Introduction: Ependymoma metastasis occurs usually along with local recurrence within 7 years after the initial diagnosis. Later spinal metastasis without local recurrence after the surgical resection has been rarely reported in patients with low-grade ependymomas but not with high-grade ependymomas. Here, we present a case with autopsy revealing late extensive supratentorial metastasis of a fourth ventricle classic WHO grade II ependymoma with no local recurrence or spinal metastasis.
Methods: A 4-year-old boy underwent a gross total resection (GTR) of the fourth ventricle ependymoma and postoperative radiation therapy. Follow-up MRI showed no recurrence for the next 7 years, but a half year later, extra-axial tumors in the left cerebellopontine angle and right frontal lobe were observed. GTR of the left cerebellopontine angle ependymoma was performed, followed by additional radiation therapy.
Results: He was stable for the following 2 years before MRI revealed growth of the right frontal tumor and new lesions. GTR of the right frontal tumor demonstrated similar pathologic features of ependymoma. Despite chemotherapy, follow-up MRIs exhibited increasing numbers and sizes of supratentorial tumors but no infratentorial or spinal tumors. He died 15 years after the initial diagnosis. Postmortem brain examination confirmed the supratentorial subarachnoid dissemination with multifocal metastases of classic ependymomas but no recurrence at the infratentorial sites.
Conclusion: Our case study and literature review suggest that low-grade ependymomas under the current WHO classification have the risk of late metastasis. Therefore, long-term follow-up of the whole neuroaxis is more important for the patients with low-grade ependymomas even in the absence of local recurrence.