Intimal sarcoma of the pulmonary artery is a rare and potentially lethal tumor, the diagnosis of which is difficult and therefore frequently delayed. The clinical signs and symptoms are nonspecific, often mimicking chronic pulmonary thromboembolism (CPTE). We report the case of a 45-year-old male under treatment for CPTE associated with pulmonary arterial hypertension and chronic cor pulmonale. There was no response to treatment with anticoagulants and sildenafil. We emphasize the difficulties in diagnosing intimal sarcoma of the pulmonary artery, the need to investigate this neoplasm in the differential diagnosis of CPTE and the systematic use of criteria for the appropriate prescription of new medications for pulmonary artery hypertension.

Keywords: Pulmonary embolism; Hypertension, pulmonary; Hemangiosarcoma; Diagnosis, differential.