Beyond the expected: a supratentorial ependymoma imitating a meningioma.

Background: Supratentorial ependymomas are rare tumors, particularly in adults, and can present similarly to more common extra-axial masses like meningiomas on imaging. Differentiating between these lesions is crucial for appropriate management.

Methods: A 16-year-old girl presented with a 1.5-year history of headaches, occasional blurring of vision, and a recent seizure. MRI revealed a 4.7 × 4.0 × 6.9 cm dural-based, extra-axial lesion in the left parietal-temporal region, initially presumed to be a meningioma. The patient underwent a neuronavigation-guided craniotomy with excision of the lesion. Intraoperative findings described a soft, vascular, solid-cystic extra-axial mass, which was initially diagnosed as a meningioma based on preoperative imaging but later confirmed to be a supratentorial ependymoma, ZFTA fusion-positive, CNS WHO grade 3, through histopathological and molecular analysis. Postoperatively, the patient showed no neurological deficits, and a residual tumor was identified on follow-up imaging.

Conclusions: This case illustrates the diagnostic challenge posed by the rare presentation of supratentorial, extra-axial ependymomas mimicking meningiomas. Although meningiomas are the most common extra-axial intracranial tumors, some radiological features such as cystic appearance and multiloculation on imaging should raise suspicion for ependymoma or other mimics. However, a definitive diagnosis can only be made through histopathological examination. Conclusions: Supratentorial, extra-axial masses are often misdiagnosed as meningiomas. Such ependymomas can closely resemble meningiomas on imaging. This case underscores the importance of maintaining a broad differential diagnosis for extra-axial masses and highlights the role of certain radiological features that can help with accurate diagnosis or at least raise suspicion of meningioma mimics.