Extraneural Metastasis of Ependymoma in the Cauda Equina

We report a rare case of extraneural metastasis of spinal ependymoma that developed over a very long period. A 28-year-old man underwent surgery for ependymoma in the cauda equina. After he experienced three local recurrences and had undergone five operations, a lung metastasis occurred 46 years after the first operation. Although the tumor did not show the typical morphological malignancy, the maximum standard uptake value obtained by positron-emission tomography and the antigen Ki-67 labeling index demonstrated the tumor's active proliferative ability. One year after the last operation, the patient died of respiratory failure due to progressing lung metastases. The malignant behavior of spinal ependymomas is demonstrated in a case with long-term follow-up.