The case-history of a 41-year-old man is reported. He was admitted because of the sudden development of left hemiparesis, loss of consciousness and increasingly deeper coma. The ECG demonstrated second-degree AV block with Wenkebach conduction or episodes with complete AV block. The colour Doppler ultrasound and cranial CT examination revealed occlusion of the right internal carotid artery and a cerebral infarct of the right hemisphere. Within 24 hours patient died from herniation of the brainstem. Postmortem examination revealed a pericardial neoplasm infiltrating both left and right atrium, AV junctional area, interventricular septum and right ventricle. The tumor tissue grew transmurally and protruded into the cavities of the heart. The right internal carotid artery was occluded by a tumor embolism. The histochemical and immunohistochemical results proved that the tumor was a primary malignant pericardial mesothelioma. This kind of cardiac tumor involving the AV node and mimicking stroke is very rare.