Successful Laparoscopic-Assisted Pancreaticoduodenectomy for a Neuroendocrine Tumor of the Papilla of Vater in Type 1 Portal Annular Pancreas

Abstract

Introduction: Portal annular pancreas (PAP) is a rare anomaly of pancreatic embryology that is classified into three types according to the position of the main pancreatic duct. PAP type 1, in which the main pancreatic duct runs dorsal to the pancreas, is extremely rare. Herein, we describe a case of successful laparoscopic-assisted pancreaticoduodenectomy in a patient with type 1 PAP.

Case presentation: A 72-year-old Japanese woman with neck swelling was referred to our hospital. CT at admission showed dilation of the main pancreatic duct. After a thorough examination, a preoperative diagnosis of carcinoma of the papilla of Vater was made. Neck swelling was attributed to a lymphoma for which chemotherapy was administered. Upon remission, CT imaging indicated PAP type 1, and a laparoscopic-assisted pancreaticoduodenectomy was performed. The retroportal pancreas was dissected just below the portal vein, but anastomosis was difficult; therefore, the pancreas was moved to the anterior surface of the portal vein, and anastomosis was performed. Postoperative pancreatic leakage occurred but was relieved by drainage, and the patient was discharged 26 days postoperatively. The postoperative diagnosis was neuroendocrine tumor of the papilla of Vater.

Conclusions: Only one case of open pancreaticoduodenectomy for PAP type 1 has been reported previously. We successfully removed a neuroendocrine tumor from the papilla of Vater in a patient with PAP type 1 through laparoscopic-assisted pancreaticoduodenectomy and detailed the operative procedures for optimal outcomes in future cases.

Keywords: laparoscopic surgical procedures; laparoscopic-assisted pancreaticoduodenectomy; pancreaticojejunostomy; portal annular pancreas; postoperative pancreatic fistula.

Fig. 1. Endoscopic retrograde cholangiopancreatography image. Swelling is observed in the papilla of Vater, with ulceration observed below the orifice.

Fig. 2. Hematoxylin and eosin staining. Carcinoma cells with eccentric nuclei infiltrating the mucosa in the duodenal biopsy specimen.

Fig. 3. CT and MRCP images. (A) Dilation of the main pancreatic duct observed on CT imaging (red arrow). (B) The portal vein parenchyma is observed on the anterior surface of the pancreas (white triangle), but the dilated main pancreatic duct is located dorsal to the portal vein (red arrow). (C) Slightly dilated main pancreatic duct observed dorsal to the portal vein (red arrow). (D) MRCP shows dilatation of the main pancreatic duct with no obvious abnormality.

MRCP, magnetic resonance cholangiopancreatography

Fig. 4. Anatomical relationship of the pancreas and portal vein, showing the main pancreatic duct coursing posterior to the portal vein.

Fig. 5. Laparoscopic images. (A) Tunneling and taping of the retroportal pancreas (RP) just above the PV. (B) Pancreatic dissection of the anteportal pancreas (AP) was performed using a Powered ECHELON FLEX. (C) Anteportal pancreas (AP) was dissected with a stapler. (D) The anteportal pancreas is dissected and taped to the vessels.

Fig. 6. Laparoscopic images. (A) The PV and SMV are pulled to the left side of the patient, and an ultrasound of the retroportal pancreas (RP) is performed to confirm the location of the main pancreatic duct and bile duct. (B) The RP is dissected using an ultrasonic coagulation incision. (C) Following RP dissection, the surrounding area is dissected, and the RP is pulled out at the left margin of the PV. (D) Before anastomosis, a slightly dilated main pancreatic duct is observed on the dissected surface of the RP.

PV, portal vein; SMV, superior mesenteric vein

Fig. 7. Hematoxylin and eosin staining and immunostaining. (A) The tumor cells with eosinophilic cytoplasm were proliferated in an alveolar pattern with rich vascularized stroma (black arrows). (B) Immunohistochemically, the tumor cells were positive for INSM-1 (black arrows). (C) The tumor cells were diffusely positive for synaptophysin. (D) The tumor cells were diffusely positive for the somatostatin receptor.