Supratentorial clear cell ependymoma mimicking oligodendroglioma : case report and review of the literature

Abstract

Clear cell ependymomas (CCEs) are rare variants of ependymomas. Tumors show anaplastic histological features and behave as an aggressive manner. CCEs have a predilection for extraneural metastases and early recurrence, and they demonstrate characteristic radiographic features. These tumors should be radiologically and pathologically differentiated from oligodendrogliomas. On microscopic examination, CCEs are composed of sheets of cells and resemble oligodendroglioma. However, upon closer examination, the nature of CCEs can be detected earlier, resulting in prompt treatment of the tumor. Although we report only one case, we emphasize the importance of early diagnosis and treatment. Future description of more cases of these rare cancers is necessary to aid in their diagnosis and treatment.

Keywords: Clear cell; Ependymoma; Histology; Oligodendroglioma; Prognosis.

Fig. 1

Brain computed tomography image at pre-operation. A : Non enhancement image : 5 cm infiltrating mass in the right frontal lobe extending to the corpus callosum and the left frontal lobe. B : Enhancement image : diffuse enhancement of the tumor mass in both frontal lobes and genu and in the anterior body of the corpus callosum.

Fig. 2

Brain magnetic resonance imaging. A : T1-weighted image (T1WI) coronal. Multiple signal voids, internal cystic or necrotic portions within the right frontal lobe mass. B : T1WI axial. C : T2-weighted image (T2WI) axial. Increased signal intensity of peritumoral edema in both frontal lobes and in the posterior body of the corpus callosum. D : T1WI enhancement. Well enhanced tumor mass.

Fig. 3

Pathological findings. A : perivascular pseudorosettes. B : sheets of clear cells with rounded nuclei and perinuclear halos.

Fig. 4

Immunohistochemical staining. A : Tumor cells show positivity for GFAP (glial fibrillary acidic protein) antigen. B : EMA (epithelial membrane antigen) (-). C : CK (Cytokeratin ) (-). D : Ki-67=2%.

Fig. 5

Brain computed tomography image and magnetic resonance imaging (MRI). A : Postoperative status. B : Six months postoperatively with adjuvant radiologic therapy, 60 Gy. C : One-year follow-up brain MRI showing recurred tumor at the previously resected lesion.