Utility of Contrast-Enhanced Harmonic Endoscopic Ultrasonography to Diagnose Pancreaticobiliary Maljunction.

BACKGROUND: Detection of a common channel outside the duodenal wall is important in diagnosing pancreaticobiliary maljunction (PBM). The present study evaluated the utility of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) in diagnosing PBM. METHODS: This single-center retrospective study enrolled 45 patients who were diagnosed with PBM or high confluence of pancreatobiliary ducts (HCPBD) between January 2007 and December 2021. The diagnostic sensitivities of contrast-enhanced computed tomography (CE-CT), magnetic resonance imaging (MRI), and CH-EUS for diagnosing PBM were analyzed. Imaging findings were evaluated by two reviewers blinded to the clinicopathological results. RESULTS: Based on diagnostic criteria, 33 patients were diagnosed with PBM and 12 with HCPBD. Compared with the patients with HCPBD, those with PBM had significantly longer common channel (12.5 mm vs. 8.1 mm, P = 0.018) and common bile duct (13.0 mm vs. 8.6 mm, P = 0.049) lengths. The κ-coefficients for differentiating PBM and HCPBD were 0.871 between CE-CT and MRI, 0.330 between CE-CT and CH-EUS, and 0.611 between MRI and CH-EUS. The diagnostic sensitivity of CH-EUS (95.2%) was higher than that of CE-CT (83.3%) and MRI (82.8%), although the differences were not statistically significant. CONCLUSION: CH-EUS may be useful for the diagnosis of PBM.

A case report of carcinoma of the papilla of Vater associated with a hyperplasia-dysplasia-carcinoma sequence by pancreaticobiliary maljunction.

BACKGROUND: Pancreaticobiliary maljunction (PBM) is a known risk factor for biliary tract cancer. However, its association with carcinoma of the papilla of Vater (PVca) remains unknown. We report a case with PVca that was thought to be caused by the hyperplasia-dysplasia-carcinoma sequence, which is considered a mechanism underlying PBM-induced biliary tract cancer. CASE PRESENTATION: A 70-year-old woman presented with white stool and had a history of cholecystectomy for the diagnosis of a non-dilated biliary tract with PBM. Esophagogastroduodenoscopy revealed a tumor in the papilla of Vater, and PVca was histologically proven by biopsy. We finally diagnosed her with PVca concurrent with non-biliary dilated PBM (cT1aN0M0, cStage IA, according to the Union for International Cancer Control, 8th edition), and subsequently performed subtotal stomach-preserving pancreaticoduodenectomy. Pathological findings of the resected specimen revealed no adenomas and dysplastic and hyperplastic mucosae in the common channel slightly upstream of the main tumor, suggesting a PBM related carcinogenic pathway with hyperplasia-dysplasia-carcinoma sequence. Immunostaining revealed positivity for CEA. CK7 positivity, CK20 negativity, and MUC2 negativity indicated that this PVca was of the pancreatobiliary type. Genetic mutations were exclusively detected in tumors and not in normal tissues, and bile ducts from formalin-fixed paraffin-embedded samples included mutated-ERBB2 (Mutant allele frequency, 81.95%). Moreover, of the cell-free deoxyribonucleic acid (cfDNA) extracted from liquid biopsy mutated-ERBB2 was considered the circulating-tumor deoxyribonucleic acid (ctDNA) of this tumor. CONCLUSIONS: Herein, we report the first case of PVca with PBM potentially caused by a "hyperplasia-dysplasia-carcinoma sequence" detected using immunostaining and next-generation sequencing. Careful follow-up is required if pancreaticobiliary reflux persists, considering the possible development of PVca.

Morphological changes in the biliary mucosa in pediatric patients with congenital biliary dilatation are more influenced by the duration of amylase exposure than by amylase levels in the gallbladder.

PURPOSE: We investigated the relationship between bile amylase (AMY) levels and biliary epithelial changes in pancreaticobiliary maljunction (PBM), a congenital anomaly characterized by pancreaticobiliary reflux due to duct fusion outside the duodenal wall. METHODS: We enrolled 43 children with congenital biliary dilatation (CBD) of Todani types Ia, Ic, and IVa who underwent surgery at the Hokkaido Medical Center for Child Health and Rehabilitation between November 2007 and June 2023. We defined total AMY exposure in bile as bile AMY levels multiplied by the patient's age (months), representing amount of estimated AMY exposure until surgery. We retrospectively investigated the relationships between bile AMY levels and clinicopathological findings. RESULTS: All patients exhibited hyperplasia in the gallbladder and bile duct epithelium, with dysplasia observed in 13 cases, but no carcinoma. Exposure to bile AMY ≥ 662,400 IU/L × months was an independent risk factor for dysplasia. CONCLUSION: The amount of estimated AMY exposure in bile rather than AMY levels in the bile is an independent risk factor for dysplasia in the biliary mucosa.

[Gallbladder carcinosarcoma associated with pancreaticobiliary maljunction with biliary dilation:a case report].

A 68-year-old female patient was referred to our hospital with acute cholangitis. Computed tomography revealed common bile duct dilatation, gallbladder fundal tumor, and gallbladder wall thickening attached to the tumor. Cholangiography revealed pancreaticobiliary maljunction with biliary dilation. The patient was diagnosed with pancreaticobiliary maljunction with biliary dilation and gallbladder cancer and underwent liver S4b+5 and bile duct resection and reconstruction. Pathological results revealed that the gallbladder fundal tumor included sarcoma, and the gallbladder wall thickening had adenocarcinoma;thus, the patient was diagnosed with gallbladder carcinosarcoma.

[Double extrahepatic bile duct with pancreaticobiliary maljunction:a case report].

A 76-year-old woman with a suspected double extrahepatic bile duct was referred to our hospital. MRCP revealed that the left hepatic and posterior ducts combined to form the ventral bile duct and that the anterior duct formed the dorsal bile duct. ERCP demonstrated that the ventral bile duct was linked with the Wirsung duct. Amylase levels in the bile were unusually high. Based on these findings, we diagnosed a double extrahepatic bile duct with pancreaticobiliary maljunction and choledocholithiasis. Duplicate bile duct resection and bile duct jejunal anastomosis were performed considering the risk of biliary cancer due to pancreaticobiliary maljunction. The resected bile duct epithelium demonstrated no atypia or hyperplastic changes.

Development of an MRI-Based Radiomics-Clinical Model to Diagnose Liver Fibrosis Secondary to Pancreaticobiliary Maljunction in Children.

BACKGROUND: Preoperative diagnosis of liver fibrosis in children with pancreaticobiliary maljunction (PBM) is needed to guide clinical decision-making and improve patient prognosis. PURPOSE: To develop and validate an MR-based radiomics-clinical nomogram for identifying liver fibrosis in children with PBM. STUDY TYPE: Retrospective. POPULATION: A total of 136 patients with PBM from two centers (center A: 111 patients; center B: 25 patients). Cases from center A were randomly divided into training (74 patients) and internal validation (37 patients) sets. Cases from center B were assigned to the external validation set. Liver fibrosis was determined by histopathological examination. FIELD STRENGTH/SEQUENCE: A 3.0 T (two vendors)/T1-weighted imaging and T2-weighted imaging. ASSESSMENT: Clinical factors associated with liver fibrosis were evaluated. A total of 3562 radiomics features were extracted from segmented liver parenchyma. Maximum relevance minimum redundancy and least absolute shrinkage and selection operator were recruited to screen radiomics features. Based on the selected variables, multivariate logistic regression was used to construct the clinical model, radiomics model, and combined model. The combined model was visualized as a nomogram to show the impact of the radiomics signature and key clinical factors on the individual risk of developing liver fibrosis. STATISTICAL TESTS: Mann-Whitney U and chi-squared tests were used to compare clinical factors. P < 0.05 was considered statistically significant in the final models. RESULTS: Two clinical factors and four radiomics features were selected as they were associated with liver fibrosis in the training (AUC, 0.723, 0.927), internal validation (AUC, 0.718, 0.885), and external validation (AUC, 0.737, 0.865) sets. The radiomics-clinical nomogram yielded the best performance in the training (AUC, 0.977), internal validation (AUC, 0.921), and external validation (AUC, 0.878) sets, with good calibration (P > 0.05). DATA CONCLUSION: Our radiomic-based nomogram is a noninvasive, accurate, and preoperative diagnostic tool that is able to detect liver fibrosis in PBM children. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.

Clinical presentations and outcomes of pancreaticobiliary maljunction in different pediatric age groups.

BACKGROUND: Pancreaticobiliary maljunction (PBM) is a congenital defect, with risk of developing various pancreaticobiliary and hepatic complications. The presentations of PBM in children and adults are believed to be different, but studies on PBM children of different age groups are limited. This study was to evaluate clinicopathologic characteristics and outcomes in PBM children of different ages. METHODS: A total of 166 pediatric patients with PBM were reviewed retrospectively. Clinicopathological, imaging, laboratory, surgical, and follow-up data were collected and analyzed. The patients were divided into three age groups, namely, group A (< 1 year, n = 31), group B (1-3 years, n = 63), and group C (> 3 years, n = 72). RESULTS: The major clinical manifestation was jaundice in group A and abdominal pain and vomiting in groups B and C. Acute pancreatitis was more often seen in group C than group A. The length of common channel was significantly longer in group C than group A, while the maximum diameter of common bile duct in group C was smaller than that in group A. Cholangitis and cholecystitis were more commonly performed in groups B and C, while hepatic fibrosis in group A. Whether preoperatively or postoperatively, group C was more likely to have elevated serum amylase, while groups A and B were more likely to present with abnormal liver function indicators, including the increase of aspartate transaminase, alanine transaminase, and gamma-glutamyl transpeptidase. CONCLUSION: Presentation of PBM varies among different pediatric age groups, thus suggesting that targeted management should be carried out according to these differences.

Using machine learning models to predict acute pancreatitis in children with pancreaticobiliary maljunction.

PURPOSE: To develop a model to identify risk factors and predictors of acute pancreatitis in children with pancreaticobiliary maljunction (PBM). METHODS: We screened consecutive PBM patients treated at two centers between January, 2015 and July, 2021. For machine learning, the cohort was divided randomly at a 6:4 ratio to a training dataset and a validation dataset. Three parallel models were developed using logistic regression (LR), a support vector machine (SVM), and extreme gradient boosting (XGBoost), respectively. Model performance was judged primarily based on the area under the receiver operating curves (AUC). RESULTS: A total of 99 patients were included in the analysis, 17 of whom suffered acute pancreatitis and 82 did not. The XGBoost (AUC = 0.814) and SVM (AUC = 0.813) models produced similar performance in the validation dataset; both outperformed the LR model (AUC = 0.805). Based on the SHapley Additive exPlanation values, the most important variable in both the XGBoost and SVM models were age, protein plugs, and white blood cell count. CONCLUSIONS: Machine learning models, especially XGBoost and SVM, could be used to predict acute pancreatitis in children with PBM. The most important contributing factor to the models were age, protein plugs, and white blood cell count.

Using machine learning models to predict the surgical risk of children with pancreaticobiliary maljunction and biliary dilatation.

PURPOSE: To develop machine learning (ML) models to predict the surgical risk of children with pancreaticobiliary maljunction (PBM) and biliary dilatation. METHODS: The subjects of this study were 157 pediatric patients who underwent surgery for PBM with biliary dilatation between January, 2015 and August, 2022. Using preoperative data, four ML models were developed, including logistic regression (LR), random forest (RF), support vector machine classifier (SVC), and extreme gradient boosting (XGBoost). The performance of each model was assessed via the area under the receiver operator characteristic curve (AUC). Model interpretations were generated by Shapley Additive Explanations. A nomogram was used to validate the best-performing model. RESULTS: Sixty-eight patients (43.3%) were classified as the high-risk surgery group. The XGBoost model (AUC = 0.822) outperformed the LR (AUC = 0.798), RF (AUC = 0.802) and SVC (AUC = 0.804) models. In all four models, enhancement of the choledochal cystic wall and an abnormal position of the right hepatic artery were the two most important features. Moreover, the diameter of the choledochal cyst, bile duct variation, and serum amylase were selected as key predictive factors by all four models. CONCLUSIONS: Using preoperative data, the ML models, especially XGBoost, have the potential to predict the surgical risk of children with PBM and biliary dilatation. The nomogram may provide surgeons early warning to avoid intraoperative iatrogenic injury.

Prediction of post-operative acute pancreatitis in children with pancreaticobiliary maljunction using machine learning model.

PURPOSE: This study aimed to develop a prediction model to identify risk factors for post-operative acute pancreatitis (POAP) in children with pancreaticobiliary maljunction (PBM) by pre-operative analysis of patient variables. METHODS: Logistic regression (LR), support vector machine (SVM), and extreme gradient boosting (XGBoost) models were established using the prospectively collected databases of patients with PBM undergoing surgery which was reviewed in the period comprised between August 2015 and August 2022, at the Children's Hospital of Soochow University. Primarily, the area beneath the receiver-operating curves (AUC), accuracy, sensitivity, and specificity were used to evaluate the model performance. The model was finally validated using the nomogram and clinical impact curve. RESULTS: In total, 111 children with PBM met the inclusion criteria, and 21 children suffered POAP. In the validation dataset, LR models showed the highest performance. The risk nomogram and clinical effect curve demonstrated that the LR model was highly predictive. CONCLUSION: The prediction model based on the LR with a nomogram could be used to predict the risk of POAP in patients with PBM. Protein plugs, age, white blood cell count, and common bile duct diameter were the most relevant contributing factors to the models.

Pancreaticobiliary maljunction induced cholangiocarcinoma after gallbladder cancer.

The essence of PBM is the premature confluence of bile duct and pancreatic duct, the mixture of bile and pancreatic juice leads to bile duct cyst, gallstone, gallbladder carcinoma, acute and chronic pancreatitis, etc, and the diagnostic mainly depends on imaging, anatomical examination and bile hyperamylase.

Pancreaticobiliary maljunction in Turkish patients: a multicenter case series.

BACKGROUND AND AIMS: Pancreaticobiliary maljunction (PBM) is a malformation in which the pancreatic and bile ducts join outside the duodenal wall. It is associated with various biliary and pancreatic diseases. In addition, patients with PBM carry a substantial lifetime risk of developing biliary or gallbladder carcinoma. We aimed to present a multicenter case series of PBM from Turkey. METHODS: This study was conducted in adult and pediatric PBM patients who were referred to three tertiary reference centers of Turkey for endoscopic retrograde cholangiopancreatography (ERCP) between July 2007 and May 2020. The clinical presentations, types of PBM, ERCP findings, surgical histories, and the postoperative courses, including the development of biliary malignancies, were retrospectively reviewed. RESULTS: The study group included 47 (31 adult and 16 children) patients. Type D PBM was more frequent (13/41: 27.7%) than that reported in Eastern studies. Type A PBM was more common in the adults (51.6% vs. 12.5%, p < 0.05), whereas type C was more common in pediatric patients (31.3% vs. 13.2%, p < 0.05). Although fusiform anatomy was predominant in both of the groups, cystic dilatation was more common (25.8% vs. 12.5%) in adults and the common bile duct diameter was greater [22 mm (range 11-58) vs. 12 mm (range 5-33)] in adult patients compared to pediatric patients. Resective surgeries were more frequently done in pediatric patients (73.3% vs. 53.6%), whereas cholecystectomy was more frequently performed in adult patients (21.4% vs. 6.7%). CONCLUSION: Although our findings were compatible with Eastern studies, type D PBM (associated with pancreas divisum) was more frequent in our study population.

Pancreaticobiliary maljunction and pancreas divisum accompanied with intestinal malrotation: a case report.

BACKGROUND: Pancreaticobiliary maljunction is a congenital anatomical abnorma l junction of the pancreatic duct and bile duct into a common channel outside the duodenal wall. Pancreas divisum is also a congenital anatomical abnormality characterized by unfused pancreatic ducts. Intestinal malrotation is caused by the failure of bowel rotation and fixation. We reported an optimal surgical intervention for the rare case of pancreaticobiliary maljunction and pancreas divisum accompanied intestinal malrotation. CASE PRESENTATION: A 2-year-old female presented with fever and jaundice. Abdominal ultrasound showed dilated common bile duct and intrahepatic bile ducts; MRCP showed pancreaticobiliary maljunction, pancreas divisum, and dilated biliary system; Abdominal contrast-enhanced CT showed a reversed relationship between the superior mesenteric artery and the superior mesenteric vein. An operation of laparoscopic resection of the extrahepatic bile duct, Roux-en-Y hepaticojejunostomy, and Ladd's procedure was performed after the inflammation of the biliary system was treated. The post-operative follow-up period was uneventful. CONCLUSIONS: The management of pancreas divisum can be conservative. We present an optimal pattern of Roux-en-Y hepaticojejunostomy to deal with pancreaticobiliary maljunction associated with intestinal malrotation.

Pancreaticobiliary maljunction without biliary dilatation in pediatric patients.

PURPOSE: Pancreaticobiliary maljunction (PBM) without biliary dilatation is a condition in which dilatation of the bile duct is not seen in patients with PBM. Recently, the Japanese Study Group on Pancreaticobiliary Maljunction (JSGPM) published new diagnostic criteria for PBM. In these criteria, biliary dilatation is defined according to the standard diameter at each age. We reviewed cases of pediatric patients with PBM without biliary dilatation. METHODS: From 1992 to 2019, 134 patients with PBM were treated in our institution. Among these, 7 patients were retrospectively diagnosed with PBM without biliary dilatation. The clinical information was retrospectively assessed in these patients. RESULTS: Of the seven patients, six were female. All patients had symptoms similar to those of patients with congenital biliary dilatation. In all seven patients, the diagnosis of PBM was made before definitive surgery. Six patients had type B PBM, and one had type D PBM. All patients underwent extrahepatic bile duct resection and hepaticojejunostomy, and their symptoms resolved. One patient experienced postoperative complications of anastomotic leakage followed by anastomotic stricture. CONCLUSION: The present report revealed important clinical features of this entity. However, there are still some issues that need to be discussed, and further research is needed.

Novel analysis using magnetic resonance cholangiography for patients with pancreaticobiliary maljunction.

PURPOSE: We used a novel diagnostic Fourier transform (FT) algorithm of the entire extrahepatic bile duct (EHBD) measured by magnetic resonance cholangiography (MRC) to evaluate subtle deformation of bile duct lumen, indicating the malignant potential of EHBD, in patients with pancreaticobiliary maljunction (PBMJ) and in a comparative group of controls without PBMJ. METHODS: From the workstation, the EHBD lumen was traced automatically and a 2D diagram cross section was measured at 0.5 mm-longitudinal intervals. The FT-based integrated power spectral density function value (FTPSDI) of the diameter or area (mm2 or mm4/Hz) and the phase value distribution entropy (PVDE) were also measured. RESULTS: There were 16 patients with undilated PBMJ and 7 with dilated PBMJ. The control group comprised 10 patients with a normal bile duct, 20 with bile duct carcinoma (BDC), and 1 with primary sclerosing cholangitis. Both the diameter and area of the dilated bile ducts and the ducts with early- or advanced-stage BDC were significantly greater than those of the normal duct (p < 0.05). The undilated type of PBMJ tended to have a larger FTPSDI diameter than a normal bile duct, which had a smaller diameter than the dilated type of PBMJ or BDC. BDC had a significantly larger FTPSDI diameter (p < 0.05) and the cutoff value for accuracy was 168 mm2 Hz-1. CONCLUSION: The novel mathematical FTPSDI is a promising indicator of whether preventive EHBD resection is necessary for patients with PBMJ, which can be widely applied in the early diagnosis of other biliary diseases.

Risk of carcinogenesis in the biliary epithelium of children with congenital biliary dilatation through epigenetic and genetic regulation.

PURPOSES: Congenital biliary dilatation (CBD), defined as pancreaticobiliary maljunction (PBM) with biliary dilatation, is a high risk factor for biliary tract cancer (BTC). KRAS and p53 mutations reportedly affect this process, but the mechanisms are unclear, as is the likelihood of BTC later in life in children with CBD. We investigated potential carcinogenetic pathways in children with CBD compared with adults. METHODS: The subjects of this study were nine children with CBD and 13 adults with PBM (10 dilated, 3 non-dilated) without BTC who underwent extrahepatic bile duct resections, as well as four control patients who underwent pancreaticoduodenectomy for non-biliary cancer. We evaluated expressions of Ki-67, KRAS, p53, histone deacetylase (HDAC) and activation-induced cytidine deaminase (AID) in the biliary tract epithelium immunohistochemically. RESULTS: The Ki-67 labeling index (LI) and expressions of KRAS, p53, HDAC, and AID in the gallbladder epithelium were significantly higher or tended to be higher in both the children with CBD and the adults with PBM than in the controls. CONCLUSIONS: BTC may develop later in children with CBD and in adults with PBM, via HDAC and AID expression and through epigenetic and genetic regulation.

Stepwise correlation of TP53 mutations from pancreaticobiliary maljunction to gallbladder carcinoma: a retrospective study.

BACKGROUND: The genetic changes underlying carcinogenesis in patients with risk factors of gallbladder carcinoma (GBC) remains controversial, especially in patients with pancreaticobiliary maljunction (PBM). This study aimed to clarify the association between risk factors of GBC and genetic changes using next-generation sequencing (NGS). METHODS: We retrospectively analyzed resected tissues of 64 patients who were diagnosed with GBC (n = 26), PBM [with GBC (n = 8), without GBC (n = 20)], and chronic cholecystitis, used as a control group (n = 10). DNA was extracted from tumors and their surrounding tissues, which were precisely separated by laser-capture microdissection. Gene alterations of 50 cancer-related genes were detected by NGS and compared with clinical information, including PBM status. RESULTS: The most frequent gene alterations in GBC tissues occurred in TP53 (50%), followed by EGFR (20.6%), RB1 (17.6%), and ERBB2 (17.6%). Gene alterations that were targetable by molecular targeted drugs were detected in 20 cases (58.8%). Statistical analysis of gene alterations and risk factors revealed that TP53 alteration rate was higher in GBC patients with PBM than those without PBM (p = 0.038), and the TP53 mutation rates in the epithelium of control patients, epithelium of PBM patients without GBC, peritumoral mucosa of GBC patients with PBM, and tumor tissue of GBC patients with PBM were 10, 10, 38, and 75%, respectively (p <  0.01). CONCLUSIONS: TP53 alteration more than KRAS mutation was revealed to underlie carcinogenesis in patients with PBM.

Preoperative one-stop magnetic resonance imaging evaluation of the pancreaticobiliary junction and hepatic arteries in children with pancreaticobiliary maljunction: a prospective cohort study.

PURPOSE: Pancreaticobiliary maljunction (PBM) is routinely assessed by intraoperative cholangiography (IOC), whereas accompanying abnormalities in the hepatic artery are assessed by preoperative contrast multi-slice computed tomography (MSCT). We evaluated the efficiency of performing one-stop preoperative magnetic resonance imaging (MRI) for delineating the anatomy of the pancreaticobiliary junction and the hepatic artery. METHODS: The subjects of this prospective analysis were children who underwent Roux-en-Y surgery for PBM in our institution during a recent 3-year period. Preoperative one-stop MRI was conducted using 3.0-T MRI. The efficiency of one-stop MRI was compared with that of IOC for assessing the bile duct, and with contrast MSCT for assessing the blood vessels. RESULTS: Sixty-five children underwent one-stop preoperative MRI, which had a 100% concordance rate, versus IOC for assessing the bile duct type. Protein plugs or cholelithiasis were identified by IOC in 8 children and by one-stop MRI in 45 children (P = 0.0233). Cholangitis was not identified by IOC in any children but it was identified by one-stop MRI in 29 children. MSCT was also performed in 46 children and revealed a variant hepatic artery in 9 and cholangitis in 21. One-stop MRI had a 100% concordance rate versus MSCT. CONCLUSION: Preoperative one-stop MRI accurately delineates the bile duct anatomy as well as the hepatic artery, cholangitis, and protein plugs in children with PBM.

[A case of simultaneous multicentric cancer in the gallbladder duct and the common bile duct without pancreaticobiliary maljunction].

A 68-year-old man who underwent cholecystectomy for acute cholecystitis and was diagnosed with gallbladder duct carcinoma was referred to our hospital. Postoperative computed tomography showed thickening of the middle to lower bile duct without any tumorous lesions. Endoscopic retrograde cholangiopancreatography and intraductal ultrasonography revealed irregular wall thickening of the lower bile duct and apparent infiltration of gallbladder duct tumor to the common bile duct without pancreaticobiliary maljunction. Subtotal stomach-preserving pancreaticoduodenectomy was performed. Pathological examination showed papillary adenocarcinoma and tubular adenocarcinoma in the gallbladder duct and BilIN-3 lesion in the distal bile duct. The final diagnosis was biliary simultaneous multicentric cancer without pancreaticobiliary maljunction.

Imaging of Pancreaticobiliary Maljunction.

Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and bile ducts join outside the duodenal wall, usually forming a long common channel. A major issue in patients with PBM is the risk of biliary cancer. Because the sphincter of Oddi does not regulate the pancreaticobiliary junction in PBM, pancreatic juice frequently refluxes into the biliary tract and can cause various complications, including biliary cancer. Most cancers arise in the gallbladder or dilated common bile duct, suggesting that bile stasis is related to carcinogenesis. Early diagnosis and prophylactic surgery to reduce the risk of cancer are beneficial. The diagnosis of PBM is made mainly on the basis of imaging findings. The development of diagnostic imaging modalities such as multidetector CT and MR cholangiopancreatography has provided radiologists with an important role in diagnosis of PBM and its complications. Radiologists should be aware of PBM despite the fact that it is rare in non-Asian populations. In this review, the authors present an overview of PBM with emphasis on diagnosis and management of PBM and its complications. For early diagnosis, the presence of extrahepatic bile duct dilatation or gallbladder wall thickening may provide a clue to PBM with or without biliary dilatation, respectively. The pancreaticobiliary anatomy should be closely examined if imaging reveals these findings. Radiologists should also carefully evaluate follow-up images in PBM patients even years after prophylactic surgery because residual bile ducts remain at risk for cancer.©RSNA, 2020.