Papillary Endothelial Hyperplasia Mimicking Right Atrial Infective Thrombus

BACKGROUND: Intracardiac masses pose a diagnostic and therapeutic challenge, with clinical features overlapping infective endocarditis, thrombus, and primary cardiac tumors. Papillary endothelial hyperplasia (PEH) is a benign intravascular lesion rarely reported in intracardiac locations, potentially indistinguishable from infected thrombus on echocardiography. CASE SUMMARY: A 75-year-old man with multiple comorbidities presented in septic shock secondary to Enterococcus faecalis bacteremia. A DENOVA score of 3 prompted transesophageal echocardiography, revealing a 2 × 1.2 cm mobile right atrial mass at the superior vena cava-right atrial junction. Percutaneous thrombectomy using the AngioVac system was performed. Histopathology demonstrated CD31-positive papillary endothelial proliferation without infection or malignancy, consistent with PEH. DISCUSSION: PEH can mimic infected intracardiac thrombus. AngioVac enabled simultaneous therapeutic debulking and definitive tissue diagnosis in a high-risk surgical patient. TAKE-HOME MESSAGE: When bacteremia and an intracardiac mass coexist, tissue acquisition is essential, as PEH may satisfy modified Duke criteria yet remain indistinguishable from infected thrombus by echocardiography alone.