Management of Anomalous Pancreaticobiliary Union

We read with interest the letter from Çiçek et al. [1] about a case of anomalous pancreaticobiliary union (APBU) accompanied by congenital choledochal cyst. Because the patient had never experienced an attack of cholangitis or pancreatitis, they followed up the patient without any further treatment. We believe that their management of APBU accompanied by congenital choledochal cyst was inadequate.

APBU is a congenital anomaly defined as a union of the pancreatic and bile ducts that occurs outside the duodenal wall and beyond the influence of the sphincter of Oddi [2] [3] [4] [5]. Among APBU patients, some have cystic, fusiform, or cylindrical dilatation of the bile duct (dilated type; choledochal cyst), whereas others have no dilatation (undilated type) [6]. As evidence of the higher excretory pressure of the pancreas, influx of pancreatic juice into the biliary tract, with high amylase levels, has been found in gallbladder and choledochal cyst aspirates [2]. The incidence of malignant change of the gallbladder and bile duct is notably high in APBU patients, compared with that in the general population [2] [4] [5] [6] [7]. Carcinomas tend to occur where the bile contains amylase stagnates, as seen when gallbladder carcinoma develops in the undilated type and bile duct carcinoma in the dilated type [4] [5] [6] [8] [9].

The reflux of pancreatic juice into the gallbladder may cause increased bile pressure, and result in epithelial hyperplasia [8], one of the characteristic pathological changes in APBU patients [6] [8] [9]. Epithelial hyperplasia is significantly and frequently associated with the undilated type of APBU compared with the dilated type [6]. The expanded population of proliferating cells demonstrated in epithelial hyperplasia appears to predispose the mucosa to DNA damage and mutations such as the K-ras oncogene, ultimately resulting in neoplastic transformation [6]. Because epithelial hyperplasia in APBU patients may exist at birth or be acquired in childhood, increasing in degree thereafter, these findings are in reasonably good agreement with many reports that the risk of carcinoma increased with age among ABPU patients [6].

Because the risk for malignant degeneration increases with the age of APBU patients, and because carcinomas are usually detected at an advanced stage, prophylactic cholecystectomy is recommended for APBU patients with the undilated type [5] [6], and cholecystectomy with excision of the dilated bile duct for those with the dilated-type condition [10]. We therefore believe that the patient of Çiçek et al., who has APBU accompanied by congenital choledochal cyst, should undergo resection of the gallbladder and choledochal cyst.

References

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• 2 Guelrud M, Morera C, Rodriguez M . et al . Sphincter of Oddi dysfunction in children with recurrent pancreatitis and anomalous pancreaticobiliary union: an etiologic concept.  Gastrointest Endosc. 1999;  50 194-199
• 3 Guelrud M, Morera C, Rodriguez M . et al . Normal and anomalous pancreaticobiliary union in children and adolescents.  Gastrointest Endosc. 1999;  50 189-193
• 4 Ohtsuka T, Inoue K, Ohuchida J . et al . Carcinoma arising in choledochocele.  Endoscopy. 2001;  33 614-619
• 5 Yamauchi S, Koga A, Matsumoto S . et al . Anomalous junction of pancreaticobiliary duct without congenital choledochal cyst: a possible risk factor for gallbladder cancer.  Am J Gastroenterol. 1987;  82 20-24
• 6 Tanno S, Obara T, Fujii T . et al . Proliferative potential and K-ras mutation in epithelial hyperplasia of the gallbladder in patients with anomalous pancreaticobiliary ductal union.  Cancer. 1998;  83 267-275
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• 8 Tokiwa K, Iwai N. Early mucosal changes of the gallbladder in patients with anomalous arrangement of the pancreaticobiliary duct.  Gastroenterology. 1996;  110 1614-1618
• 9 Hanada K, Itoh M, Fujii K . et al . Pathology and cellular kinetics of gallbladder with an anomalous junction of the pancreaticobiliary duct.  Am J Gastroenterol. 1996;  9 1007-1011
• 10 Hsu R K, Yu A, Lee J  G. et al . Pancreatitis caused by common bile duct stones in a 3-year-old boy with prior surgery for a choledochal cyst.  Am J Gastroenterol. 2001;  96 1919-1921