[A case of right heart failure: when it is not pulmonary embolism].

A 66-year-old patient with recent instrumental findings (echocardiogram, cardiac magnetic resonance imaging) of right ventricular failure was hospitalized due to worsening signs and symptoms of right heart failure, while waiting for diagnostic definition. Pulmonary computed tomography angiography revealed findings compatible with bilateral pulmonary thromboembolism involving the main pulmonary artery. Anticoagulant therapy was initiated with initial benefit, partial relief of symptoms, and moderate improvement in right ventricular function. However, after 4 weeks, the patient was readmitted for recurrence of heart failure and signs of low cardiac output. Echocardiography showed the presence of a conspicuous, mobile, isoechoic mass occupying much of the main pulmonary artery, once again suggestive of thrombosis. The patient underwent surgical thromboendoarterectomy; postoperatively, the procedure was complicated by severe refractory heart failure unresponsive to pharmacological treatments and mechanical support, leading to death in the subsequent days. Unexpectedly, histological analysis revealed a primary angiosarcoma of the endothelium of the main pulmonary artery, a very rare cause of pulmonary artery obstruction generally associated with worst prognosis and presenting with clinical features similar to pulmonary thromboembolism.