SESSION TITLE: Pathology SESSION TYPE: Med Student/Res Case Report PRESENTED ON: 10/10/2018 03:45 PM - 04:45 PM INTRODUCTION: Primary cardiac tumors are a rare entity, with incidences reported as low as 0.02% -0.1%. Malignant cardiac tumors comprise 15% of all cardiac tumors. Cardiac sarcomas have many subtypes including angiosarcomas, myxomas, leiomyosarcomas, liposarcomas and fibrosarcomas. We present the only case report to our knowledge of a primary left atrial myxosarcoma presenting as dysphagia. CASE PRESENTATION: A 64 year old female with past medical history of type two diabetes mellitus initially presented with dysphagia. She had an esophagogastroduodenoscopy showing esophageal compression and gastritis but was lost to follow up. She then presented a year later complaining of dyspnea, orthopnea and chest pain for two months. She was in moderate distress, with a heart rate of 118 beats/min and blood pressure of 130/94 mmhg. Physical exam showed jugular vein distension and bilateral crackles. ECG showed sinus tachycardia with low QRS voltage. Labs revealed troponin I 0.02 ng/ml, BNP 56 pg/ml, and a D-Dimer of 2.2. Chest x-ray showed bilateral pulmonary edema. A CT angiogram revealed bilateral subsegmental pulmonary embolism and a 6.5 cm x 6 cm mass in the left atrium, encroaching the inferior vena cava and descending thoracic aorta. An echocardiogram also showed a large circumferential pericardial effusion, with features consistent with tamponade physiology. She underwent emergent pericardiocentesis and 850cc of serosanguinous fluid was drained. An endoscopic ultrasound guided biopsy of the mass was performed showing a posterior mediastinal mass compressing the esophagus with paratracheal lymphadenopathy. Biopsy was positive for high grade pleomorphic myxosarcoma. Due to the location and extensive involvement of the mass, patient was not an appropriate surgical candidate and was discharged with plan for chemotherapy as outpatient. She returned to the ER within the same month with recurrence of cardiac tamponade. She did not survive this episode. Subsequent autopsy revealed a left atrial myxosarcoma occupying 95% of the left atrium with pericardial studding, metastasis in the pulmonary arteries and lungs bilaterally. DISCUSSION: Myxosarcomas are exceedingly rare, accounting for 5% of cardiac sarcomas. They cause symptoms through numerous mechanisms. These tumors can release emboli into the circulation leading to widespread metastasis and thromboses. Obstruction of blood flow within the heart can cause heart failure. Involvement of the pericardium can cause effusion and tamponade.Through invasion of local structures they can produce compressive symptoms. CONCLUSIONS: This case demonstrates each of the aforementioned pathophysiologies. Treatment comprises of surgical resection, chemotherapy and radiation. Overall prognosis is guarded, with a mean survival between 6-12 months. This case brings to light an ominous yet easily overlooked cause of dysphagia that can prove to be rapidly fatal if left untreated. Reference #1: Lam KY, Dickens P, Chan AC. Tumors of the heart. A 20-year experience with a review of 12,485 consecutive autopsies. Arch Pathol Lab Med 1993; 117:1027. Reference #2: Sabatine MS, Colucci WS, Schoen FJ. Primary tumors of the heart. In: Zipes DP, Braunwald E, editors. Braunwald's heart disease: a textbook of cardiovascular medicine. 7th ed. Philadelphia: Elsevier Saunders; 2005. p. 1741–55. Reference #3: Sagrista-Sauleda J, Merce J, Permanyer-Maralda G, et al. Clinical clues to the causes of large pericardial effusions. Am J Med 2000; 109:95. DISCLOSURES: No relevant relationships by Mariam Aehtesham, source=Web Response No relevant relationships by khansa Ahmad, source=Web Response No relevant relationships by Aelia Fatima, source=Web Response No relevant relationships by Zoya Hussain, source=Web Response No relevant relationships by Sarah Usmani, source=Web Response