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

Laparoscopic Distal Pancreatectomy for Lymph Node Metastasis around Splenic Artery from Hepatocellular Carcinoma in a Patient with Portal Annular Pancreas

INTRODUCTION

Lymph node metastases after hepatocellular carcinoma (HCC) resection exist, although they are not common. However, solitary metastasis to the splenic artery lymph node with suspected pancreatic invasion after HCC resection is rare. In certain cases, surgical resection is performed to improve patient outcomes. We report a case of lymph node metastasis resected by laparoscopic distal pancreatectomy (LDP) in a patient with a unique anatomical anomaly known as portal annular pancreas (PAP).

CASE PRESENTATION

A 79-year-old Japanese man underwent laparoscopic left lateral segmentectomy for HCC. Two months after the surgery, alpha-fetoprotein levels remained elevated. Plain computed tomography revealed a swollen lymph node along the splenic artery involving the pancreas and the PAP. We suspected a solitary metastasis to the lymph node around splenic artery with pancreatic invasion. LDP was performed for complete resection of lymph node metastasis. Although the patient developed a grade B postoperative pancreatic fistula, he was discharged on postoperative day 33 under conservative treatment of antibiotics. He has remained recurrence-free for 4 years and 3 months after surgery.

CONCLUSIONS

LDP was successfully performed for lymph node metastasis around the splenic artery in an HCC patient and resulted in long-term survival. Surgeons should be aware of the unique anatomical characteristics of PAP during LDP.

A Robotic Pancreaticoduodenectomy Case Involving a Meandering Main Pancreatic Duct Coursing Posterior to a Replaced Common Hepatic Artery and in Front of the Portal Vein

INTRODUCTION

Anatomical anomalies, such as branches of the celiac artery and superior mesenteric artery (SMA), and pancreatic malformations, including the annular pancreas, are important during pancreaticoduodenectomy (PD). Here, we report a case of an anomaly of the artery and main pancreatic duct (MPD) in which the pancreatic parenchyma surrounded the replaced common hepatic artery (rCHA), and the meandering main pancreatic duct (MMPD) ran behind the rCHA.

CASE PRESENTATION

A 71-year-old woman was diagnosed with intraductal papillary mucinous neoplasm (IPMN) of pancreatic body and the dilation of MPD to 13 mm, which was a factor of high-risk stigmata. Preoperative computed tomography (CT) showed that the rCHA branched from the superior mesenteric artery (SMA) and the pancreatic parenchyma surrounded the rCHA. Moreover, the MPD meandered and ran behind the rCHA. PD was performed. At the time of dissection between the rCHA and pancreatic parenchyma, we had to divide not only the cranial part of the pancreatic parenchyma along the rCHA but also the MPD. The postoperative course was uneventful.

CONCLUSION

This is the first report of the rCHA surrounded by pancreatic parenchyma and MMPD running behind the rCHA and in front of the portal vein.

Robotic pancreaticoduodenectomy for portal annular pancreas: how to do it

Portal annular pancreas (PAP) is an uncommon anomaly in which the pancreatic parenchyma surrounds the portal or superior mesenteric vein. An adequate operative approach is necessary to prevent clinically relevant postoperative pancreatic fistula after pancreaticoduodenectomy for PAP. We herein report a case of robotic pancreaticoduodenectomy for PAP. In PAP, dissection of the retroportal parenchyma is the most important aspect of surgery. Adequate retraction of the portal system using vessel loops allows for a safe dissection and transection of the retroportal parenchyma. The robotic approach has some advantages for dissecting the retroportal parenchyma. The magnified three-dimensional view helps the surgeon distinguish the nerve plexus from the pancreatic parenchyma. The caudal view allows for direct dissection of the retroportal parenchyma from the superior mesenteric artery. Dissection can easily be performed using articulated forceps. Owing to these advantages, robotic pancreaticoduodenectomy can be safely performed for PAP.

Pancreatic ultrasound: An update of measurements, reference values, and variations of the pancreas

Reliable and reproducible measurement methods have been established, and reference values are used in almost all scientific disciplines. Knowledge of reference values is crucial to distinguish physiological from pathological processes and, therefore, subsequently, for the clinical management of patients. Image storage and documentation of measurements and normal findings should be part of quality assurance in imaging. This paper aims to review the published literature and provide current knowledge of sonographic measurements and reference values of the pancreas. Moreover, the role of clinical influencing factors such as age, gender, constitution, and ethnicity is also analyzed.

Minimally invasive pancreaticoduodenectomy for circumportal pancreas: literature review and report of two type IIIA cases

BACKGROUND

Circumportal pancreas is a rare morphological variant with clinical significance due to the high risk of postoperative pancreatic fistula in patients undergoing pancreaticoduodenectomy. Type IIIA (suprasplenic anteportal) is the most common type of circumportal pancreas. We present two cases of type IIIA treated with minimally invasive pancreaticoduodenectomy, and review the literature on patients with circumportal pancreas who underwent pancreatic surgery.

CASE PRESENTATION

Case 1: Laparoscopic Pancreaticoduodenectomy for Non-functioning Pancreatic Neuroendocrine Neoplasm with Circumportal Pancreas. A 69-year-old female with no prior medical history presented with a pancreatic head mass detected during routine ultrasound. CT revealed a 20 mm hypervascular tumor in pancreas head and a suprasplenic circumportal pancreas with an anteportal duct. The main pancreatic duct (MPD) was not in the parenchyma on the dorsal side of the portal vein (PV). Laparoscopic pancreaticoduodenectomy was performed. The anteportal side was resected with an ultrasonic device, and the retroportal side with a mesh-reinforced stapler. Pancreaticojejunostomy was performed without complications. Case 2: Robot-assisted Pancreaticoduodenectomy for Pancreatic Head Cancer and Non-functioning Pancreatic Neuroendocrine Neoplasm in the pancreatic tail with Circumportal Pancreas. A 72-year-old male with no prior medical history presented with a dilated main pancreatic duct on ultrasound. Diagnosed with pancreatic head cancer (Stage IIA), he underwent neoadjuvant chemotherapy. Contrast-enhanced CT revealed pancreatic cancer in the head and a tumor in the tail with unknown pathology. Robot-assisted pancreaticoduodenectomy was performed, and pancreatectomy on the left side of the tail tumor was planned. Intraoperative findings revealed a circumportal pancreas with the MPD not running through the dorsal parenchyma. After resected the parenchyma on the left side of the tail tumor, parenchyma on the dorsal side of the PV was dissected using SynchroSeal®. Pancreaticojejunostomy was performed without complications. The postoperative course was uneventful.

CONCLUSIONS

The optimal location and method of pancreatic resection should be selected according to the type of circumportal pancreas and the location of the lesion to be resected to minimize the risk of pancreatic fistula. Minimally invasive surgery for circumportal pancreas remains challenging even for surgical teams with sufficient experience and skills, and careful consideration are necessary for its application.

Robotic Pancreatoduodenectomy in Portal Annular Pancreas Using a Hanging Maneuver with Indocyanine Green Fluorescence Imaging

BACKGROUND

Sufficient knowledge and surgical management of portal annular pancreas (PAP) are essential for pancreatic surgery. As PAP is a relatively rare pancreatic anomaly, few studies have described surgical techniques for patients with PAP undergoing robotic pancreatoduodenectomy (RPD).

PATIENTS AND METHODS

An 82-year-old female patient who underwent RPD presented with distal cholangiocarcinoma and type III PAP (the fusion of the uncinate process with the anteportal main pancreatic duct). After the Kocher maneuver and stomach transection, the pancreas was transected into the neck of the anteportal portion. The retroportal portion was dissected, encircled with hanging tape, and compressed. Blood supply from the mesenteric vessels was confirmed using indocyanine green (ICG) fluorescence imaging. Subsequently, the retroportal portion was stapled.

CONCLUSIONS

This study demonstrates a unique surgical technique for type III PAP using the hanging maneuver with ICG fluorescence imaging. Surgeons should decide on the surgical strategy on the basis of the fusion and ductal anatomy of the 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.

Pancreaticoduodenectomy in the Portal Annular Pancreas-Mesopancreas Triangle Approach (with Video)

BACKGROUND

Portal Annular Pancreas (PAP) is a relatively uncommon entity with 4% reported incidence. Pancreaticoduodenectomy is challenging in cases with PAP and is associated with higher postoperative pancreatic fistula rate and overall morbidity. PAP is classified according to the pattern and location of fusion around the portal vein as-supra-splenic, infra-splenic & mixed fusion type. Also, the ductal anatomy can vary as pancreatic duct present only in the ante-portal portion or only in the retro-portal portion or ducts in both ante and retro-portal portion. At present, ideal surgical strategy is not defined as per the PAP types.

METHODS

The case demonstrated in the video presented with a localized, large duodenal mass with type IIA PAP (supra-splenic fusion with both ante and retro-portal ducts) detected on the preoperative triphasic CT scan. To achieve a single pancreatic cut surface with a single pancreatic duct for anastomosis, an extended pancreatic resection was performed using meso-pancreas triangle approach.

RESULTS

Patient had a smooth intraoperative course & the postoperative recovery was also uneventful. Pathology reported pT3 duodenal cancer with negative margins and uninvolved lymph nodes.

CONCLUSION

A preoperative knowledge of PAP and its various types is extremely important in order to tailor intraoperative management, specially of the retro-portal portion. In patients with retro-portal duct or both ante and retro-portal ducts (as the case presented in the video), an extended resection is recommended to mitigate postoperative pancreatic fistula.