Supratentorial Cystic Meningioma Resembling Pilocytic Astrocytoma: A Case Series and Literature Review

Cystic meningioma is a rare subtype of meningioma. Various brain tumors may mimic cystic meningioma in imaging appearance. Herein, we reported a series of cases with cystic meningiomas primarily misdiagnosed as pilocytic astrocytoma due to a similar radiological appearance.Methods: This case-series study included 20 patients with cystic meningiomas admitted to the Ghaem Hospital, Mashhad, Iran, between 2012 and 2019. The findings of magnetic resonance imaging (MRI), computed tomography, and neurological examination were recorded preoperatively. All the patients underwent surgery, and biopsies were obtained, confirming the histopathological diagnosis of the tumor.Results: The patients’ mean age was 40.7±12.5 years, including 11 men and nine women. Most of the patients presented with headaches (50.0%), and hemiparesis (60.0%) was the most found in the neurological examination. All neuroimaging studies revealed solid-cystic supratentorial tumors, in which cysts were intratumoral, larger than solid components, and eccentric relative to them. Most of the cysts were located in the frontal lobe. The T2 weighted MR images’ signal intensity showed hypointense lesions in 25.0% of the cases; however, 45.0% of the patients were hyperintense and 30.0% of them were isointense to grey matter. After contrast injection, the tumor’s solid and periphery experienced a homogeneous enhancement. The most common histopathological finding was meningothelial cells (30.0%) followed by fibroblastic cells (25.0%).Conclusion: Cases with an initially diagnosed pilocytic astrocytoma in the imaging can turn out to show cystic meningioma after pathological assessments, which deserves clinicians’ notice.