Tanycytic ependymoma of the spinal cord. Case report and review of the literature.

OBJECTIVE AND IMPORTANCE We report a rare case of the tanycytic variant of intramedullary ependymoma. Tanycytes are the common progenitor cells of both ependymal cells and astrocytes. These particular elongate unipolar and bipolar ependymal cells extend from the ventricular lumen to the surface of the nervous system. It is extremely important, in terms of both management and prognosis, to distinguish intramedullary tanycytic ependymomas from intramedullary astrocytomas although a correct histological diagnosis may be difficult since tanycytes resemble astrocytes. CASE REPORT A 39-year-old woman underwent surgical treatment for a cervical intramedullary tumor in our department. Although pathological examination of frozen sections was suggestive of low-grade astrocytoma, the definitive histological diagnosis was "tanycytic" ependymoma, a tumor characterized by poor cellularity, elongated elements mixed with fibrillary components, rare pseudo-rosettes and mixed astro-ependymal aspects. Since a complete resection was performed at surgery, no further treatment was proposed. After a follow-up period of two years the patient is free from recurrence. CONCLUSION Tanycytic ependymomas should be managed in the same way as "ordinary" ependymomas, since there is no current evidence suggesting that these morphologically distinct tumors differ in terms of biological behavior. Increased awareness of this transitional form of intramedullary ependymoma among neurosurgeons and pathologists may avoid incorrect surgical approaches and postoperative treatment.