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

BACKGROUND: 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. CASE DESCRIPTION: 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. CONCLUSION: 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.