Snapshot A 55-year-old woman presents to the emergency department after an unprovoked seizure. Laboratory testing is unremarkable. CT head without contrast demonstrates an extra-axial mass. An MRI brain with and without contrast demonstrates a homogenous extra-axial gadolinium enhancing mass. Neurosurgery is consulted for surgical resection. Introduction Overview neoplasm arising from the meninges most are benign Epidemiology Incidence most common primary brain tumor Risk factors ionizing radiation etiology Associated conditions neurofibromatosis type 2 schwannomatosis multiple endocrine neoplasia type 1 Presentation Symptoms/physical exam determined by the location of the meningioma these tumors are slow growing and often are asymptomatic for example, parasagittal meningiomas compressing the motor strip results in bilateral leg weakness seizures seen in ~30% of cases obstructive hydrocephalus if growing in the posterior cranial fossa Imaging MRI brain with and without gadolinium indication imaging study of choice findings extra-axial and dural-based mass that has homogenous signal changes uniformally enhanced with gadolinium may have a dural tear CT head with and without contrast indication initial imaging study of choice in patients with an acute focal neurological deficit findings extra-axial and dural-based mass with smooth contours uniformally enhanced with contrast Studies Histopathology indication required to confirm the dagnosis and determine if the meningioma is benign or malignant classified according to the World Health Organization (WHO) schema WHO grade I is considered benign WHO grade II and III are more likely to result in invasive disease findings include spindle cells arranged in a whorled pattern psammoma bodies Differential Malignant brain neoplasm differentiating factors based on histological findings e.g., glioblastomas will have pleomorphic tumor cells surrounding a central area of necrosis Treatment Medical radiation therapy indication nonaccessible meningiomas that requires intervention in atypical or malignant meningiomas to achieve source control after resection Surgical resection indication if symptomatic, meningioma is infiltrating, or resulting in substantial surrounding edema lesion must be accessible to be removed Complications Hydrocephalus Seizure Prognosis WHO grade I carries a favorable prognosis