Portal vein aneurysm mimicking a pancreatic mass: A case report with an emphasis on imaging pitfalls

Portal vein aneurysm (PVA) is a rare vascular abnormality that may mimic pancreatic or peri-pancreatic masses. We report a case of a woman in her 50s who was referred to our hospital after an annual routine medical check-up revealed a suspected pancreatic cyst. Initial non-contrast MRI and multiphase contrast-enhanced CT demonstrated a round enhancing lesion adjacent to the portal venous confluence, raising suspicion for a hypervascular pancreatic tumor. Subsequent endoscopic ultrasonography with Doppler confirmed turbulent venous flow within the lesion, consistent with a portal vein aneurysm. The lesion gradually regressed during follow-up. This case highlights the importance of including vascular lesions in the differential diagnosis of pancreatic masses and demonstrates the diagnostic role of Doppler-enhanced ultrasonography and multiphase CT.