British Journal of Radiology (2005) 78, 655-658
© 2005 British Institute of Radiology
doi: 10.1259/bjr/79860768
Anomalous pancreaticobiliary junction (APBJ) with the drainage of the uncinate process into the minor papilla: demonstration by MRI
M Basaranoglu, MD
1
N C Balci, MD
2 and
H U Klör, MD
3
1 Department of Internal Medicine, Kadir Has University Hospital, Istanbul, 2 Department of Radiology, Kocaeli University Hospital, Kocaeli, Turkey and 3 Medicine Clinic III, Justus-Liebig-Universität Giessen, Giessen, Germany
Correspondence: Metin Basaranoglu, Soganli mah., alper sok., yuvam apt., no: 1/20, Bahcelievler, Istanbul, zip code: 34 590, Turkey
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Abstract
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We report a case of a 30-year-old patient with anomalous pancreaticobiliary junction (APBJ) that has not been described before. The patient had a clinical history of recurrent attacks of pancreatitis, cholangitis and cholecystitis that were confirmed by abnormal laboratory values. Endoscopic retrograde cholangiopancreatography revealed a 20 mm long junction of choledoc and pancreatic duct, and uncinate process draining into the minor papilla. On MR cholangiopancreatography, strictures at the junction of hepatic duct, increased gallbladder wall thickness and intraductal stone in the pancreatic duct were demonstrated as complementary findings. Other MRI findings included decreased signal intensity of the pancreas consistent with fibrosis from past pancreatitis attacks and atrophy of the left liver lobe.
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Introduction
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Anomalies of the pancreaticobiliary junction (APBJ) are the congenital variations of pancreaticobiliary union [1]. Clinically APBJ are uncommonly symptomatic but may present themselves with associated conditions ranging from benign acute abdominal pain to carcinomas [2]. Recent developments in both imaging techniques and endoscopic manipulations together with increasing awareness have improved the clinical diagnosis and management of APBJ with their associated complications [2–4]. In this case report, we describe an adult patient with an APBJ where the duct of the uncinate process drains abnormally into the minor papilla with the coexisting long common channel. Additional associated clinicopathological consequences are also described. To the best of our knowledge, a case with uncinate process draining to the minor papilla has not been previously reported.
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Case report
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A 30-year-old man was admitted to our hospital with abdominal pain, nausea and vomiting lasting for 36 h. In his past medical history, he described four attacks of pancreatitis between 1977 and 1991. In the last reported attack (1991), ultrasound revealed increased gallbladder wall thickness. Hepatobiliary iminodiacetic acid (HIDA) scan and endoscopic retrograde cholangiopancreatography (ERCP) revealed no abnormality. In the current admission, his serum laboratory tests revealed increased levels of pancreatic and liver enzymes with abnormal liver function tests. Ultrasound showed mild dilatation of the intrahepatic ducts and the common bile duct, gallbladder distention, and increased thickness of the gallbladder wall without gallstones. Enlargement of the pancreatic head and body with a decreased echogenicity were also observed. The patient then underwent MRI and MR cholangiopancreatography (MRCP). MRI examination was performed by a 1.5 Tesla scanner (Intera; Philips Medical Systems, Best, The Netherlands) and findings included decreased signal intensity on T1 weighted fat suppressed images and decreased contrast enhancement on arterial phase images of the entire pancreas without intraparenchymal or peripancreatic oedema (Figure 1
). The decreased parenchymal signal intensity and contrast enhancement were interpreted to be the results of fibrosis from past attacks of pancreatitis. Another finding was the atrophy of the left liver lobe. On MRCP, the united portion of the distal common bile duct and pancreatic duct measured 20 mm and the drainage of the uncinate process occurred at the minor papilla (Figure 2). A 2 mm intraductal stone was also depicted at the corpus portion of the pancreatic duct. Further findings on MRCP were as follows: gallbladder distension, stricture at the level of common hepatic duct and multiple strictures in the biliary tree of the left liver lobe. The stricture at the level of common hepatic duct was present in the past ERCP (Figure 3a) but the intraductal stone and intrahepatic biliary strictures were new findings.
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Figure 1. (a) Axial T1 weighted fat suppressed spoiled gradient echo image shows diffusely decreased signal intensity of the pancreas (arrows) before contrast medium and (b) decreased contrast enhancement (arrows). Both findings are consistent with fibrotic chances from passed pancreatitis attacks. (c) Axial T2 weighted image at the level of left liver lobe reveals atrophy of the left liver lobe and curvilinear appearance of the intrahepatic biliary tree in the left liver lobe (small arrows).
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Figure 2. MR cholangiopancreatography reveals a long common channel (long thin arrow), the biliary stricture is marked with a long thick arrow and the uncinate process draining into the minor papilla is marked with small thin arrow. There is an intraductal stone in the dorsal pancreatic duct (thick small arrow).
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Figure 3. (a) Endoscopic retrograde cholangiopancreatography of the patient 13 years ago shows the long common channel (long thin arrow), and the uncinate process draining into the minor papilla (small thick arrow). The benign stricture at the level of hepatic duct bifurcation is also demonstrated (small thin arrow). (b) The abnormalities demonstrated schematically.
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The patient was treated conservatively with supportive care; recovered well and was discharged with normal amylase and normal liver function tests.
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Discussion
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In normal embryological development of the pancreas, dorsal and ventral pancreatic ducts fuse to form the main pancreatic duct. An accessory pancreatic duct remains draining at the minor papilla. A common channel is created in the second part of the duodenum with the union of the common biliary and pancreatic ducts [1]. This channel enters into the major papilla. APBJ results from the failed fusion of dorsal and ventral pancreatic ducts and/or pancreatic duct and common bile duct. APBJs are usually depicted in the paediatric patients during the diagnostic work up of recurrent jaundice and abdominal pain. Unpredictable onset of symptoms and remissions characterize the long-term course of APBJ. However, it is not uncommon for patients with APBJ to present with late complications or incidentally [2].
In one type of APBJ, the pancreatic duct and common bile duct unite outside the wall of the duodenum and form a long common channel [5]. A "long common channel" is defined as one 
ge;15 mm in length. In our patient, the length of the common channel was 20 mm. The junction of the common bile duct and pancreatic duct is crucial for sphincter control of bile and pancreatic juice drainage. Bidirectional regurgitation both into the common bile duct and into the pancreatic duct occurs if the junction is located significantly behind Oddi's sphincter in which case pancreatic juice may enter the common bile duct and vice versa causing proteolytic and inflammatory injury. This may lead to abdominal pain, biliary infections, biliary strictures, cysts and carcinomas. Gallbladder wall thickening without gallstone is an associated finding of APBJ compatible with the acalculous cholecystitis secondary to bile reflux [6]. Bile reflux into the pancreatic duct occurs when a long common channel is blocked by stones, protein plug or due to a dysfunction of the sphincter of Oddi. Then, the resulting transient rise in the intraductal pressure of the pancreatic duct causes the destruction and inflammation of the pancreas. With repeated attacks, pancreatic stone formation, ductal changes, chronic pancreatitis, and even pancreatic carcinoma may occur [2, 7]. In the present case, the evidence of bidirectional reflux is (i) elevated both liver and pancreatic enzymes during the attacks, (ii) biliary and pancreatic changes on imaging during the attacks, and (iii) the presence of biliary strictures and stone formation in the pancreatic duct.
The drainage of the uncinate process is always through the major papilla. The anomalous drainage of the uncinate process into the minor papilla has not been reported. In our case, minor papilla with its smaller opening was overloaded receiving both the accessory channel of the dorsal pancreatic duct and anomalous drainage of the uncinate process (Figure 3b
). This may have aggravated pancreatitis attacks together with the existing reflux secondary to long common channel.
The overall frequency of carcinoma of the biliary tract in patients with APBJ is 14% in patients with choledochal cyst while 50% in those without. Various oncogenic mechanisms have been suggested in patients with APBJ, such as regurgitation of pancreatic juice, cholestasis, biliary infections, and formation of carcinogens in bile [7, 8]. Therefore, an anomalous junction should be diagnosed and aggressively treated before pancreaticobiliary complications or biliary tract carcinomas develop.
The optimum approach for the treatment of APBJ is the prevention of the reflux of bile and pancreatic juice into the bile duct system and the pancreas [9]. Previous studies revealed that endoscopic approaches appeared to eliminate or decrease the frequency of pancreatitis attacks. Minor papilla dilatation endoscopically and prophylactic cholecystectomy because of high risk of gallbladder cancer are recommended procedures in our patient initially.
As no additional risk factors such as cholecystectomy, abdominal trauma, or endoscopic manipulations all of which can cause biliary stricture were noted, we believe that these strictures are due to the reflux into the biliary tract and associated possible cholangitis. Presence of the biliary strictures on the previous ERCP image is evidence of their benign nature.
The occurrence of atrophy of the liver lobe has not been previously reported in patients with APBJ. With no vascular anomaly and cirrhosis features, repeated biliary infections and bile duct strictures are the most likely cause of atrophy of the left liver lobe in this case.
APBJ should be considered in the differential diagnosis, when patients present with recurrent pancreatitis with biliary abnormalities. MRCP and ERCP can both allow early diagnosis and may help prevent associated complications.
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Acknowledgments
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The authors offer thanks to Stephen H Caldwell, MD for comments (University of Virginia, Virginia Health Center, Gastroenterology and Hepatology Department).
Received for publication September 23, 2004.
Revision received February 16, 2005.
Accepted for publication February 24, 2005.
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References
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Abstract
Introduction
