Supratentorial Clear Cell Ependymoma Mimicking Oligodendroglioma : Case Report and Review of the Literature

histologic subtypes, as well as significant differences between spinal cord tumors and brain tumors of the same histologic type 12) .Genetic heterogeneity has also been noted when comparing pediatric and adult tumors from the same location and with the same histology 4) .Ependymomas are difficult to diagnose because of this heterogenicity and because their appearances mimic those of other intracranial tumors.There are several primary CNS tumors that are similar in appearance to ependymomas.Predicting the prognosis of such a tumor is also difficult because ependymomas vary considerably both in their morphologic appearance and biological behavior 13) .Clear cell ependymoma (CCE) is an uncommon and diagnostically challenging variant which was first described by Kernohan in 1937 3,17) and was recognized by the World Health Organization (WHO) as a distinct entity in 1993 9) .CCE is characterized by sheets of uniform cells with rounded nuclei and perinuclear, clear halos.It may closely mimic several other tumors, including oligodendroglioma, central neurocytoma, hemangioblastoma, and metastatic renal cell carcinoma 5) .However, CCEs can be distinguished from other tumors by their classic ependymal rosettes and perivascular pseudorosettes.CCEs have a tendency to be aggressive despite therapy.It is important to distinguish this entity from others because the treatment and prognosis of each variant differ significantly.Immunohistochemical staining is known to be helpful for diagnosis.Here, we describe a patient with CCE and review the literature concerning radiological and pathological characteristics of and therapeutic implications for CCE.