Study design: Spinal ependymoma is a benign central nervous system tumor described as an intramedullary lesion more frequently located at the conus medullaris. It has been described exceptionally in the literature as an intradural extramedullary tumor.
Objective: Presentation of an extremelly rare location and evolution of extremedullary ependymoma and discussion of its probable origin, differential diagnosis, treatment options, and follow-up.
Summary of background data: This case demonstrates an unusual location of a benign ependymal tumor in the extramedullary space with a total resection, which recurred in a lower level with a malignant transformation with the same extramedullary location.
Methods: The authors present the case of a 47-year-old woman with a subacute spinal cord dysfunction and an intradural extramedullary D2-D3 tumor mimicking meningioma or neurinoma. At surgery, an encapsulated intradural extramedullary mass was found, but neither dural attachment nor medullary infiltration was present.
Results: After complete resection, anatomic-pathologic studies confirmed that the lesion was a benign classic ependymoma. Good neurologic outcome was achieved, and no residual tumor was present at magnetic resonance imaging (MRI) control performed at 3 and 9 months later. One year after surgery, a new intradural extramedullary tumor was found at the D4 level without recurrence at D2. The patient was operated on again, but at this time the histologic study showed an anaplastic ependymoma with a proliferation index of 25% measured by Ki-67. Whole central nervous system radiotherapy was performed.
Conclusion: All of the previously reported cases of spinal intradural extramedullary ependymomas carried out a benign course. The case we are reporting is the first one in which malignant transformation occurred. This tumor should be taken into account in the differential diagnosis of intradural extramedullary lesions. Moreover, close follow-up is recommended for this unusual location of ependymomas.