Case Report: When pancreatic cancer is not cancer: a rare case of pancreatic head paraganglioma with life-threatening delayed pseudoaneurysm bleeding

Background: Primary pancreatic paragangliomas are extremely rare neuroendocrine tumors that may radiologically and cytologically mimic pancreatic ductal adenocarcinoma. Importantly, paragangliomas may be functional tumors capable of secreting catecholamines, which can lead to severe hypertensive crises during biopsy or surgical manipulation if unrecognized. Case presentation: A 54-year-old male presented with intermittent abdominal pain. Cross-sectional imaging revealed a 13-mm mass in the pancreatic head. ERCP-guided duodenal brush cytology suggested malignant cells, and pancreaticoduodenectomy was performed. Final histopathological examination revealed primary pancreatic paraganglioma. The postoperative course was complicated by bile leakage requiring percutaneous transhepatic biliary drainage (PTBD) and life-threatening delayed pseudoaneurysm bleeding approximately three weeks after surgery, which was successfully treated with angiographic embolization. The patient's parents were not consanguineous and were not from the same village. There was no known family history of pheochromocytoma, paraganglioma, or MEN-related endocrine disorders. However, the family history revealed several malignancies, including breast cancer in the patient's sister at the age of 55, gastric and esophageal cancer in the father during his seventies, gastric cancer in two paternal uncles and one maternal aunt, laryngeal cancer in a paternal aunt, colon cancer in a maternal uncle, and lung cancer in another maternal uncle. Given this notable family cancer history, the patient was referred to the endocrinology and medical genetics departments, and a familial cancer genetic panel was requested. Conclusion: Pancreatic paragangliomas should be considered in the differential diagnosis of pancreatic head masses. Recognizing this rare entity is important not only for diagnostic accuracy but also for perioperative safety due to the potential risk of catecholamine-related complications during invasive procedures.