Spontaneous systemic tumor embolism caused by tumor invasion of pulmonary vein in a patient with advanced lung cancer.

We describe a 72-year-old man who presented with left hemiparesis due to acute cerebral infarction in the right fronto-temporal lobe. Three months prior to admission, he was hospitalized for right hemiparesis due to the acute cerebral infarction in the left anterior cerebral artery territory. To investigate the cause of his recurrent embolic event, a chest computed tomography scan and echocardiography were performed, which revealed advanced lung cancer invading contiguously through the pulmonary veins to the right main pulmonary artery and left atrium. Tumor embolism is a rare cause of stroke, occurring with primary or metastatic neoplasms of the lung. Echocardiography is a useful tool in patients with cerebral embolic episodes.