Abstract Body (Do not enter title and authors here): Case Presentation:
An 87-year-old woman with atrial fibrillation, Parkinson’s disease and cardiovascular risk factors, presented to the ED with two weeks of progressive dyspnea and orthopnea. Chest X-rays from 2021 through 2023 showed progressive cardiomegaly, but there was no history of known heart failure or prior echocardiography.

On admission, her labs showed proBNP was 3,474 pg/mL and troponin-I HS was 101 ng/L. TTE demonstrated a large right ventricular mass with near-complete cavity obliteration and reduced RV systolic function and normal LVEF. Cardiac MRI showed an 8.7 x 4.1 x 3.8 cm lobulated mass adherent to the myocardium, obstructing inflow and outflow tracts and creating pseudo-stenosis of the tricuspid and pulmonic valves. Despite markedly reduced RV stroke volume and compression, the patient was clinically stable, normotensive, and denied chest pain or syncope.

She underwent right heart catheterization with biopsy, which confirmed intimal sarcoma, a rare and normally aggressive mesenchymal malignancy. She was deemed not to be a surgical candidate due to her comorbidities. She has otherwise been asymptomatic and will follow up with her oncologist in the outpatient setting.

Discussion:
This case demonstrates an extraordinarily rare intimal sarcoma of the right ventricle causing both inflow and outflow tract obstruction and severely reduced stroke volume, yet presenting with minimal clinical instability. The patient’s hemodynamic resilience, despite dramatic structural compromise, likely reflects chronic tumor progression, an uncommon occurrence in this otherwise aggressive tumor type. This has allowed for physiologic adaptation, reflected in her hemodynamic stability.

The findings underscore the importance of correlating anatomic imaging with clinical and hemodynamic presentation, especially in elderly patients. Previous cardiomegaly without cardiac workup suggests missed opportunities for earlier detection. This case also emphasizes the role of multimodality imaging, histopathologic confirmation, and flexible, goal-concordant care planning in cardio-oncology. Cardiac MRI with the use of parametric mapping, perfusion and late gadolinium enhancement is a pivotal step in the evaluation of undifferentiated cardiac masses which can then be confirmed with biopsy. Intimal sarcoma should be considered in patients with unexplained RV dysfunction or intracardiac masses, even in the absence of systemic symptoms.