A case of left middle cerebral artery occlusion diagnosed as malignant lung tumor embolus by mechanical thrombectomy

Objective: We report a rare case of lung cancer-associated tumor embolism that was diagnosed histopathologically with a thrombus collected via thrombectomy. Case: The patient was a 74-year-old man who was undergoing treatment of lung cancer at our hospital on an outpatient basis. The present illness was noted with sudden aphasia and right complete hemiplegia, for which he was transported to our hospital by an ambulance. MRI showed multiple small hyperintensities on DWI in regions including the left middle cerebral artery, bilateral cerebellum, and occipital lobes, and magnetic resonance angiography (MRA) revealed occlusion of the left MCA (M2). rt-PA was not used due to the risk for bleeding from the lung cancer lesion. Thrombectomy alone was performed, and recanalization of the thrombolysis in cerebral infarction (TICI) 2b was achieved with a stent retriever. The postoperative histopathological examination of the collected thrombus led to tumor emboli from squamous cell carcinoma of the lung. Neurological findings improved to NIHSS 1 one week after surgery; however, the patient died of progression of the primary disease on the 27th hospital day. Conclusion: Tumor embolism is a rare cause of cerebral embolism. Thrombi collected via thrombectomy from cancer patients with major artery occlusion should be evaluated histopathologically.