Case-based review: ependymomas in adults

Abstract

Ependymomas are rare primary central nervous system (CNS) tumors in adults. They occur most commonly in the spinal cord, and have classically been graded histologically into World Health Organization (WHO) grades I, II, or III based on the level of anaplasia. Recent data are showing that genetic heterogeneity occurs within the same histological subgroup and that ependymomas arising from different CNS locations have different molecular signatures. This has renewed interest in developing targeting therapies based on molecular profiles especially given the variable outcomes with radiation and the poor results with cytotoxic agents. In this paper, we present the case of a 46-year-old woman with a classic presentation of spinal cord ependymoma and discuss the current histopathological and molecular classification for ependymomas as well as current guidelines for patient management.

Keywords: adults; chemotherapy; ependymoma; radiation; surgery.

Fig. 1

Intramedullary Spinal Cord Ependymoma. A, Axial and C, sagittal T1-weighted postcontrast magnetic resonance images (MRIs) demonstrate a well-demarcated intramedullary enhancing lesion centered at the level of C6. B, Axial and D, sagittal T2-weighted MRIs show the mass to be hyperintense, with adjacent edema and a subtle T2 hyperintense cap along the inferior tumor margin (arrow).

Fig. 2

Myxopapillary Ependymoma. A, Sagittal T2-weighted magnetic resonance image (MRI) demonstrates a sausage-shaped hyperintense mass centered at the L2-3 interspace that displaces traversing cauda equina nerve roots. B, Postcontrast T1-weighted sagittal MRI demonstrates avid homogenous tumoral enhancement. C, An axial T2-weighted MRI shows the tumor filling the canal with lateral displacement and compression of nerve roots (arrow).

Fig. 3

Posterior Fossa Ependymoma. A, Axial T2-weighted magnetic resonance image (MRI) demonstrates a mass centered in the right cerebellopontine angle with extension through the foramen of Luschka into the fourth ventricle (arrow). B and C, Axial and coronal T1-weighed postcontrast MRIs demonstrate heterogeneous enhancement within the mass.

Fig. 4

Supratentorial Ependymoma. A, Axial computed tomography image demonstrates a heterogeneous, primarily hyperdense, right frontal mass. B, T1-weighted postcontrast magnetic resonance axial and D, coronal images (MRIs) show heterogeneous tumor enhancement. C, Axial T2-weighted MRI confirms the presence of a cystic space within the tumor, as well as peri-tumoral edema along the posteromedial aspect of the tumor (arrow). E, Coronal fluid-attenuated inversion recovery image suggests purely intraparenchymal tumor location, without extension to the ventricle.

Fig. 5

A, Gross features of ependymal tumors: Well-circumscribed, tan tumor, relatively homogenous on cross-section is here represented by a myxopapillary ependymoma attached to a nerve fascicle from cauda equina (specimen is from a different patient). B, For the patient presented here, resection of intramedullary tumor showed a World Health Organization (WHO) grade II ependymoma composed of a monomorphic neoplastic proliferation with perivascular anucleate zones (pseudorosettes) (arrows) (100×, scale = 100 μm). The tumor cells were bland, with round to oval nuclei. Detail, 400×, scale = 20 μm) showed glial fibrillary acidic protein positivity with strong pseudorosette accentuation (left inset, 100×, scale = 100 μm) and perinuclear, “dot-like” epithelial membrane antigen reactivity (right inset, 400×, scale = 20 μm). C, Anaplastic ependymoma, WHO grade III: Hypercellular ependymoma with pseudorosettes, foci of microvascular proliferation (yellow long arrows) and necrosis (bounded by short black arrows in C) (100×, scale = 100 μm). D, Anaplastic ependymoma, higher power: Hypercellularity, microvascular proliferation (red circles), and numerous mitotic figures (long yellow arrows) (200×, scale = 50 μm) (specimens showed in C and D are from different patients).

Fig. 6

Molecular Classification of Ependymal Tumors. EPN indicates ependymoma; MPE, myxopapillary ependymoma; PF, posterior fossa; SC, spinal cord; SE, subependymoma; ST, supratentorial.