A 73-year-old patient underwent an extended pneumonectomy on the left side on account of a central malignant epitheloid leiomyoblastoma of the upper lobe. During this operation a tumor invasion of the pulmonary vein was discovered by chance. During the postoperative course the patient suffered from a tumor-caused morbus embolicus which led to his death. The autopsy showed cardiac metastasis. Four aspects are discussed: the morphology and biology of the malignant leiomyoblastoma, the incidence of cardiac metastases and their clinical diagnosis as well as the intraoperative embolism of tumor masses during lung resections.