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.