Gangliocytic Paraganglioma of the Duodenum: A Masquerader

Abstract

Background: Gangliocytic paraganglioma (GP) is a rare tumor that most commonly arises from the duodenum and is characterized pathologically by 3 cell types: epithelioid, spindle, and ganglion cells. GP is often difficult to differentiate from a neuroendocrine tumor on the basis of preoperative imaging, and the diagnosis is based on final histopathologic and immunohistochemical analysis. Case Report: We report the case of a 28-year-old male who presented with pain in the abdomen, bilious vomiting, and weight loss. Imaging showed a mass involving the first and second part of the duodenum that was likely a neuroendocrine or gastrointestinal stromal tumor. He underwent robotic-assisted pancreatoduodenectomy, and the final pathology report identified GP with lymph node metastasis. The patient was doing well at 1-year follow-up. Conclusion: GP is often a histologic surprise as most cases are diagnosed in postoperative histopathology. While GP has a more benign course than a neuroendocrine tumor, radical surgical resection is warranted in cases of diagnostic dilemma, suspicion of malignancy, or lymph node metastasis. Robotic-assisted pancreatoduodenectomy is a feasible option.

Keywords: Duodenal neoplasms; paraganglioma; robotic surgical procedures.

Figure 1.

Magnetic resonance imaging of the upper abdomen. Duodenal mass (red arrows) appears isointense on (A) axial T2-weighted image and hypointense on (B) T1-weighted image. Diffusion restriction is seen in (C) diffusion-weighted image and corresponding (D) apparent diffusion coefficient map.

Figure 2.

Positron emission tomography with 2-deoxy-2-(fluorine-18)fluoro-D-glucose integrated with computed tomography (18F-FDG PET-CT). (A) Maximum intensity projection image shows focal FDG uptake in the subhepatic region and a few small foci of increased uptake in the abdomen in the midline. (B, D, and F) Fused PET-CT and (C, E, and G) CT images reveal intensely FDG-avid heterogeneously enhancing lesion along the medial wall of the first and second part of the duodenum. A few FDG-avid discrete metastatic lymph nodes are also seen in axial fused and CT images involving (H and I) the hepatoduodenal region (blue arrows) and (F, G, J, and K) the aortocaval region.

Figure 3.

(A) Resected pancreaticoduodenectomy specimen showing the bulky duodenal tumor (arrow) and the enlarged pancreaticoduodenal lymph node (arrowhead). (B) Low-power magnification shows tumor cells arranged in clusters and infiltrating the lamina propria and submucosa (hematoxylin and eosin stain [H&E], ×20 magnification). (C) Tumor clusters include epithelioid cells, spindle cells, and occasional ganglion cells (H&E, ×100 magnification). (D) Tumor cells are positive for synaptophysin (×40 magnification) and (E) neuron-specific enolase (×10 magnification).