Portal annular pancreas: An unsual pancreatic pseudotumor with clinical significance

Abstract

Portal annular pancreas (PAP) is a rare congenital anomaly due to abnormal fusion of ventral pancreatic bud left to the developing portal vein. Its incidence is 1.1%–3.4% in the literature. PAP is commonly involving the uncinate process; complete encircling is relatively rare. Proposed hypothesis for the congenital PAP is (1) hypertrophied ventral pancreatic bud fuses with the body of the pancreas left to the portal vein and (2) malformation of the portal vein. We found a bulky pancreas in a 51-year-old male during an autopsy. After careful dissection, we observed that the pancreas was completely encircling around the portal vein cranial to its formation. The encircled tissue was confirmed as normal pancreatic tissue by H and E and immunohistochemical staining. Pancreatic ductal pattern was observed anterior to the portal vein. This condition is usually asymptomatic; most of the time, the same was diagnosed incidentally during surgery. However, in cases of the malignant lesion in the head of the pancreas, the PAP is usually confused as the tumor's extension (pseudotumor). The management of posttransection pancreatic stump is challenging and usually results in complications such as pancreatic fistula. Knowledge about the PAP is necessary for the surgeon and radiologist for accurate diagnosis and prior planning to prevent the postoperative complications.