Ependymoma occurring at the cerebellopontine (CP) angle is an extremely uncommon sight and poses diagnostic and management dilemmas to neurosurgeons, radiologists, and neuropathologists alike. Moreover, the presence of extensive chondro-osseous metaplastic elements in ependymomas is an exceptionally infrequent histopathological manifestation. However, due to the seldom-seen nature of this histomorphological feature, there is no definite consensus regarding its etiopathogenesis and clinical consequences, and there is an extreme scarcity of literature elucidating its clinicopathological spectrum and prognostic significance. Herein, we illustrate an intriguing clinical tale of a 7-year-old male child with posterior fossa ependymoma, central nervous system (CNS) World Health Organization (WHO) grade 3, arising at the right CP angle and masquerading as a vestibular schwannoma, which in itself is a rare presentation, and additionally, exhibiting extensive chondro-osseous metaplasia, which is a very uncommon histomorphological observation. To the best of the authors' knowledge and after a comprehensive literature search, the coexistence of these two rare observations has merely been described once in international literature. This case sheds light on and highlights the importance of keeping ependymoma as a possible differential while coming across CP angle space-occupying lesions. They should be diligently distinguished from schwannomas and other masqueraders that typically occur at this site, as they have diverse management and follow-up protocols, with varying prognostic outcomes for the patients. Moreover, this case also unravels and details the clinicopathological characteristics of a scarcely described feature of chondro-osseous metaplasia in ependymomas.

Written informed consent was taken from the patient's guardian to participate in this study and for the publication of any potentially identifiable images or data included in this article. Ethical review and approval are not required and are provided a waiver for the publication of case reports as per institutional requirements.

S.M. had a key role in the conceptualization, drafting, and revision of the manuscript and the collection, analysis, and interpretation of the data. S.S.S. had a major contribution to curation, analysis, interpretation of data, and drafting of the manuscript. S.K. had an important role in diagnosing the case, conceptualization, providing resources, and critically revising the manuscript for important intellectual content.

Received: 05 May 2024

Accepted: 17 June 2024

Accepted Manuscript online:
24 July 2024

Article published online:
29 August 2024

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