Circumportal pancreas: A report of two cases

Abstract

Circumportal pancreas (CP) is an unusual pancreatic anomaly occurring in 1.1 to 2.5% of individuals, where there is abnormal fusion of the uncinate process to the main pancreatic body occurring to the left of the portal vein-superior mesenteric vein (PV-SMV) junction. Since it was first described in 1987, there have only been a few reports documented in the literature. We recently encountered 2 such cases. Patient 1 was an 81-year-old man who presented with weight loss. Computed tomography (CT) scan revealed an atrophic pancreas with dilated pancreatic duct and a nodule at the head of pancreas, suspicious for a main-duct intraductal papillary mucinous neoplasm (IPMN) with malignant change. During surgery, we discovered that the uncinate process of the pancreas was completely wrapped around the SMV and fused with the main body, resulting in encasement of the PV-SMV junction. The patient also had a replaced right hepatic artery (RHA). Patient 2 was a 76-year-old man who complained of several weeks of abdominal discomfort. A CT scan showed a dilated common bile duct with a distal mass, worrisome for distal cholangiocarcinoma. Intra-operatively, he was similarly found to have union of the uncinate process of the pancreas with the main body occurring to the left of the PV-SMV confluence, with bilateral anomalous hepatic arteries. We present a brief review of the literature surrounding this condition. Although CP is usually asymptomatic, failure to recognize it may lead to serious consequences.

Keywords: Annular; Circumportal; Pancreas; Portal.

Fig. 1. Intra-operative photograph of patient 1 showing the uncinate process of the pancreas fused with the main body, encircling the superior mesenteric vein-portal vein junction (with blue vessel loop).

Fig. 2. Resected specimen of patient 1 with staple line indicating where the fused uncinate process was divided. The surgical ruler delineates the path of the superior mesenteric vein and portal vein.

Fig. 3. Computed tomography scan of patient 1 showing the uncinate process fused to the main body (white arrow) and dilated anteportal and retroportal pancreatic ducts.

Fig. 4. Computed tomography scan of patient 2 showing fused uncinate process fused to the main body, to the left of superior mesenteric vein-portal vein confluence (white arrow).

Fig. 5. Computed tomography scan of patient 2 showing fused uncinate process fused to main body, to the left of the superior mesenteric vein-portal vein confluence (white arrow).

Fig. 6. Computed tomography scan of patient 2 showing fused uncinate process fused to the main body, to the left of superior mesenteric vein-portal vein confluence (white arrow).