SUN-493 An Unusual Case of Right Atrial Paraganglioma

Abstract Disclosure: A. Faber: None. R. Simon: None. Introduction: Paragangliomas are extra-adrenal neuroendocrine tumors derived from the embryonic neural crest cells. A portion of these tumors release catecholamines into the bloodstream, resulting in an array of symptoms often with a temporal component. Classically, patients present with episodic symptoms of headache, palpitations, sweating, and flushing. In this way, paragangliomas are similar to pheochromocytomas which are colloquially termed intra-adrenal neuroendocrine tumors. Paragangliomas account for 15% of chromaffin cell tumors though are generally located in the head, neck, or abdomen. Cardiac paragangliomas are extremely rare occurring in under 0.3% of mediastinal tumors. We present an extremely unique case of a right atrial paraganglioma. Case Presentation: A 45-year-old Nigerian male with history of prediabetes and GERD presented to the emergency room with shortness of breath. Physical exam showed a blood pressure of 133/66 mmHg, a pulse of 94 beats/minute, a respiratory rate of 20 breaths/minute, and normal temperature. EKG showed normal sinus rhythm. Cardiac markers were not elevated. Chest CT scan showed a 6 x 6 x 7 cm right atrial solid mass, possibly involving the myocardium. Patient was transferred to the intensive care unit where he underwent the following work up. Chest MRI demonstrated a 6.2 x 6.5 x 7.8 cm avidly enhancing ovoid mass adjacent to the right atrium. Left heart catheterization revealed normal coronary arteries except the right coronary artery was supplying significant blood supply to the highly vascularized large right atrial mass. Patient later underwent right atrial mass excision with cardiac surgery which required extensive surgical exploration as well as cardiac and vascular reconstruction with bovine tissue. Patient remained hemodynamically stable throughout surgery. The formal pathology report from the mass noted an extra-adrenal paraganglioma. Endocrinology was then consulted. Upon further history-taking, the patient revealed a one-year history of episodic palpitations, flushing, sweating, and anxiety. Episodes were sporadic at first but became more frequent, occurring multiple times per week. He denied any recurrence of these episodes since surgery. Prior to mass excision, no plasma or urine metanephrines were collected. Plasma metanephrines collected five days after mass excision were negative. The patient was referred to Genetics for further testing to guide follow up. Discussion: Intracardiac paragangliomas are extremely rare, accounting for <1% of all cardiac tumors. Most documented cases involve paragangliomas in the left atrium, thus making this case even more atypical. Our case fortunately had no major surgical complications despite lack of alpha blockade. This unique case reminds us the importance of considering paragangliomas in cardiac tumors for proper preparation prior to surgery. Presentation: Sunday, July 13, 2025