Case report: endocarditis or catheter-related right atrial thrombosis in a patient undergoing chemotherapy for Hodgkin lymphoma: diagnostic challenges and therapeutic dilemmas.

Background: Infective endocarditis (IE) in oncology patients represents a clinical challenge due to overlapping risk factors, diagnostic complexities, and treatment dilemmas, particularly in patients undergoing chemotherapy. We present a case that underscores the diagnostic difficulties distinguishing between IE and catheter-related right atrial thrombosis, emphasizing decision-making complexities regarding chemotherapy interruption. Case summary: A 29-year-old female with known Stage III Ab Hodgkin lymphoma, previously treated with chemotherapy and recent reimplantation of a port-a-cath presented with a 1-week history of fever, was diagnosed with febrile aplasia and treated with broad-spectrum antibiotic therapy. Initial two sets of blood cultures were negative. Transthoracic echocardiography demonstrated a mobile mass attached to the lateral tricuspid annulus within the right atrium. Thoraco-abdominopelvic computed tomography revealed distal pulmonary embolism. After 2 weeks of antibiotic and curative anticoagulant, complete resolution of intracardiac mass made the diagnosis of CRAT more likely and multidisciplinary team decided on discontinuation of antibiotic, continuation of anticoagulant, and resumption of chemotherapy, which was suspended for 2 weeks following suspicion of IE. Discussion: In the initial management of an intracardiac mass in the context of scheduled chemotherapy, two primary diagnostic hypotheses arise: infectious endocarditis and intracardiac thrombus. Ultimately, interdisciplinary consultation with cardiovascular infectious disease experts suggested a thrombotic lesion associated with abnormal jet flow supported by the absence of clinical and biological signs of infection. Prompt discontinuation of antibiotics, initiation of appropriate anticoagulation therapy, and close monitoring enabled safe resumption of chemotherapy.