A case of cerebral infarction due to pleomorphic carcinoma of the lung

With the increase in endovascular treatment, reports of embolism other than thrombus are scattered, but intracranial tumorigenic embolism is rare and difficult to diagnose. Here, we describe a case of a tumorigenic embolism in a patient with lung cancer whose invasion into the vascular system was not detected on preoperative whole-body imaging. A 66-year-old man who was hospitalized to undergo radiotherapy for pulmonary carcinoma suddenly developed left hemiplegia. He exhibited atrial fibrillation, and emergent radiographic examination revealed a right middle cerebral artery occlusion. Urgent mechanical embolectomy was performed, with successful revascularization. The excised embolus had a unique morphology and was pathologically diagnosed as a cerebral embolism caused by pleomorphic pulmonary carcinoma. Tumor-derived cerebral embolism is extremely rare, but it is necessary to consider it as a potential source of embolism during differential diagnosis in patients with malignant tumors.