Neuro-ophthalmic presentation of leptomeningeal metastasis of thymoma: a case report

Introduction: Leptomeningeal disease (LMD) of the brain and spinal cord can present with visual loss or diplopia. Although LMD can occur in many forms of neoplasia, thymoma-related LMD is exceedingly rare. Patient presentation: A 53-year-old Hispanic male with a history of chest pain, weight loss, and night sweats was diagnosed with stage 4 thymoma with lung and pleural metastasis. He received chemotherapy for metastatic thymoma. Few months later, patient presented with severe right-sided facial pain and lip numbness, ptosis and double vision. Primary diagnosis: The patient was diagnosed with multiple cranial and spinal nerve involvement due to thymomatous LMD, confirmed on magnetic resonance imaging and lumbar puncture. Conclusion and importance: LMD is a rare presentation of a malignant thymoma. Current guidelines for thymoma management emphasize the importance of staging imaging to rule out distant metastasis. Our case highlights the importance of a head-to-mid-thigh positron emission tomography (PET) scan in patients with known metastatic thymomas, with multiple PET scans, if possible, at regular intervals, owing to the aggressive nature of metastatic thymomas. Clinicians should be aware of the neoplastic (e.g., metastatic disease and LMD) and paraneoplastic (e.g., thymoma-related myasthenia gravis) neuro-ophthalmic presentations of thymoma.