Congenital variants and anomalies of the pancreas and pancreatic duct: imaging by magnetic resonance cholangiopancreaticography and multidetector computed tomography

Pancreatic neuroendocrine tumour resection in circumportal pancreas: a rare anatomical anomaly with important surgical implications

Various congenital anomalies of the pancreas have been reported due to its complex embryological development involving the fusion of two separate buds. Circumportal pancreas is a rare anatomical anomaly where the pancreatic head and uncinate process fuse abnormally with the pancreatic body, encasing the portal vein and/or superior mesenteric vein completely. This anomaly poses several challenges to hepatobiliary surgeons, as the encasement of the portal vein by the abnormal pancreatic tissue makes an additional parenchymal transection necessary. Vascular variants have also been reported with circumportal pancreas, which, if not recognised preoperatively, can be catastrophic. Therefore, careful preoperative evaluation and planning are essential, to ensure safe pancreatic resection and recovery in a patient with circumportal pancreas. We present a case of a successful subtotal pancreatectomy and splenectomy in a patient with circumportal pancreas, for a suspected pancreatic duct adenocarcinoma. The aim of this case report is to contribute valuable insights that can aid hepatobiliary surgeons in enhancing their preoperative planning when encountered with patients with similar anatomical variances.

Endoscopic Ultrasound in Pancreatic Duct Anomalies

Embryological development of the pancreas is a complex phenomenon and, therefore, it can have multiple developmental aberrations. Fortunately, the majority of these pancreatic ductal anomalies are asymptomatic with no clinical relevance and are incidentally detected during diagnostic cross-sectional imaging or endoscopic retrograde cholangiopancreatography (ERCP) or autopsy. Occasionally, pancreatic duct anomalies can result in symptoms like abdominal pain or recurrent pancreatitis. Also, an accurate pre-operative diagnosis of ductal anomalies can prevent inadvertent duct injury during surgery. Conventionally, ERCP had been used for an accurate diagnosis of pancreatic duct anomalies. However, because it is invasive and associated with a risk of pancreatitis, it has been replaced with magnetic resonance cholangiopancreatography (MRCP). MRCP has demonstrated high sensitivity and specificity for the diagnosis of ductal anomalies, which can be further improved with the use of secretin-enhanced MRCP. Endoscopic ultrasound (EUS) is a new diagnostic and interventional tool in the armamentarium of endoscopists and has demonstrated promising results in the detection of pancreatic duct variations and anomalies. Along with the visualization of the course and configuration of the pancreatic duct, EUS can also visualize changes in the pancreatic parenchyma, thereby helping with an early diagnosis of any co-existent pancreatic disease. Absence of the stack sign and crossed duct sign are important EUS features to diagnose pancreas divisum. EUS can also help with the diagnosis of other congenital ductal anomalies like annular pancreas, ansa pancreatica, and anomalous pancreaticobiliary union, although the published experience is limited.

The Role of Cross-Sectional Imaging in the Diagnosis of Agenesis of the Dorsal Pancreas: A Case Series

Background Agenesis of the dorsal pancreas is a rare entity and is caused due to the defective embryological development of the pancreas. The clinical manifestations may range from diabetes mellitus, pancreatitis, and abdominal pain to no symptoms at all. We here present a case series of 10 cases with complete or partial agenesis of the dorsal pancreas. Objectives To correlate the clinical symptoms in the patients with the dorsal agenesis of the pancreas, to study any biochemical abnormality present with the dorsal agenesis of the pancreas, and to look for other coexistent finding in the patients. Results We observed that out of 10 patients, six were males and four were females. Four had symptoms related to the pancreas and six were discovered incidentally. Diabetes mellitus was present in five patients, seven patients had pain in the abdomen, and jaundice was seen in three patients. Out of 10 patients, four had complete agenesis and six had partial agenesis of the dorsal pancreas. Conclusions We conclude that the diagnosis of this rare entity and establishing its association with clinical conditions like diabetes mellitus and non-specific abdomen pain with the aid of cross-sectional imaging helps in the better evaluation and management of the patients.

Correlation between Pancreatic Duct Variation and Related Diseases: An Effective Method Observing the Dual-Energy CT with Low-keV Monoenergetic Images

PURPOSE

Pancreatic duct variation can affect the secretory function of the pancreas. We aimed to explore the pancreatic duct variation, observed using low-keV monoenergetic images [MEI (+)] of dual-energy CT (DECT), and its relationship with related diseases. We further sought to compare pancreatic duct imaging using low-keV MEI (+) of DECT and magnetic resonance cholangiopancreatography (MRCP).

MATERIALS AND METHODS

The DECT and MRCP images of 854 patients were evaluated retrospectively. The 808 patients' pancreatic duct types were classified according to the anatomy and the opening of the pancreatic ducts, and the correlation with related diseases was analyzed. The DECT and MRCP images of 852 patients were graded according to the sharpness of the pancreatic ducts for evaluation.

RESULTS

A higher prevalence of acute pancreatitis (AP), chronic pancreatitis (CP), and duodenal papillary carcinoma (DPC) was observed in the variant group. Of the 27 AP cases in the variant group, 9 patients (33.3%) were Type 3c. Additionally, Type 4a was significantly correlated with AP and CP (p < 0.05). Low-keV MEI (+) of DECT outperformed the MRCP images in the sharpness of the pancreatic ducts in 852 patients.

CONCLUSIONS

Pancreatic duct variation is associated with AP, CP, and DPC. Low-keV MEI (+) DECT is an effective method to observe the pancreatic duct system.

Surgery

This chapter provides a comprehensive background from basic to applied knowledge of surgical anatomy which is necessary for the surgical treatment of cholangiocarcinoma (CCA) patients. Significant advances that have been made in the surgical treatment of CCA were examined. For instance, in-depth details are provided for appropriate preoperative assessment and treatment to optimize patient status and to improve the outcome of surgical treatment(s). Comprehensive details are provided for the surgical techniques and outcomes of treatments for each type of CCA with clear illustrations and images. This chapter also describes the role of minimally invasive surgery and liver transplantation in CCA treatment.

Pancreas bifidum: an extremely rare cause of acute pancreatitis

A wide spectrum of anomalies of the pancreas, the pancreatic ductal system and the biliary tree are commonly encountered at radiologic evaluation. Pancreas bifidum, also known as bifid pancreas or fish-tail pancreas, is an extremely rare congenital branching anomaly of the main pancreatic duct characterized by its duplication. These 2 separate ducts are laid from the pancreatic tail to neck and they generally join at the pancreas body-tail draining via the major papilla; the pancreatic parenchyma is also bifurcated with separated dorsal and caudal buds. The clinical impact of this condition is not well established: although some authors sustained that probably does not cause or contribute to abdominal pain or overt pancreatic diseases, others argued that could be considered as a possible cause of acute pancreatitis.

We herewith describe the case of a 51-year-old woman presenting to our hospital with epigastric pain, nausea, and vomiting. Biochemical tests were suspicious for acute pancreatitis. Ultrasound examination was negative. MRI, including MR cholangiopancreatography revealed bifid pancreas characterized by duplication of the main pancreatic duct with 2 separate ducts that join at the pancreas head and draining via the minor papilla. On T2-weighted images the ventral bud of the pancreas was enlarged and characterized by slightly hyperintensity without peripancreatic fluid collections. The MRI findings were consistent with acute pancreatitis limited to the ventral bud of a bifid pancreas. Patient was treated with intravenous fluid resuscitation, pain control and institution of early enteral nutrition and discharged on the seventh day after admission.

The Pancreas and Known Factors of Acute Pancreatitis

Pancreatitis is regarded by clinicians as one of the most complicated and clinically challenging of all disorders affecting the abdomen. It is classified on the basis of clinical, morphological, and histological criteria. Causes of acute pancreatitis can easily be identified in 75–85% of patients. The main causes of acute, recurrent acute, and chronic pancreatitis are gallstone migration and alcohol abuse. Other causes are uncommon, controversial, or unexplained. For instance, cofactors of all forms of pancreatitis are pancreas divisum and hypertriglyceridemia. Another factor that should be considered is a complication of endoscopic retrograde cholangiopancreatography: post-endoscopic retrograde cholangiopancreatography acute pancreatitis. The aim of this study is to present the known risk factors for acute pancreatitis, beginning with an account of the morphology, physiology, and development of the pancreas.

Congenital Anomalies of the Pancreas: Various Clinical Manifestations and Their Impact on Pancreatic Diseases and Outcomes

Background and objective: Congenital anomalies of the pancreas are relatively uncommon. Most of these are asymptomatic and are detected incidentally, but can present with a variety of clinical manifestations like pancreatitis, duodenal obstruction, biliary obstruction, and rarely malignancy. Here in our study, we describe various congenital anomalies of the pancreas associated with various clinical manifestations, its management strategies, and outcomes. The aim was to study the various clinical manifestations of and management strategies for pancreatic diseases associated with congenital anomalies of the pancreas and their outcomes.

Methods: A retrospective analysis of a prospectively maintained institutional database of 14 patients, admitted over a period of three years from June 2019 to May 2022, who were treated for different clinical manifestations of various congenital anomalies of the pancreas and their outcomes was done at our institution.

Results: The total number of congenital anomalies of the pancreas in our study was 14 out of whom 7 (50%) were males and 7 (50%) females. The mean age of the patients was 37 years. The most common congenital anomaly was pancreatic divisum in six (42.9%) cases. The most common clinical manifestation was acute pancreatitis in four (28.6%) cases. One (7.1%) case was incidentally detected intraoperatively for another condition. Eight (57.1%) patients underwent surgical intervention and six (42.9%) patients were medically managed. Mortality occurred in two (14.3%) cases. Associated alcohol consumption was seen in 2 (14.3%) cases; 10 (71.4%) patients had no comorbidities while 4 (28.6%) patients had diabetes mellitus. Out of eight (57.1%) surgical patients, two (25%) had Clavien-Dindo grade I and one patient (12.5%) grade V complications.

Conclusion: Congenital anomalies of the pancreas can be associated with a variety of clinical manifestations; their management strategies and outcomes are no different from patients with the same clinical manifestations with normal pancreatic development.

Pancreatic surface morphology and its classification

Introduction: Anomalies and variants of development of the pancreas are relatively frequent. These variations can often lead to misdiagnosis and unnecessary medical procedures. Although, pancreatic diseases are a constantly researched field, fundamental research is relatively understudied and re-evaluation of the pancreatic morphology is performed rarely.

Aim: The goal of the current study was to analyse pancreatic surface morphology by means of macroscopic anatomical dissection of 78 organ complex.

Material and methods: The anatomy of the pancreas was studied by means of macroscopic anatomical dissection. The study was performed on 78 organ complexes (the pancreas, spleen, and duodenum with surrounding abdominal fat) donated to the department of human anatomy from patients who died of causes not related to pancreatic diseases. The organs were fixed in a 10% formalin solution separately to accurately preserve their forms. The organs were measured by a caliper.

Results: The lie of the pancreas was classified according to Kreel and co-workers into 6 types: oblique shape in 11.54% of cases, sigmoid – 30.77%, transverse – 25.64%, horseshoe – 11.54%, L-shaped – 14.1%, and inverted V shape in 5.13%. Moreover, there were two possible L-shapes, the classical (8.97%) and inverted L-shape (5.13%). In one case, the pancreas had an unusual M-shape (1.28%). One specimen was a case of short pancreas (1.28%). Surface clefts were encountered in 17.95% of cases and in 5.13% of these cases, there was a branch of the splenic artery.

Conclusions: The current study demonstrates variations in the lie of the pancreas as well as several new possible variants. Moreover, we propose a modified classification based on these findings. Therefore, the pancreas can have an oblique, sigmoid, transverse, horseshoe, L shape, inverted L, inverted V, and M shaped lie. Pancreatic clefts are another frequently encountered variation that should be kept in mind. The size of the pancreas alone is variable and should be analyzed together with its structure to avoid possible misinterpretation.

Pancreatic morphological abnormality that was challenging to differentiate from an ectopic pancreas: a case report

Background

Protrusion of the lateral contour of the pancreatic head is a pancreatic morphological abnormality, which is known as rare shape atypia. We present a rare case of protrusion of the lateral contour of the pancreatic head, which was challenging to distinguish from an ectopic pancreas.

Case presentation

The patient was a 40-year-old man with a history of acute pancreatitis that occurred twice in the past. He complained of epigastric pain since the day before the visit; his blood workup showed high serum amylase level and a CT scan revealed a 25-mm-large mass with contrast effect from the anterior wall of the gastric pylorus to the duodenum and increased surrounding fatty tissue density. Endoscopic ultrasonography revealed a mass lesion in the gastric pylorus with continuity with the gastric wall and suspected partial continuity with the pancreatic head. Thus, the possibility of pancreatic morphological abnormality or an ectopic pancreas was considered. Following which, resection was attempted and intraoperative findings showed a wide extension of the pancreatic parenchyma from the pancreatic head to the anterior wall of the gastric pylorus to the duodenal bulb. Since the patient only had mild pancreatitis, the resection was judged to be too invasive and was completed by exploratory laparoscopy.

Conclusions

Even if the findings on preoperative CT are suspicious for an ectopic pancreas or tumor, a pancreatic morphological abnormality, such as a protrusion of the lateral contour of the pancreatic head, should be included in the differential diagnosis.

Development of the human pancreas and its exocrine function

The pancreas has both endocrine and exocrine function and plays an important role in digestion and glucose control. Understanding the development of the pancreas, grossly and microscopically, and the genetic factors regulating it provides further insight into clinical problems that arise when these processes fail. Animal models of development are known to have inherent issues when understanding human development. Therefore, in this review, we focus on human studies that have reported gross and microscopic development including acinar-, ductal-, and endocrine cells and the neural network. We review the genes and transcription factors involved in organ formation using data from animal models to bridge current understanding where necessary. We describe the development of exocrine function in the fetus and postnatally. A deeper review of the genes involved in pancreatic formation allows us to describe the development of the different groups (proteases, lipids, and amylase) of enzymes during fetal life and postnatally and describe the genetic defects. We discuss the constellation of gross anatomical, as well as microscopic defects that with genetic mutations lead to pancreatic insufficiency and disease states.

Investigation of annular pancreas through multiple detector spiral CT (MDCT) and MRI

BACKGROUND AND PURPOSE

To investigate annular pancreas in adults using imaging features displayed on computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS

Retrospective review of annular pancreas in patients undergoing CT or MRI examinations. Two abdominal radiologists blindly reviewed the CT, MRI, and magnetic resonance cholangiopancreatography (MRCP) images from the Picture Archiving and Communication Systems (PACS). A Kruskal-Wallis test was performed to evaluate subjective scoring, with Mann-Whitney test for the comparison. A p-value less than 0.05 was considered statistically significant.

RESULTS

Eleven patients (45.8%) presented a complete ring of pancreatic tissue surrounding duodenum, displayed as circular, triangular, or sandwich sign configuration, the other 13 patients (54.2%) had incomplete annular pancreas which displayed a crocodile jaw appearance, pancreatic tissue extending in a posterolateral or anterolateral direction towards duodenum. When comparing CT images of each sequence, the arterial phase group had the highest score compared with the venous phase and the plain film group (χ²  = 58.21, p < 0.05). When comparing MRI enhancement volumetric interpolated breath-hold examination (VIBE) sequences, arterial phase group scores were the highest (χ²  = 18.98, p < 0.05).

CONCLUSIONS

Both CT and MRI could detect annular pancreas, with artery phase being the best sequence to diagnose annular pancreas.

Ansa Pancreatica, an Uncommon Cause of Acute, Recurrent Pancreatitis

The pancreatic duct is vulnerable to developmental anomalies which may produce variations in its course and/or its configuration. Ansa pancreatica is the least common anatomic variant. It is characterized by the formation of an “S-shaped loop” from the main pancreatic duct to the minor papilla. Ansa pancreatica has been implicated as a cause of recurrent acute pancreatitis. We review existing literature on pancreatitis secondary to the ansa deformity and present a case of recurrent acute pancreatitis in a patient who was ultimately found to have the ansa deformity on endoscopic ultrasound.

Pancreatic involvement in patients with inborn errors of metabolism

Background

Repeated inflammation of the pancreas can cause pancreatitis or diabetes. It is well recognized that the organic acidemias may be complicated by pancreatitis but less recognized are other metabolic disorders in which pancreatitis can occur. This study shows that long-term follow-up of patients with various metabolic disorders in Korea revealed several with episodes of isolated pancreatitis or diabetes concomitantly with pancreatitis.

Results and discussion

In this study, two patients with methylmalonic aciduria (MMA), two with propionic acidemia (PPA), one with fatty acid oxidation disorder (FAOD), and one with hyperornithinemia, gyrate atrophy, and juvenile onset diabetes mellitus (DM) were clinically followed for up to 10 – 21 years. Two Korean siblings with MMA showed recurrent pancreatitis from the age of 15 and 19, respectively. The frequency of admission due to pancreatitis was up to 11 times. One patient with MMA developed diabetes mellitus at the age of 20. The other patient with MMA developed recurrent pancreatitis at 4 years and diabetes at 8 years of age. One of the patients with PPA presented with diabetic ketoacidosis. The other PPA patient died of cardiac arrest at age 10. The patient with FAOD presented with pancreatitis at 10 years and died at the age of 15 years due to cardiac arrest. A 35-year-old woman with hyperornithinemia/gyrate atrophy was diagnosed with juvenile onset diabetes at the age of 7 years. No pancreatitis occurred during the follow-up period.

Conclusions

We conclude that various metabolic disorders can trigger acute or chronic pancreatitis. Proper and prompt multidisciplinary management of metabolic derangement is crucial for preventing pancreatic damage. Further clinical and investigational studies are required to elucidate the pathogenesis of pancreatitis and diabetes mellitus in patients with inborn errors in metabolism.

Pancreas divisum inversus

Pancreatic duct variations are usually diagnosed incidentally, in particular when using magnetic resonance cholangiopancreatography (MRCP), the most accurate imaging modality for depicting the pancreatic ductal system. However, the frequency and the embryologic development of pancreatic variants have not been well investigated. The purpose of this prospective study was to investigate the frequency of pancreatic ductal variants, providing potential explanations of their embryologic basis. The pancreatic ductal anatomies of 202 patients with mean ± standard deviation (SD) age of 54 ± 27 years, 56% females, who underwent MRCP for different indications between April 2018 and March 2019, were prospectively collected. Normal pancreatic ductal variants were identified in 196 cases (97%), and variants of pancreas divisum in six cases (3%). In the type C variant of the normal pancreatic anatomy, found in 3% of the cases, the dorsal duct was joined to the ventral duct while the accessory duct did not communicate with the dorsal duct. Unlike the classic type C variant, in our cases, the accessory pancreatic duct (APD) was long (mean ± SD of 58 ± 8.5 mm) and originated in the lower portion of the pancreatic head, caudally to the duct of Wirsung. This was a new subtype of the type C variant or a new variant, which could be called "pancreas divisum inversus"; the APD could be called the isolated duct of Santorini. Reporting this new variant could increase knowledge regarding the pancreatic anatomy in order to avoid misdiagnosis and to help in better understanding pancreatic diseases and their relative treatment. Clin. Anat., 33:646-652, 2020. © 2019 Wiley Periodicals, Inc.

Biliary anatomy and pancreatic duct variations: A cross-sectional study

BACKGROUND/AIM

Biliary tree and pancreatic duct can appear in different variations whose proper understanding is obligatory for surgeons. Magnetic resonance cholangiopancreatography (MRCP) is considered a safe and accurate tool for evaluating biliary tree and pancreatic duct. Typical anatomy for right hepatic duct (RHD) and left hepatic duct (LHD) is reported as 57% and 63%, respectively. The most common (4-10%) pancreatic anomaly is divisum. In the present study, we evaluated and determined the prevalence of biliary tree and pancreatic duct variations among patients at a university hospital.

MATERIALS AND METHODS

The MRCP records of 370 patients from 2015 to 2017 were obtained for cross-sectional study. Images were retrospectively reviewed for variations by two independent senior radiologists. Demographic data were obtained for all the patients. Huang et al. classification was used for RHD and LHD variations. The cystic duct was reported based on its course and insertion pattern. The pancreatic duct was observed for the presence of divisum, its course, and configuration.

RESULTS

Three hundred and twenty-five patients were included in the final study. Most commonly observed variant for RHD were A1 (34.2%) and A2 (32.2%). For LHD, B1 (71.4%) was the most common variant. Cystic duct insertion was commonly seen as right lateral insertion (27.7%). Pancreatic divisum was observed in 0.6% of cases. Nationality, origin, and gender-specific variations were obtained.

CONCLUSION

Variations in biliary anatomy and pancreatic duct are very diverse and extend from the intrahepatic biliary system down to the pancreas. Performing a similar study on a larger population is mandatory to illustrate the range of variations present within the community.

Clinical importance of main pancreatic duct variants and possible correlation with pancreatic diseases

Background: Except for pancreas divisum (PD), the prevalence of anatomic variants of the main pancreatic duct (MPD) seems to be insufficiently investigated. To date, their role in the occurrence of pancreatic exocrine insufficiency (PEI) and morphological changes suggestive of chronic pancreatitis (CP) has remained unclear.Methods: A systematic review was performed, searching MEDLINE and Web of Science, limited to articles published between 1960 and 1 June 2019.Results: Our review included a total number of 3234 subjects. The most common variant of MPD was type 3, followed by type 1, indicating MPD drainage pattern into major papilla (MP) as the most frequent. A sub-variant of type 3, known as 'reverse pancreas divisum' had a prevalence of 2.2%. Type 4 variant- PD, was found in 6.4% of all cases. The most common sub-variant of PD was complete PD, followed by incomplete PD and variant with MPD as only pancreatic duct. Type 5 variant (including ansa pancreatica) was present in 2.9% of subjects. Apart from one study with a significantly higher frequency of morphological changes suggestive of CP in patients with ansa pancreatica, the studies stated no significant association between pancreatic disease and MPD variants. Furthermore, only one study examined the influence of MPD variants on exocrine pancreatic function. Although equivocal, this association is most likely found to be insignificant.Conclusion: To elucidate linkage between MPD variants and the occurrence of chronic pancreatitis and impairment of pancreatic exocrine function, further clinical investigations are warranted.

Trifidum anomaly of the main pancreatic duct

BACKGROUND

Embryology of the human pancreas is very complex and any alteration in its development may lead to congenital biliopancreatic malformations and anomalies not thoroughly studied in literature. We here report a case of trifurcation of the Wirsung duct, avery unusual variant of the main pancreatic duct.

METHOD

An 80- year-old woman underwent a magnetic resonance imaging (MRI) of the abdomen and a magnetic resonance cholangiopancreatography (MRCP) to characterize a hypoechoic lesion of the pancreas detected with ultrasonography.

RESULTS

MRI and MRCP showed a 24-mm multicystic lesion communicating with a prominent main pancreatic duct, consistent with an intraductal papillary mucinous neoplasm, as well as an ansa pancreatica. Moreover a bifidity of the distal pancreatic duct and a further accessory duct of the body of the pancreas draining into the main pancreatic duct were identified. The pancreatic tail presented normal size and morphology on axial imaging. This anomaly, not reported yet in the literature, can be categorized as a number of a duplication anomaly, in which the main pancreatic duct is trifurcated along its length.

CONCLUSION

Congenital anomalies of the pancreas and pancreatic duct are rare but not uncommonly detected on diagnostic imaging. MRI and MRCP are the non-invasive imaging modalities of choice for diagnosing congenital anomalies of the pancreas and the pancreatic duct.

Separate pancreatic ducts draining into a type IV choledochal cyst: simultaneous anatomical variants in a child suffering from cholelithiasis and acute pancreatitis

The biliary tree and the pancreatic ducts originate from different buds of the primitive foregut. A plethora of anatomical variants and congenital anomalies have been described for both the biliary and the pancreatic duct systems, although they are usually asymptomatic. However, in some cases, these abnormalities can lead to serious clinical scenarios, especially when involving the biliopancreatic junction, with consequent mixing and reflux of the two different juices. To the best of our knowledge, we present the first case of pancreas divisum ducts draining into a choledochal cyst, with the lower third of the choledochus configuring a common biliopancreatic duct, in a child suffering from cholelithiasis and acute pancreatitis.

Acute Pancreatitis in Pancreas Divisum Secondary to an Impacted Stone in the Minor Papilla

Pancreas divisum is reported to occur in up to 14% of the population. The majority of patients with this congenital anomaly remain asymptomatic. Pancreas divisum can be associated with recurrent pancreatitis due to inadequate drainage of pancreatic secretions through the dorsal pancreatic duct and the minor papilla. We present a patient with a six-month history of recurrent acute pancreatitis due to an impacted pancreatic duct stone in the minor papilla and an unrecognized pancreas divisum. This situation has only been reported in two other cases in the literature.

Various Congenital Abnormalities and Anatomic Variants of the Pancreas: A Pictorial Review

Numerous and various congenital abnormalities and anatomic variants of the pancreas (CAAVPs) have been reported. Some of them are not so uncommon. Recent advances and accessibility of various multiplanar imaging modalities today offer the increased capabilities of detection and full diagnosis of these CAAVPs. With a precise diagnosis, the symptomatic CAAVPs can not only be more specifically treated but even more their detection and exact description can modify the surgical or interventional strategy to avoid unexpected post-operative complications. This article aimed to review the embryogenesis of the pancreas and describe imaging findings of CAAVPs.

Neurog3-dependent pancreas dysgenesis causes ectopic pancreas in Hes1 mutant mice

Mutations in Hes1, a target gene of the Notch signalling pathway, lead to ectopic pancreas by a poorly described mechanism. Here, we use genetic inactivation of Hes1 combined with lineage tracing and live imaging to reveal an endodermal requirement for Hes1, and show that ectopic pancreas tissue is derived from the dorsal pancreas primordium. RNA-seq analysis of sorted E10.5 Hes1^+/+ and Hes1^-/- Pdx1-GFP⁺ cells suggested that upregulation of endocrine lineage genes in Hes1^-/- embryos was the major defect and, accordingly, early pancreas morphogenesis was normalized, and the ectopic pancreas phenotype suppressed, in Hes1^-/-Neurog3^-/- embryos. In Mib1 mutants, we found a near total depletion of dorsal progenitors, which was replaced by an anterior Gcg⁺ extension. Together, our results demonstrate that aberrant morphogenesis is the cause of ectopic pancreas and that a part of the endocrine differentiation program is mechanistically involved in the dysgenesis. Our results suggest that the ratio of endocrine lineage to progenitor cells is important for morphogenesis and that a strong endocrinogenic phenotype without complete progenitor depletion, as seen in Hes1 mutants, provokes an extreme dysgenesis that causes ectopic pancreas.

Frequency of bile duct confluence variations in subjects with pancreas divisum: an analysis of MRCP findings

PURPOSE

We aimed to evaluate the frequency of bile duct branching pattern variations at the hepatic confluence in patients with pancreas divisum (PD).

METHODS

A search was performed through the hospital database using the keyword "pancreas divisum" to identify patients. The magnetic resonance cholangiopancreatography (MRCP) images of 137 patients who were diagnosed with PD between August 2011 and November 2016 were retrospectively analyzed for the presence of bile duct variations. A control group of 137 patients without PD was established among patients investigated during the same period. Variations of the biliary tract were grouped into seven types according to the McSweeney et al. classification.

RESULTS

Biliary tract variations were detected in 103 of a total of 274 patients. Fifty-eight PD patients (42.3%) and 45 control patients (32.8%) had bile duct variation at the hepatic confluence level. The patients with PD were more likely to have biliary tract variation compared with the control group; however, it was not statistically significant (P = 0.105). The most common variation in PD patients was type 3a variation (16.8%).

CONCLUSION

MRCP studies showed atypical bile duct confluence pattern in nearly half of both PD patients and controls. There was no statistically significant difference in the frequency of anatomic variations at bile duct confluence in patients with PD versus those without PD. Derivation of these structures from different outpouchings in early embryological life may explain this insignificant difference.

The Main Anatomical Variations of the Pancreatic Duct System: Review of the Literature and Its Importance in Surgical Practice

Anatomical variations or anomalies of the pancreatic ducts are important in the planning and performance of endoscopic retrograde cholangiopancreatography (ERCP) and surgical procedures of the pancreas. Normal pancreatic duct anatomy occurs in approximately 94.3% of cases, and multiple variations have been described for the remaining 5.7%. The purpose of this study was to review the literature on the pancreatic duct anatomy and to underline its importance in daily invasive endoscopic and surgical practice. Two main databases were searched for suitable articles published from 2000 to 2017, and results concerning more than 8,200 patients were included in the review. The most common anatomical variation was that of pancreas divisum, which appeared in approximately 4.5% of cases.

A pictorial review of diagnostic pitfalls of developmental anomalies and variants in pancreatic imaging

Developmental anomalies and anatomic variants of the pancreas vary widely, and most of them are encountered incidentally during radiologic evaluation. However, some of these anomalies and variants are potentially pathologic and may cause various clinical presentations in childhood or adulthood. The early identification of these entities in various imaging modalities including ultrasound, computed tomography (CT), and magnetic resonance (MR) imaging would be valuable in making correct diagnoses and, in turn, preventing unnecessary additional procedures. In order to differentiate these entities, it is fundamental to understand the embryologic development and normal anatomical structure of the pancreas. In this article, we review the embryology and normal anatomy of the pancreas, and diagnostic pitfalls of developmental anomalies and anatomic variants in various pancreatic imaging modalities.

Closed loop of main duct of pancreas: a rare variant configuration

During routine dissection, duplication of main pancreatic duct extending from body to head region of pancreas was observed in a 78-year-old formalin fixed male cadaver. Main pancreatic duct gave a prominent branch which joined back the parent duct in head resulting in the formation of a closed loop. This gave the appearance of focal duplication in the form of a closed loop, an unusual variant. This was an incidental finding. Such cases usually remain asymptomatic; however, if undetected may be the cause of postoperative pancreatic fistula following pancreaticobiliary surgery. Knowledge of variable anatomy of pancreatic duct system became important to reduce the risk of postoperative complication and during various endoscopic guided procedures like drainage of pseudocyst or placement of stent into the duct.

A rare case of choledochal cyst with pancreas divisum: case presentation and literature review

Choledochal cysts are rare congenital malformations of the bile duct characterized by dilatations of the intrahepatic and/or extrahepatic portion of the biliary tree, they are associated to an anomalous arrangement of the pancreaticobiliary duct. Pancreas divisum results from a fusion failure of the pancreatic buds. The coexistence of pancreas divisum and choledochal cyst in adults has been reported in less than 10 well documented cases. This article presents a case of a 42-year-old Peruvian man with intermittent episodes of abdominal pain, initially diagnosed with choledocholithiasis, who underwent open cholecystectomy. During surgery, a diagnosis of choledochal cyst and pancreas divisum was made, and therefore a hepaticoduodenostomy was performed. The patient was referred to our hospital due to persistence of abdominal pain. After admission, a papillectomy was achieved without further complications. A cyst resection and dismantling of hepaticoduodenostomy with Roux-en-Y was performed 8 years later. During the subsequent 18-month follow-up, the patient remains asymptomatic.

On the development of the hepatopancreatic ductal system

The hepatopancreatic ductal system is the collection of ducts that connect the liver and pancreas to the digestive tract. The formation of this system is necessary for the transport of exocrine secretions, for the correct assembly of the pancreatobiliary ductal system, and for the overall function of the digestive system. Studies on endoderm organ formation have significantly advanced our understanding of the molecular mechanisms that govern organ induction, organ specification and morphogenesis of the major foregut-derived organs. However, little is known about the mechanisms that control the development of the hepatopancreatic ductal system. Here, we provide a description of the different components of the system, summarize its development from the endoderm to a complex system of tubes, list the pathologies produced by anomalies in its development, as well as the molecules and signaling pathways that are known to be involved in its formation. Finally, we discuss its proposed potential as a multipotent cell reservoir and the unresolved questions in the field.

Agenesis of the dorsal pancreas associated with mucinous adenocarcinoma and cystic teratoma: a case report and literature review

Dorsal agenesis of the pancreas is a rare congenital anomaly. Fifty‐eight cases were reported from 1913 till 2015, nine of which were associated with tumors. We present the 10th case, the first to be associated with pancreatic mucinous adenocarcinoma and cystic teratoma, successfully managed by Whipple procedure and total pancreatectomy.

Anatomic variations of the pancreatic duct and their relevance with the Cambridge classification system: MRCP findings of 1158 consecutive patients

BACKGROUND

The study was conducted to evaluate the frequencies of the anatomic variations and the gender distributions of these variations of the pancreatic duct and their relevance with the Cambridge classification system as morphological sign of chronic pancreatitis using magnetic resonance cholangiopancreatography (MRCP).

PATIENTS AND METHODS

We retrospectively reviewed 1312 consecutive patients who referred to our department for MRCP between January 2013 and August 2015. We excluded 154 patients from the study because of less than optimal results due to imaging limitations or a history of surgery on pancreas. Finally a total of 1158 patients were included in the study.

RESULTS

Among the 1158 patients included in the study, 54 (4.6%) patients showed pancreas divisum, 13 patients (1.2%) were defined as ansa pancreatica. When we evaluated the course of the pancreatic duct, we found the prevalence 62.5% for descending, 30% for sigmoid, 5.5% for vertical and 2% for loop. The most commonly observed pancreatic duct configuration was Type 3 in 528 patients (45.6%) where 521 patients (45%) had Type 1 configuration.

CONCLUSIONS

Vertical course (p = 0.004) and Type 2 (p = 0.03) configuration of pancreatic duct were more frequent in females than males. There were no statistically significant differences between the gender for the other pancreatic duct variations such as pancreas divisium, ansa pancreatica and course types other than vertical course (p > 0.05 for all). Variants of pancreas divisum and normal pancreatic duct variants were not associated with morphologic findings of chronic pancreatitis by using the Cambridge classification system. The ansa pancreatica is a rare type of anatomical variation of the pancreatic duct, which might be considered as a predisposing factor to the onset of idiopathic pancreatitis.

Afferent loop syndrome in a patient having incomplete annular pancreas

Afferent loop syndrome is a rare complication following a Billroth II procedure and is seen in 3/1000 cases. This case report shows the importance of radiological imaging in a patient with a past history of abdominal surgery, for which no records were available. Imaging showed incomplete annular pancreas, leading to narrowing of the second part of the duodenum, which was the indication for gastrojejunostomy in the past, now presenting with features of afferent loop syndrome.

Pancreatic Lipomatosis: An Extensive Pictorial Review

Pancreatic lipomatosis – also commonly called fat replacement – represents the most frequent benign pathologic condition of the adult pancreas. Most cases remain asymptomatic, and only some rare extreme degrees of lipomatosis or fat replacement may lead to exocrine pancreatic insufficiency.

The precise etiology of the entity remains unclear, and the condition has been found associated with several diseases comprising diabetes mellitus, metabolic syndrome, acquired or hereditary pancreatitis, alcoholic hepatitis, cystic fibrosis and condition comprising increasing age, body mass index, or more precisely visceral fat index, and use of steroid therapy. Numerous cases are also associated with condition compromising the permeability of the pancreas ductal system, such as intraductal calculus, pancreatic tumors, and congenital or experimental stenosis.

Uneven lipomatosis and fat replacement are also common presentations and responsible for the great diversity of imaging features. The reasons for uneven presentations are controversial and probably interweave embryologic or ductal hypotheses. Lipomatous pseudohypertrophy of the pancreas represents the most extreme situation of pancreatic lipomatosis and is considered, probably in a contestable way, as a rare, specific, and distinct entity.

We hereby present an extensive pictorial review of the broad spectrum of imaging features of this entity. The images are extracted from a compilation of cases collected in our department over more than a decade. We review and discuss the embryologic and ductal hypothesis, the differential diagnosis. Finally, we illustrate some unusual presentations and evolutions.

Polysplenia Syndrome With Splenic and Skeletal Muscle Metastases From Thyroid Carcinoma Evaluated by FDG PET/CT: Case Report and Literature Review: A Care-Compliant Article

Polysplenia syndrome (PSS) is a rare congenital abnormality. Metastases to spleen and skeletal muscle from differentiated thyroid cancer (DTC) are also extremely rare. Our case report aims to present an interesting case of PSS associated with splenic metastasis (SM) and skeletal muscle metastasis (SMM) from advanced papillary thyroid carcinoma which was evaluated on fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). An 84-year-old Chinese man was admitted with the history of multiple enlarged masses in bilateral neck, right axillary, and inguinal areas for >2 months. The results of ultrasonography examination were highly suggestive of malignancy. The histological results of the following biopsy were consistent with papillary thyroid carcinoma with involvement of multiple regional lymph nodes. He was referred for an FDG PET/CT imaging to evaluate the situation. FDG PET/CT showed that an intense FDG-avid thyroid mass with widespread regional lymph node involvement and distant metastases in the body. Unexpected sites of metastases were detected in the spleens and skeletal muscles. Most interestingly, FDG PET/CT imaging also described the typical imaging findings of PSS including the 2 right-sided spleens, azygos and hemiazygos continuation of inferior vena cava (IVC), right-sided stomach, middle line liver, a short pancreas, preduodenal portal vein (PPV), and malrotation of gut. Whole body FDG PET/CT imaging can accurately evaluate the situation of DTC by detecting regional lymph node involvement, common and rare sites of distant metastases which are closely related to staging, management, and prognosis of this disease. Whole-body FDG PET/CT is also valuable in demonstrating the typical imaging features of PSS.

Ectopic Opening of the Common Bile Duct Accompanied by Choledochocele and Pancreas Divisum

A 32-year-old woman was referred due to abdominal pain and elevated liver enzymes. Computed tomography and magnetic resonance imaging showed ectopic opening of the common bile duct (CBD) into the duodenal bulb. Esophagogastroduodenoscopy showed a hemispheric bulge in the duodenal bulb. Endoscopic retrograde cholangiopancreatography (ERCP) revealed the bulge to be cystic dilatation of the CBD. ERCP also showed no communication between the ventral and dorsal pancreatic ducts. We diagnosed the patient with ectopic opening of the CBD accompanied by choledochocele and pancreas divisum. Endoscopic incision was performed for the treatment of the choledochocele. The patient's symptoms and elevated liver enzymes improved after treatment.

Incidental finding of elongated ventral duct in a case of pancreatic divisum mimicking double pancreatic ducts on magnetic resonance cholangiopancreaticography-a rare normal variant

Anatomic variations and developmental anomalies of the pancreas and pancreatic duct are often noticed as an incidental finding on imaging. However, knowledge of these variants may prove to be crucial during surgery as it may prevent unintentional ductal injury. We report a case of pancreatic divisum with codominant ventral duct mimicking double pancreatic ducts along with the elongated uncinate process of pancreas. It was picked incidentally on magnetic resonance cholangiopancreaticography (MRCP) done to rule out cholelithiasis and choledocholithiasis. It is a rare anatomic variant and to the best of our knowledge has not been reported so far.

MRI Findings of Intrinsic and Extrinsic Duodenal Abnormalities and Variations

This pictorial review aims to illustrate the magnetic resonance imaging (MRI) findings and presentation patterns of anatomical variations and various benign and malignant pathologies of the duodenum, including sphincter contraction, major papilla variation, prominent papilla, diverticulum, annular pancreas, duplication cysts, choledochocele, duodenal wall thickening secondary to acute pancreatitis, postbulbar stenosis, celiac disease, fistula, choledochoduodenostomy, external compression, polyps, Peutz-Jeghers syndrome, ampullary carcinoma and adenocarcinoma. MRI is a useful imaging tool for demonstrating duodenal pathology and its anatomic relationships with adjacent organs, which is critical for establishing correct diagnosis and planning appropriate treatment, especially for surgery.

Imaging of the pancreatic duct by linear endoscopic ultrasound

The current gold standard investigation for anatomic exploration of the pancreatic duct (PD) is endoscopic retrograde cholangiopancreatography. Magnetic resonance cholangiopancreatography is a noninvasive method for exploration of the PD. A comprehensive evaluation of the course of PD and its branches has not been described by endoscopic ultrasound (EUS). In this article, we describe the techniques of imaging of PD using linear EUS.

"Ductal adenocarcinoma in anular pancreas"

INTRODUCTION

The annular pancreas is a congenital anomaly in which pancreatic tissue partially or completely surrounds the second portion of the duodenum. Its often located above of papilla of Vater (85%), rarely below (15%). This pancreatic tissue is often easily dissociable to the duodenum but there is same cases where it the tissue is into the muscolaris wall of the duodenum.

MATERIAL AND METHODS

We describe three case of annular pancreas hospitalized in our facility between January 2004 and January 2009. There were 2 male 65 and 69 years old respectively and 1 female of 60 years old, presented complaining of repeated episodes of mild epigastric pain. Laboratory tests (including tumor markers), a direct abdomen X-ray with enema, EGDS and total body CT scan were performed to study to better define the diagnosis. EUS showed the presence of tissue infiltrating the muscle layer all around the first part of duodenum. Biopsies performed found the presence of pancreatic tissue with focal areas of adenocarcinoma. Subtotal gastrectomy with Roux was performed. The histological examinations shows an annular pancreas of D1 with multiple focal area of adenocarcinoma. (T1aN0M0).

RESULTS

We performed a follow up at 5 years. One patients died after 36 months for cardiovascular hit. Two patients, one male and one female, was 5-years disease-free.

DISCUSSION

Annular pancreas is an uncommon congenital anomaly which usually presents itself in infants and newborn. Rarely it can present in late adult life with wide range of clinical severities thereby making its diagnosis difficult. Pre-operative diagnosis is often difficult. CT scan can illustrate the pancreatic tissue encircling the duodenum. ERCP and MRCP are useful in outlining the annular pancreatic duct. Surgery still remains necessary to confirm diagnosis and bypassing the obstructed segment.

Annular pancreas: the failure of side-to-side gastrojejunostomy anastomosis and the success of repair with Roux-en-Y gastrojejunostomy

Annular pancreas is a rare congenital anomaly characterized by a partial or complete encirclement of ectopic pancreas tissue around the duodenum. We report a case of annular pancreas in a 15 day-old infant admitted to the hospital with complaints of profuse and recurrent vomiting and loss of body weight. Non-contrast abdominal X-ray showed a dilated stomach with bubbles formation around the upper abdomen. An obstruction was noted and open laparotomy was performed. Upon laparotomy, pancreatic ring encircled the proximal duodenum causing an obstruction. Side-to-side gastrojejunostomy was performed and passage through the bypass was satisfactory. Four days after the operation, vomiting and bulging abdomen ensued. Contrast abdominal X-ray demonstrated filling defects at the level of obstruction and the anastomosis made. Anastomotic stricture was suspected and thus was corrected using Roux-en-Ygastrojejunostomy procedure. Postoperative course in this patient was satisfactory and patient was discharged after 24 days of hospitalization.

Accessory pancreatic lobe with gastric duplication cyst: diagnostic challenges of a rare congenital anomaly

Reports of combined congenital abnormalities of gastric duplication cysts and accessory pancreatic lobes are rarely reported. Patients with such anomalies may require appropriate surgical intervention tailored to the individual patient for complete cure. A multimodality diagnostic approach using ultrasonography, CT and MRI is useful for appreciation of the relevant anatomy of the congenital abnormality and for proper surgical planning. We present a case of a gastric duplication cyst with accessory pancreatic lobe and ectopic pancreatic rest in a 5-year-old child presenting with symptoms of recurrent pancreatitis.

Missing pancreatic isthmus during pancreaticoduodenectomy

Pancreatic malformations usually represent a surgical challenge, however, depending on the anatomical location even complex procedures such as pancreatic head resection may be facilitated. In a 78-year-old-woman the unique observation of a missing pancreatic isthmus was made during pylorus-preserving pancreaticoduodenectomy for pancreatic ductal adenocarcinoma. Resection of the pancreatic head could be performed without the usual cross-section at the isthmus, the pancreatic remnant was drained by pancreaticogastrostomy. Complete agenesis of the dorsal pancreas with missing neck, body and tail of the pancreas has been shown to be associated with malignant pancreatic tumors, as demonstrated in this case of partial agenesis (missing isthmus) of the dorsal pancreas. The missing pancreatic isthmus is a unique, not yet described finding during pancreatic exploration for tumor resection. In the absence of previous abdominal trauma, a partial agenesis of the dorsal pancreas could explain this malformation.

A study on the human pancreaticobiliary duct system and ampulla region with their clinical considerations

INTRODUCTION

The purpose of this study is to present the variations of the pancreatic duct system and hepatopancreatic ampulla so that an awareness of these variations may help in surgical planning and prevention of ductal injury.

METHODS

Forty human pancreatic specimens were used to study the duct pattern of the pancreas and the formation and mode of termination of the pancreatic ducts. Also, the patency of the main pancreatic ducts, length of the hepatopancreatic ampulla, and length of the main pancreatic duct were measured.

RESULTS

The main pancreatic duct was patent in 37 out of 40 specimens, 2 specimens showed the embryonic type of the duct system, and one had the duct obliterated at its duodenal end. The mode of termination of the main pancreatic and common pancreatic ducts was divided into four types. Seventy-five percent specimens belonged to type I, followed by type II in 22.5 % and type III in 2.5 % of specimens. The length of the main pancreatic duct ranged from 11 to 21.2 cm, the average being 17.3 cm, and the length of the hepatopancreatic ampulla varied from 1 to 10 mm (1 to 2 mm-5 %, 3 to 8 mm-55 %, and more than 8 mm in 15 % of specimens), and it was absent in 25 %.

CONCLUSION

Awareness of these anomalies may help in surgical planning and prevention of undue ductal injury.

Annular pancreas: a cause of gastric outlet obstruction in a 20-year-old patient

Patient: Female, 20

Final Diagnosis: Annular pancreas

Symptoms: Food intolerance • vomiting

Medication:—

Clinical Procedure: —

Specialty: Gastroenterology and Hepatology