Right Atrial Cardiac Fibroma Mimicking Eustachian Valve Endocarditis in Neutropenic Sepsis

BACKGROUND: Management of an undifferentiated right atrial (RA) mass in a septic, immunocompromised patient is challenging when imaging and microbiologic data are discordant. CASE SUMMARY: A 51-year-old kidney transplant recipient presented with neutropenic sepsis and a newly identified RA mass. Transesophageal echocardiography suggested eustachian valve endocarditis, whereas cardiac magnetic resonance imaging favored thrombus. Percutaneous aspiration, performed for therapeutic debulking, incidentally failed to mobilize the mass, suggesting firm adherence and low embolic potential. This informed discontinuation of poorly tolerated anticoagulation and deferral of high-risk surgery. Elective resection 2 months later revealed a cardiac fibroma. DISCUSSION: Evidence guiding management of indeterminate RA masses is limited. Resistance to aspiration may provide functional information about embolic risk. TAKE-HOME MESSAGES: RA fibromas can mimic thrombus or endocarditis, particularly in septic, immunocompromised patients. In select patients already undergoing percutaneous aspiration, incidental procedural resistance may indicate stability and lower embolic risk.