Successful Endoscopic Resection of a Rare Minor Ampullary Duodenal Gangliocytic Paraganglioma: A Case Report

Abstract

Duodenal gangliocytic paragangliomas (DGP) are extremely rare neuroendocrine tumors. We present a case of a successful endoscopic resection of an incidental DGP. A 61-year-old Caucasian male with a history of cholecystectomy, iron deficiency anemia and GERD was incidentally found to have a 1.3cm periampullary duodenal polyp without any lymphadenopathy on a routine CT scan. The findings were confirmed with an abdominal MRI. He denied abdominal pain, early satiety, nausea, diarrhea, constipation, flushing, wheezing, weight loss, melena or any family history of gastrointestinal malignancies. An EUS examination showed markedly enlarged minor papilla with a hypoechoic mass and intact muscularis propria. A prominent pancreatic duct (PD) was also visualized. The EUS was followed by an ERCP to resect the polyp and a 5Fx4cm stent was placed in the PD due to high suspicion of pancreatic divisum. The specimen was a tan-colored, well-circumscribed 1.3x0.8x1cm soft, polypoid mass. Histologically, it was mostly a submucosal mass with a focal mucosal component. It exhibited a triple cellular differentiation with the epithelioid tumor cells arranged in nests along with occasional ganglion-like cells and surrounding scant spindle cells without atypia. The margins were clean. The epithelioid cells stained strongly positive for synaptophysin and chromogranin, and weakly positive for keratin. They were negative for S100, gastrin and somatostatin. The spindle cells stained positive for S100, synaptophysin and were negative for keratin. The mitotic active was low with a Mib-1 proliferative index of 3%. A 6-month follow up EGD with minor ampullary biopsy showed no signs of dysplasia or malignancy. DGPs are extremely rare and non-functional neuroendocrine tumors. They are twice more prevalent in males and usually found in the 6th to 7th decades of life. They are mostly benign tumors with excellent prognosis post resection. However, there have been about 20 case reports with lymph node metastasis and 1 report of fatal metastatic DGP. Traditionally, pancreaticoduodenectomy has been the treatment of choice when lymph nodes are involved. However, endoscopic resection, as in this case, remains a safe alternative for a localized DGP. In the lack of official guidelines, more studies are required to understand the nature of the disease, optimal treatment and follow up duration.Figure: Duodenal Gangliocytic Paraganglioma, ultrasound view.Figure: Duodenal Gangliocytic Paraganlioma, endoscopic view.Figure: The ampulla post resection.