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.