CT and MR Imaging Findings of Pancreatic Paragangliomas

Previous studies on pancreatic paraganglioma, a rare neoplasm, have primarily reported its ultrasound and routine and contrast-enhanced computed tomography (CT) findings. To our knowledge, we are the first to report the contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) sequence findings of pancreatic paraganglioma. A male patient, ages 41 years, was admitted to our hospital due to a pancreatic space-occupying lesion that had been present for more than 10 days. The patient had no obvious discomfort. He had a history of hypertension and hyperthyroidism. Physical examination revealed upper abdominal tenderness without a palpable mass. Routine and contrast-enhanced abdominal CT showed a soft tissue mass at the pancreatic head/uncinate process, with patchy calcification within the lesion. On a contrast-enhanced CT scan, severe enhancement of the mass in the arterial phase was noted, as was slightly reduced but still marked enhancement in the venous phase. The celiac trunk and superior mesenteric artery segment were wrapped by the tumor. Thickened, tortuous vessels were observed at the lesion edges, around which there were multiple enlarged lymph nodes. The main pancreatic duct was markedly dilated. Routine and contrast-enhanced pancreatic MRI demonstrated an abnormal nodular signal in the pancreatic head/uncinate process that was approximately 4.3 × 6.4 cm² in size. T1-weighted imaging (T1WI) revealed hypointensity, whereas T2-weighted imaging (T2WI) revealed nonhomogeneous, slight hyperintensity. Patchy hypointensity on both T1WI and T2WI was observed within the lesion. DWI showed slight hyperintensity. Grossly heterogeneous enhancement of the mass was observed on a contrast-enhanced MRI scan, with the tumor wrapped around the adjacent vasculature, and multiple enlarged lymph nodes were observed peripherally. After preoperative preparation, the patient underwent pancreatoduodenectomy. Histopathology and immunohistochemistry of the resected tumor indicated pancreatic paraganglioma. After surgery, the patient recovered well, without presenting any recurrence or metastasis during short-term follow-up. For hypervascular pancreatic tumors on contrast-enhanced CT or MRI, and particularly those occurring in the pancreatic head, with a clear display of draining veins, the possibility of pancreatic paraganglioma should be considered. These tumors usually exhibit necrosis or cystic changes and are occasionally accompanied by calcification.