Primary retroperitoneal paraganglioma simulating a pancreatic mass: a case report and review of the literature

Abstract

Paragangliomas are extra-adrenal tumors of the autonomic nervous system and may be found within the skull base, neck, chest, and abdomen. When presenting within the abdominal cavity, they may arise as a primary retroperitoneal neoplasm and can mimic vascular malformations or other conditions related to specific retroperitoneal organs such as the pancreas, kidneys, or adrenals. Retroperitoneal paragangliomas are mostly benign with good prognosis; however, they can present with abdominal pain, palpable mass, or hypertensive episodes. Patients should be initially evaluated with catecholamine levels, followed by computed tomography or magnetic resonance imaging to locate the primary lesion. Surgical excision remains the mainstay of treatment, although advanced disease and proximity to vital organs can make excision difficult or impossible. This case report describes a patient who initially underwent work up for a suspected pancreatic head mass which was discovered to be a retroperitoneal paraganglioma by frozen section.

Figure 1

Axial noncontrast CT abdomen demonstrates a retroperitoneal soft tissue lesion (arrowheads) with lobulated margins and a central calcification. Prominent vessels are noted around the lesion. The second duodenal portion contacts the mass (arrow).

Figure 2

Axial contrast enhanced CT abdomen shows a hypervascular retroperitoneal mass (arrowheads) with enlarged surrounding vessels (large arrow). No cleavage plane is noted between the duodenum and the mass (short arrow). Also the mass contacts the inferior vena cava (IVC).

Figure 3

Contrast enhanced CT abdomen. Curved multiplanar reconstruction demonstrates an intimal relation of the retroperitoneal paraganglioma, and the proximal pancreas, duodenum (d), and IVC. Pancreatic body and tail show parenchymal atrophy and pancreatic ductal dilatation (arrows). SMA: superior mesenteric artery.

Figure 4

Paraganglioma composed of dual cell population arranged in characteristic nested pattern “zellballen” (20x).

Figure 5

Synaptophysin (brown immunohistochemical stain) confirms neuroendocrine origin, supporting the diagnosis of paraganglioma (20x).

Figure 6

Axial contrast enhanced CT abdomen. Two years imaging follow-up shows interval decrease in size of the paraganglioma. Perilesional fat stranding is related to prior surgical procedure and radiation therapy (arrowhead).