A rare case of extra-intramedullary dorsal tanycitic ependymoma, radically removed with intraoperative neurophysiological monitoring

Introduction: Tanycitic dorsal extra and intramedullary ependymoma is a rare form of tumor. From the histological point of view, these tumors show several aspects that make difficult the differential diagnosis from schwannomas and pilocytic astrocytomas. Tanycytic variant, often occurs in the thoracic tract of the spinal cord, and it is constituted by tanycites, that are typical elongated and bipolar cells that give to the tumor fibrillary aspects. Tanycitic variant has been recently characterized as a variant of ependymoma, since the 2000 World Health Organization (WHO) system. Case presentation: A 57 years old woman presented with intractable back pain often radiating to the left leg. Neurological exam revealed mild weakness in left tight flexion. No sensory or sphincterial disturbances were present. A dorso-lumbar Magnetic Resonance Imaging (MRI)with contrast medium showed a well-demarked T12 intradural extramedullary lesion, suggestive for schwannoma. The tumor was radically removed, with an excellent neurological outcome, and was then characterized as a grade II tanycitic ependymoma. Conclusion: To differentiate the diagnosis between extramedullary ependymomas and schwannomas, meningiomas or astrocytomas is necessary a histopathological examination and a close follow up period is recommended since the tumor could evolve into higher grade. Neurophysiological monitoring is necessary for a satisfactory neurological outcome.