An extremely rare portal annular pancreas for pancreaticoduodenectomy with a special note on the pancreatic duct management in the dorsal pancreas

Two Cases of a Portal Annular Pancreas in Patients Undergoing Pancreaticoduodenectomy

Introduction

Portal annular pancreas (PAP) is a congenital anomaly resulting from aberrant fusion of the ventral and dorsal pancreatic buds around the portal vein (PV). PAP was classified into three types by Joseph et al., based on the location of the main pancreatic duct around the PV. The presence of PAP is important for the surgical procedure because it is associated with the postoperative pancreatic fistula. There are no standardized surgical procedures of resection and reconstruction for PAP.

Case Presentation

We report 2 cases of subtotal stomach-preserving pancreatoduodenectomy in patients with PAP. One case of PAP was discovered coincidentally intraoperatively, and the other case was diagnosed before surgery. The first case was an 84-year-old male patient who underwent surgery for distal bile duct cancer. PAP was noticed intraoperatively when the uncinate process of the pancreas was detached from behind the PV. The second case was an 84-year-old female patient who also underwent surgery for distal bile duct cancer. We recognized PAP from preoperative computed tomography images. In both cases, the ductal anatomy was consistent with type IIIA PAP, and the dorsal pancreas was resected using a stapling device. During the postoperative period, there was no clinically relevant postoperative pancreatic fistula.

Conclusion

PAP is rarely encountered intraoperatively; however, it is important to recognize it before surgery and take it into consideration when deciding upon the procedures for resection and reconstruction.

Surgical management of intraoperatively diagnosed portal annular pancreas: Two case reports

RATIONALE

Portal annular pancreas (PAP) is a rare pancreatic anomaly characterized by portal vein encasement in the pancreatic parenchyma. Due to its rarity, PAP may often be missed on preoperative computed tomography (CT) review, and surgeons may face challenges in dealing with an unexpected intraoperative encounter with PAP. We documented 2 such intraoperatively diagnosed cases and illustrated their surgical management.

PATIENTS CONCERNS

In case 1, a 70-year-old man was found to have a 15-mm mass in the pancreatic body and dilatation of the peripheral main pancreatic duct on enhanced CT. Case 2 involved a 46-year-old woman with a history of familial adenomatous polyposis, and rectal cancer with a mass in the duodenal papilla.

DIAGNOSES

The patient in case 1 was diagnosed with resectable pancreatic cancer. In case 2, the patient was diagnosed with duodenal papillary carcinoma.

INTERVENTIONS

In case 1, the patient underwent distal pancreatectomy with lymph node dissection. In case 2, the patient underwent pancreaticoduodenectomy. Intraoperatively, PAP was observed in both cases. In case 1, after the usual transection at the right border of the portal vein, an additional dissection was performed on the dorsal pancreas using a powered linear stapler. In case 2, an additional section was made in the pancreatic body caudal to the cricoid pancreatic junction so that the pancreatic cross-section was oriented in 1 plane.

OUTCOMES

The patient in case 1 was discharged without complications. In case 2, although the patient had a grade-B pancreatic fistula (International Study Group of Pancreatic Fistula Classification), the patient recovered conservatively and was discharged without significant complications. In both cases, a retrospective review identified PAP in patients' preoperative CT images.

LESSONS

Both cases required ingenuity during pancreatectomy. Awareness about PAP and its management will enable surgeons to prepare for unexpected encounters with the condition. Moreover, surgeons (especially pancreatic surgeons) should consider the possibility of PAP while managing pancreatic anomalies to make appropriate treatment decisions.

Portal Annular Pancreas With Common Hepatic Artery Trajectory Abnormality: A Case Report and Review of the Literature

ABSTRACT

Portal annular pancreas (PAP) is a rare congenital pancreatic anomaly, in which the uncinate process of the pancreas fuses to the body of pancreas behind the portal vein. Here, we report a case of PAP with common hepatic arterial anomaly, which was identified during surgery. A 57-year-old man who had branch type intraductal papillary mucinous neoplasm in the head of the pancreas developed a nodule in the cystic lesion. We planned pylorus preserving pancreaticoduodenectomy. The common hepatic artery from the celiac artery passing behind the portal vein was revealed in preoperative examinations. During surgery, we discovered that the uncinate process of the pancreas was fused with the body of the pancreas behind the portal vein. We divided the pancreas at the anterior and posterior of the portal vein. The main pancreatic duct was present in the anterior pancreatic stump. We performed pancreaticojejunostomy in the anterior stump and closed the posterior stump by interrupted suture. Forty-four surgical cases of PAP have been reported in the English medical literature. There are few previous reports of PAP which involved an arterial anomaly. Clinicians should consider PAP preoperatively to ensure that the surgeon can appropriately plan pancreatic resection to avoid postoperative complications.

Portal Annular Pancreas (PAP): an Underestimated Devil in Pancreatic Surgery-Systematic Review of Literature and Case Report

INTRODUCTION

Portal annular pancreas (PAP) is an anatomic variation due to aberrant fusion of the ventral and dorsal pancreatic buds around the portal vein. In this article, we present a case report with a systematic review of literature of patients undergoing major pancreatic surgery with associated PAP. We also intend to discuss and suggest possible surgical strategies to minimise major postoperative complications.

METHODS

A systematic literature search was conducted using the terms "circumportal," "periportal," "pancreas," "annular pancreas," "portal annular pancreas" and "pancreas anomaly." All articles describing portal annular pancreas with surgical resection were included.

RESULTS

We identified a total of 53 patients of PAP from 29 articles, who underwent pancreatic resection with a median age of 65 years. POPF (postoperative pancreatic fistula) was demonstrated in 42.55% of patients and 34% had CR (clinically relevant)-POPF. Following pancreaticoduodenectomy, pancreatic stump was reconstructed in all patients with either pancreaticojejunostomy or pancreaticogastrostomy. Standard line of pancreatic transection, i.e., division of anteportal portion at the pancreatic neck and stapling of the retroportal process, resulted in 71% incidence of CR-POPF, whereas it was only 16% when extended resection was performed to achieve single pancreatic stump and 12.5% when retroportal portion was sutured or ligated. Amongst distal pancreatic resections, 66% had POPF and 33% developed CR-POPF.

CONCLUSION

It is of utmost importance for pancreatic surgeons to diligently look for and identify PAP in the preoperative imaging. Additional imaging in the form of MRCP helps to define abnormal pancreatic ductal anatomy. Surgeons need to be cognisant of pancreatic stump management in patients with PAP to reduce associated higher rates of POPF.

Circumportal pancreas - a hazardous anomaly in pancreatic surgery

BACKGROUND

Circumportal pancreas (CP) is an anatomical anomaly in the form of abnormal parenchymal fusion between the uncinate process and the pancreatic body, and it requires an additional parenchymal dissection during pancreaticoduodenectomy (PD). This study aimed to investigate the prevalence of CP in PD and to evaluate the incidence of postoperative pancreatic fistula (POPF) among CP patients.

METHODS

Patients who underwent PD from 2002 to 2012 (n = 552) were included. Operative records and preoperative images were independently reviewed to identify the presence of CP. The incidence of POPF was compared between CP and non-CP patients and was evaluated via multivariate analysis.

RESULTS

CP was confirmed from operative records in 7 (1.3%) patients, and abnormal parenchymal fusion was identified from preoperative images in 8 (1.4%) patients. The incidence of POPF was significantly higher in CP patients than in non-CP patients (71% vs 32%, P = 0.039). On multivariate analysis, CP was an independent predictive factor for POPF (odds ratio, 9.97; 95% confidence interval, 1.76-56.6; P = 0.009).

DISCUSSION

Surgeons should heed the presence of CP in PD because this rare anomaly requires an additional parenchymal dissection and may increase the incidence of POPF.

Management of portal annular pancreas during laparoscopic pancreaticoduodenectomy

Portal annular pancreas (PAP) is a pancreatic congenital anomaly consisting of pancreatic parenchyma encircling the portal vein and/or the superior mesenteric vein. It has been reported that the risk of developing a post-operative pancreatic fistula is higher following pancreaticoduodenectomy in patients with PAP, probably because of the possibility of leaving undrained a portion of pancreatic parenchyma during the reconstructive phase. Few manuscripts have reported a surgical technique of pancreaticoduodenectomy in case of PAP, herein we report the first case of a patient with PAP undergoing laparoscopic pancreaticoduodenectomy.

Radical antegrade modular pancreatosplenectomy for adenocarcinomaof the body of the pancreas in a patient with portal annular pancreas, aberrant hepatic artery, and absence of the celiac trunk: A case report

RATIONALE

Portal annular pancreas is a rare anatomic variation, where the uncinated process of the pancreas connects with the dorsal pancreas and the pancreas tissue encases the portal vein (PV), superior mesenteric vein (SMV) or splenic vein (SV). Malignancies are quite uncommon in the patients, who have an annular pancreas especially portal annular pancreas. Ectopic common hepatic artery and absence of the celiac trunk (CT) are the other infrequent abnormalities.

PATIENT CONCERNS

A 74-year-old man suffered from upper abdominal and back pain.

DIAGNOSES AND INTERVENTIONS

Contrast enhanced computed tomography indicated a low-density mass in the body of the pancreas. Pathological report showed adenocarcinoma of the body of pancreas after radical antegrade modular pancreatosplenectomy (RAMPS).

OUTCOMES

In the operation, we found the superior vein and portal vein was surrounded by the pancreatic tissue. The left gastric artery and splenic artery originated respectively from abdominal aorta, and celiac trunk was not viewed. In addition, the common hepatic artery was a branch from the superior mesenteric artery.

LESSONS

In general, this is a novel clinical case of pancreatic carcinoma happening in the portal annular pancreas which was accompanied with aberrant hepatic artery and absence of the celiac trunk at the same time. Confronted with the pancreatic neoplasms, the possibility of coexistent annular pancreas and arterial variations should be considered.

Successful resection of pancreatic head cancer in a patient with circumportal pancreas: a case report with technical consideration

We report a case of pancreaticoduodenectomy for pancreatic head cancer with circumportal pancreas (CP). A 76-year-old woman was referred to our hospital with complaint of generalized pruritus. Dynamic computed tomography (CT) revealed an unenhanced mass at the head of the pancreas and a dilated main pancreatic duct (MPD) behind the superior mesenteric vein (SMV). She was diagnosed with pancreatic head cancer with CP and underwent subtotal stomach-preserving pancreaticoduodenectomy (SSpPD). The pancreas was transected both beneath and above the SMV, and the dominant dorsal edge of the pancreas was mobilized and anastomosed with the gut, whereas the ventral edge was closed by suture and attached to the gut. The postoperative course was uneventful without the occurrence of pancreatic fistula or bleeding. CP is a rare anomaly in which a portal vein (PV) is encircled by the annular pancreatic parenchyma. CP is usually asymptomatic without any significant comorbidity but may become a surgical hazard when pancreaticoduodenectomy is performed. We report our successfully treated case, with special references to the technical approach for pancreatic anastomosis.

Circumportal Pancreas-a Must Know Pancreatic Anomaly for the Pancreatic Surgeon

PURPOSE

Circumportal pancreas is a rare congenital pancreatic anomaly with encasement of the portal vein and/or the superior mesenteric vein by pancreatic tissue. It is often overlooked on cross-sectional imaging studies and can be encountered during pancreatic surgery. Pancreatic head resection with circumportal pancreas is technically difficult and bears an increased risk of postoperative pancreatic fistula.

MATERIALS AND METHODS

A retrospective chart review of our data base for all patients who had undergone pancreatic head resection between 2004 and 2015 was performed.

RESULTS

We identified six patients out of 1102 patients who had undergone pancreatic head surgery in the study period. CT-scan and MRI were never able to identify circumportal pancreas prior to surgery. The right hepatic an artery derived from the superior mesenteric artery in four cases (67%). Additional resection of the pancreatic body was always performed. Postoperative course was uneventful in all cases without occurrence of pancreatic fistula.

CONCLUSIONS

Circumportal pancreas is a rare entity every pancreatic surgeon should be aware of. It is difficult to identify on cross-sectional imaging studies. A right hepatic artery arising from the superior mesenteric artery should raise suspicion of circumportal pancreas. Additional pancreatic tissue resection should be performed during pancreatic head resections to avoid pancreatic fistula.

Portal Annular Pancreas: A Rare and Overlooked Anomaly

Background

Portal annular pancreas is a rare pancreatic developmental anomaly which is often overlooked at imaging, and often diagnosed retrospectively when it is detected incidentally at the time of surgery. Although the anomaly itself is asymptomatic, it becomes important in cases where pancreatic resection/anastomosis is planned, because of varying ductal anatomy, risk of ductal injury and increased risk of postoperative pancreatic fistula formation.

Case Report

We present imaging findings in a case of portal annular pancreas in a 45-year-old male patient.

Conclusions

Portal annular pancreas is a rare and often neglected pancreatic anomaly due to a lack of awareness of this entity. With the advent of MDCT and MRI, accurate preoperative diagnosis of this condition is possible.

Pancreaticogastrostomy Prevents Postoperative Pancreatic Fistula of Portal Annular Pancreas During Pancreaticoduodenectomy

Portal annular pancreas (PAP) is an asymptomatic congenital pancreatic anomaly in which the uncinate process of the pancreas extends and fuses to the dorsal surface of the body of the pancreas by surrounding the portal vein and or the superior mesenteric vein. During pancreaticoduonectomy (PD), the presence of PAP significantly increased risk for postoperative pancreatic fistula (POPF) because specific management of 2 pancreatic resection planes with 1 or 2 pancreatic ducts is required for pancreatico-intestinal reconstruction. To reduce the risk of POPF, a shift of the resection plain to the left for 1 anastomosis is recommended. We report a case of PAP that was successfully performed PD with pancreaticogastrostomy (PG). PG was conducted with invagination of the 2 resected pancreatic planes together into the stomach to minimize resected volume of the pancreas. A 78-year-old male patient with PAP underwent PD due to a duodenal adenocarcinoma. Intraoperatively, the uncinate process extended extensively behind the portal vein and fused with the dorsal surface of the pancreatic body above the splenic vein. For pancreatico-intestinal reconstruction, PG was performed with invagination of the 2 resected pancreatic planes together into the stomach. The postoperative course was uneventful, and he was discharged on postoperative day 12. Endocrine and exocrine function of the pancreas were maintained well at 10 months after surgery. PG is one of the useful choices for patients with PAP to prevent POPF while maintaining the pancreatic endocrine and exocrine function after PD.

Circumportal pancreas: a review of the literature and image findings

PURPOSE

Fused pancreatic tissue encasing the portal and/or superior mesenteric vein, circumportal pancreas, is a congenital anomaly that has been associated with operative complications in resections involving the head of the pancreas. We describe this anomaly and highlight its pathophysiology and surgical outcomes through a review of the literature to date, drawings and a computed tomography example.

METHODS

A literature search was undertaken using Pubmed and the search terms "circumportal pancreas," "annular pancreas" and "pancreatic anomaly."

RESULTS

91 cases of circumportal pancreas were identified in the literature. The number of reported cases increased with time. 14 were documented as having undergone surgery (11 carcinoma or suspected carcinoma/3 benign neoplasm). Surgical outcome was reported in 13. Five of 13 (38.5 %) experienced a fistula. Three cases were treated with a drain. One incident of potentially unnecessary surgery due to the misidentification of circumportal pancreas was noted.

CONCLUSIONS

(1) The identification of circumportal pancreas is increasing but is relatively rare. (2) Varying locations of the main pancreatic duct can induce inappropriate construction during pancreaticojejunostomy and can influence the risk of fistula. In the presence of CP, distal pancreatectomy with pancreatic division in front of portal vein creates two sources of pancreatic fistula. (3) The high incidence of associated vascular variants can directly influence pancreatic resection and can affect vascular reconstruction for complete oncologic resection. Therefore, the preoperative location of the main pancreatic duct and presence of any vascular variants in CP must be systematically identified before programed surgery.

Portal annular pancreas: a systematic review of a clinical challenge

Portal annular pancreas (PAP) is an asymptomatic congenital pancreas anomaly, in which portal and/or mesenteric veins are encased by pancreas tissue. The aim of the study was to determine the role of PAP in pancreatic surgery as well as its management and potential complication, specifically, postoperative pancreatic fistula (POPF).On the basis of a case report, the MEDLINE and ISI Web of Science databases were systematically reviewed up to September 2012. All articles describing a case of PAP were considered.In summary, 21 studies with 59 cases were included. The overall prevalence of PAP was 2.4% and the patients' mean (SD) age was 55.9 (16.2) years. The POPF rate in patients with PAP (12 pancreaticoduodenectomies and 3 distal pancreatectomies) was 46.7% (in accordance with the definition of the International Study Group of Pancreatic Surgery).Portal annular pancreas is a quite unattended pancreatic variant with high prevalence and therefore still remains a clinical challenge to avoid postoperative complications. To decrease the risk for POPF, attentive preoperative diagnostics should also focus on PAP. In pancreaticoduodenectomy, a shift of the resection plane to the pancreas tail should be considered; in extensive pancreatectomy, coverage of the pancreatic remnant by the falciform ligament could be a treatment option.

Circumportal pancreas: a clinicoradiological and embryological review

Circumportal pancreas is a congenital fusion anomaly of the pancreas where the pancreatic tissue from the uncinate process, anomalously encases the portal vein and/or the superior mesenteric vein. Depending upon the level of the pancreatic annulus the variant can be classified into three subtypes-suprasplenic, infrasplenic or mixed; and each subtype exhibits either an anteportal or retroportal main pancreatic duct. Limited literature is available on this intriguing anomaly primarily because of its relatively low prevalence in humans (published prevalence rates vary from 0.2 to 2.5 %), probable lack of awareness among medical professionals and its generally symptomless course. In an attempt to appraise the embryological basis, clinicoradiological manifestations and potential surgical implications of circumportal pancreas, literature published in English was searched using PubMed and information collated so as to provide up-to-date information on this relatively understudied entity. The anomaly by itself remains innocuous but its preoperative recognition in those undergoing pancreatic resection bears decisive influence on planning and selecting apposite surgical resection planes as inadvertent duct injury can lead to pancreatic fistula.