Gastroduodenal artery aneurysm simulating a pancreatic neuroendocrine neoplasm: an important pitfall and potential misdiagnosis

Pancreatic neuroendocrine neoplasms (PanNENs) and visceral artery aneurysms can present with similar imaging features, posing diagnostic challenges. We report a case of a 33-year-old male with an incidental pancreatic neck/body lesion initially suspected to be a PanNEN based on arterial enhancement patterns seen on MRI. Endoscopic ultrasound was inconclusive, and biopsy was deferred pending further evaluation. A subsequent pancreas-protocol CT with advanced 3D reconstruction identified the lesion as a 10 mm gastroduodenal artery aneurysm (GDAA), associated with celiac artery stenosis caused by median arcuate ligament syndrome (MALS). This accurate diagnosis helped avoid an unnecessary biopsy, which could have caused serious complications. The case emphasizes the importance of considering vascular lesions in the differential diagnosis of pancreatic masses and demonstrates the critical role of thorough imaging evaluation in guiding safe and effective patient management.