Right atrial thrombus in treatment-naive patient with an early-stage classical Hodgkin lymphoma: a case report and review of the literature

Patients with hematologic malignancies are at increased risk of thrombotic complications, which most commonly occur during chemotherapy or in association with central venous catheter placement. Thrombotic events detected before systemic treatment initiation are uncommon, and intracardiac thrombosis represents a rare and diagnostically challenging manifestation. We report the case of a 21-year-old woman with newly diagnosed classical Hodgkin lymphoma in whom an asymptomatic right atrial mass was identified during pre-treatment assessment, 13 days after peripherally inserted central catheter placement. Staging PET-CT showed increased FDG uptake in the right pericardiac region, raising concern for possible cardiac or pericardiac disease involvement. Transthoracic echocardiography revealed a multilobulated right atrial mass, while cardiac magnetic resonance imaging supported its thrombotic nature and showed no evidence of neoplastic infiltration. Anticoagulation therapy was initiated and subsequently optimized, allowing the patient to complete chemotherapy without thromboembolic or hemorrhagic complications. End-of-treatment PET-CT demonstrated complete metabolic response, and follow-up echocardiography showed progressive reduction of the intracardiac lesion. This case highlights the importance of multimodality imaging in the differential diagnosis of right atrial masses in patients with lymphoma and underscores the need to consider both malignancy-related hypercoagulability and catheter-associated mechanisms.