‘Now You See It, Now You Don’t’: A Rare Case of Pulmonary Artery Occlusion and Circulatory Collapse Due to Intravascular Extension of a Renal Cell Carcinoma to the Right Heart With Tumour Embolisation

Abstract

Intravascular extension of renal cell carcinoma to the right heart via the inferior vena cava (IVC) occurs in <1% of cases. A 47-year-old male with a known history of an inoperable right renal cell carcinoma was referred to this institution with intravascular, intracardiac extension of the tumour. On routine transthoracic echocardiography (TTE), a large multi-loculated mass (measuring 28 mm × 10 mm) was seen arising from the IVC and extending into the right atrium. The tumour mass prolapsed from the right atrium, across the tricuspid valve, entering the right ventricle during diastole. There was near complete occlusion of the IVC, as demonstrated on two-dimensional assessment and colour flow Doppler. The patient was initially treated with chemotherapy and immunotherapy, so as to avoid cardiothoracic surgery in the setting of advanced malignancy. Unfortunately, the patient re-presented to the Emergency Department with syncope and was found to be in obstructive cardiogenic shock. On TTE, it was noticed that the mass in the right-sided cardiac chambers was absent. Tumour embolisation was suspected, and an urgent computed tomography pulmonary angiogram was performed. This confirmed that the left main pulmonary artery was completely occluded with the tumour thrombus obstructing all flow to his left lung. The patient was transferred for urgent cardiothoracic surgery, during which time the tumour was successfully excised and his pulmonary artery repaired. This rare case of intravascular, intracardiac extension of a right-sided renal cell carcinoma highlights the potential catastrophic complications of intracardiac malignancies.