Giant Cell Ependymoma of Lateral Ventricle: Case Report, Literature Review, and Analysis of Prognostic Factors and Genetic Profile

Background

Giant cell ependymoma (GCE) is a rare primary central nervous system neoplasm. We report a case of GCE arising in the lateral ventricle.

Case Description

A 22-year-old female presented with generalized seizures. Magnetic resonance imaging demonstrated a diffuse, nonenhancing, multicystic mass centered in the atrium of the right lateral ventricle with extension throughout the frontal and temporal horns. An initial subtotal resection yielded the signature biphasic pattern of GCE. The dominant component contained pleomorphic, bizarre-appearing giant cells with low mitotic index, and a minor component comprised monomorphic, highly cellular, mitotically active cells that formed perivascular pseudorosettes. Array-comparative genomic hybridization showed copy number abnormalities consistent with chromosomal instability without evidence of RELA- or YAP1-fusion—features most often seen in posterior fossa ependymoma group B. Given expectedly poor radiation sensitivity, a second-look surgery was undertaken to minimize residual before proton beam radiotherapy.

Literature Review

Review of the literature identified 28 reported cases, with a median age of 34 and bimodal peaks at approximately 20 and 50 years of age, including 9 supratentorial, 5 infratentorial, and 15 spinal ependymomas. Two infratentorial cases involved the fourth ventricle; no cases arose from the third or lateral ventricles. Supratentorial tumors predominated in younger patients, whereas other locations were observed among older patients (21.6 vs. 46.3 years of age; P = 0.01). Cases with Ki-67 index ≥10% showed worse progression-free survival than those of <10% (P = 0.049).

Conclusion

Although rare, GCE should be considered in the differential of young patients with atypical intraventricular lesions, particularly given that extent of resection is associated with increased survival and GCE is thought to be radiation resistant.

Introduction

Ependymomas are primary central nervous system neoplasms thought to arise from ependymal cells lining the ventricular walls and central canal of the spinal cord. The 2016 World Health Organization Classification of Tumors of Central Nervous System recognizes 5 major ependymal tumor subtypes including (classic) ependymoma, anaplastic ependymoma, myxopapillary ependymoma, subependymoma, and RELA fusion-positive ependymoma. Classic ependymoma has 3 further variants: clear cell, papillary, and tanycytic ependymoma.¹ Uncommon variants are also mentioned but with minimal description because rarity has precluded comprehensive clinical, histopathologic, and genetic characterization. Ependymoma with widespread pleomorphic giant cells (giant cell ependymoma; GCE) is an exceedingly rare variant of ependymoma, reported in isolated cases throughout the neuraxis. We report an unusual case of GCE originating from within the lateral ventricle of a young female patient. Additionally, we report novel data regarding the genetic profile of this rare disease, with abnormal copy number findings suggesting intriguing similarities to 1 of the 3 posterior fossa ependymoma groups within the ependymoma genomic classification schema, PF-EPN-B.