values, sensibility and specificity of either criteria.
From 1975 to 2012, 263 patients with BDC were analyzed. Among them, 190 (72.2 %) were considered to present PBM. Types I and IVa had a similar rate of PBM association. According to the "AFC classification," 57.2 % had a C-P type, 34.5 % a P-C type and 8.3 % a complex type ("anse-de-seau"). The median length of the common channel in patients with PBM was 15.8 ± 6.8 mm (range 5-40 mm). The median intrabiliary amylase and lipase levels were 65,249 and 172,104 UI/L, respectively. For the diagnostic of PBM, a common channel length of more than 8 mm and an intrabiliary amylase level superior to 8000 UI/L were associated with a predictive positive value and a specificity of more than 90 %. Synchronous biliary cancer had an incidence of 8.7 % in all patients with BDC and PBM 11.1 % in adults. Compared to type IV, the type I BDC was associated with statistically more cancer patients in the presence of PBM.
Characteristics of PBM associated with BDC in Western population are quite close to reported Eastern series. The results suggest considering both the intrabiliary value of amylase >8000 UI/L and a length of a common channel >8 mm as appropriate values for positive diagnosis of PBM.