We present a magnetic resonance image of a 51-yearold female patient who presented with symptoms and signs of bilateral femoral artery embolism. An emergency embolectomy was performed, and histologic examination of the embolectomy specimens revealed metastatic adenocarcinoma. Further work-up revealed a tumor in the left atrium on echocardiogram, and a mass in the left upper lobe on chest x-ray. The primary malignancy was confirmed on computed tomography scan. A subsequent magnetic resonance imaging scan clearly demonstrated the primary tumor (Fig 1, T), with invasion of the left superior pulmonary vein (Fig 1, V) and extension into the left atrium (Fig 1, A). The patient was placed on heparin, but later developed intracranial hemorrhage from which she did not recover.Systemic tumor embolism is an uncommon event. The majority of cases are due to left atrial myxoma, which can embolize in almost half of the patients [1]. Although most malignant tumors spread by invading the blood vessels, such spread to distant sites is due to invasion of microvasculature in the form of microscopic aggregates or single cells. It is extremely rare, however, for a malignant tumor to cause a large enough embolism to result in clinically significant vascular compromise. The majority of cases of systemic malignant embolism reported in the literature have resulted from bronchogenic carcinoma [2][3][4][5][6]. Most of these occur either intraoperatively or in the immediate postoperative period [5,7,8]. Sudden intraoperative death has also been reported as owing to massive embolism of malignant tissue [9]. Embolization has been reported to occur from lung cancer, to cerebral, coronary, and mesenteric circulation; aorta; and extremity vessels [5]. Multiple simultaneous embolizations have also been reported. Spontaneous embolization to systemic circulation from bronchogenic carcinoma is even more uncommon, and only three previously published articles report this phenomenon. The proposed mechanism of systemic tumor embolization from lung cancer is invasion of pulmonary veins with or without invasion into the left atrium. Very rarely, a tumor could invade the venous circulation (eg, renal cell cancer growing into the inferior vena cava) and spread to the left heart through a patent foramen ovale, becoming a systemic tumor embolism.Little is known about what causes "spontaneous" embolization, but intraoperative manipulation is thought to release emboli from the tumor already invading the pulmonary veins in cases in which embolization occurs intraoperatively. Although it is not clearly known whether such spread can be prevented, a review from 1951 suggested early ligation of the pulmonary vein to prevent this phenomenon [10]. Another report recommended that if a tumor is palpated in the pulmonary vein, pulmonary resection should not be attempted, the patient should be placed on cardiopulmonary bypass, and the left atrium should be opened to remove the intracardiac portion of the tumor using pulmonary resection [7]. Finally, it was indicated that p...
