Ampullary Gangliocytic Paraganglioma Treated With Endoscopic Mucosal Resection

Abstract

Introduction: Gangliocytic paragangliomas (GPs) are rare submucosal neuroendocrine tumors, consisting of epitheliod, spindle and ganglion cells. Ninety percent of these tumors are located in the periampullary portion of the duodenum, and occasionally in the esophagus, jejunum and pancreas. The differential includes gastrointestinal stromal tumors (GISTs) and ampullary adenomas. The clinical presentation varies and includes gastrointestinal bleeding, abdominal pain, jaundice and pancreatitis. These lesions can be asymptomatic and incidentally found during endoscopy. Case Report: 51 year-old male presented initially to an outside medical center with 2 weeks of periumbilical pain. Physical exam noted moderate midepigastric tenderness. Laboratory values were normal. Abdominal ultrasound noted a hypoechoic mass surrounding the pancreatic head, no pancreatic and biliary dilation noted. Abdominal contrast computerized tomography revealed a 2 cm solid homogenous mass in the proximal duodenum. Upper endoscopy (EGD) revealed an ampullary mass; biopsies suggested an adenoma with low grade dysplasia. The patient elected for endoscopic resection and was referred to our institution. An ERCP revealed a 2 cm ampullary mass that was resected via snare electrocautery. A temporary pancreatic duct stent was placed for pancreatitis prevention and a biliary sphincterotomy was performed to facilitate post-procedural biliary drainage. Microscopic and immunohistochemical tissue analysis revealed epithelioid, spindle and ganglionic cells staining positive for synaptophysin, S-100, neuron specific enolase (NSE), and somatostatin consistent with a gangliocytic paraganglioma. Resection margins were negative. Discussion: GPs carry inherent malignant potential with documented cases of both regional lymph node and distant metastases. Previous case series note metastasis rates of seven percent. Current first line management is endoscopic mucosal resection as reported here. GP recurrence post-resection is exceedingly rare. Surgical pancreatoduodenectomy is often performed if endoscopic resection is not possible or positive margins are observed. Radiotherapy is now being utilized as adjuvant therapy for patients with regional metastasis. Chemotherapy has not been formally investigated. As more cases of GPs are reported, oncologic management of advanced lesions and post-resection surveillance strategies will need to be further investigated and defined.