Meningioma mimicking an intraparenchymal cystic tumor

Area of Science:

• Neurosurgery
• Neuropathology
• Neuroradiology

Background:

• Meningiomas are typically dural-based tumors, but cystic variants with mural nodules are uncommon.
• These rare presentations can be mistaken for intraparenchymal cystic neoplasms on imaging.
• Accurate preoperative diagnosis is crucial for appropriate surgical planning and patient management.

Observation:

• A 64-year-old woman presented with a left temporal lobe cystic lesion and enhancing mural nodule, associated with peritumoral brain edema.
• Initial differential diagnoses included low-grade gliomas and hemangioblastoma.
• Intraoperative findings confirmed an extraparenchymal tumor with a thin membrane and yellowish cystic fluid.

Findings:

• Pathological examination confirmed the diagnosis of microcystic meningioma, WHO grade I.
• The imaging characteristics mimicked those of intraparenchymal tumors like hemangioblastoma and pleomorphic xanthoastrocytoma.
• Gross total resection was successfully achieved via a temporal surgical approach.

Implications:

• This case underscores the necessity of including meningioma in the differential diagnosis for cystic brain lesions with mural nodules.
• Recognizing this rare presentation can prevent misdiagnosis and guide neurosurgical interventions.
• Further awareness of cystic meningioma subtypes can improve diagnostic accuracy in neuro-oncology.