Myxopapillary ependymoma in the third ventricle area and sacral canal: dropped or retrograde metastasis?

Myxopapillary ependymoma (MPE) is a rare type of central nervous system neoplasm mostly located in the cauda equina and filum terminale regions. A previously healthy 22-year-old Chinese man presented with the first case of MPE in the third ventricle area and sacral canal initially manifesting as spinal cord compression. The patient was admitted with pain in the right lower extremity for 5 months and encopresis for 3 months. Magnetic resonance imaging of the lumbar spine revealed an intradural lesion at the S2 level. The patient accordingly underwent lumbar laminectomy surgery and gross total resection of the tumor. Shortly after surgery, a mass was found in the third ventricle. The patient subsequently underwent further craniotomy surgery, and the histopathological examination eventually revealed MPE. MPE usually undergoes intracranial retrograde metastasis, but we consider that our case was a dropped metastasis of the primary intracranial MPE. Neurosurgeons need to be aware of intracranial MPEs in patients with isolated spinal lesions, and long-term follow-up is important in patients who are diagnosed with MPE after surgical excision.