Renal cell carcinoma (RCC) is one of the most lethal cancers and is frequently associated with tumor thrombus (TT), an intravascular extension of the tumor. Approximately 4% to 10% of RCC patients present with TT, which may involve the renal vein (10%–18%), the inferior vena cava (4%–23%), and, rarely, the right atrium (1%). These thrombi are usually associated with advanced tumors, often with distant metastases, and reflect an aggressive biology. Management is challenging, particularly in metastatic cases, with surgical resection being indicated in the absence of metastases. Anticoagulation remains controversial due to the neoplastic composition of TT. We report the case of a 51-year-old man with clear cell RCC and pulmonary and hepatic metastases, treated with pazopanib. The patient developed right heart failure and was diagnosed with extensive TT extending to the right atrium, identified by transthoracic echocardiography. At an advanced stage and with clinical deterioration, palliative care was chosen, and the patient died within a few weeks. The diagnosis of TT is crucial for defining prognosis and therapeutic strategies. Echocardiography, combined with advanced imaging techniques, plays a key role in differentiating TT from thromboembolism. This case highlights the importance of a multidisciplinary approach and technologicaladvances in the management of complex conditions such as TT, aiming at early diagnosis and reduction of complications.

João Pedro Perfeito Frigo is a cardiologist with specialized training in Echocardiography from the Clinical Hospital of the Federal University of Uberlândia (UFU). He completed his residency in Internal Medicine at Santa Casa de Misericórdia de Araguari and his residency in Cardiology at the Federal University of Triângulo Mineiro (UFTM), where he further developed expertise in cardiovascular diagnosis and treatment.