Step 1 First Aid Rapid Practice Test

Meningioma is classically benign in adults with supratentorial tumors. These lesions arise from arachnoid cap cells and grow on the dura as extra-axial, well-circumscribed masses. They are usually WHO grade I, slow-growing, and tend to compress adjacent brain tissue without invading it, which is why they have a favorable prognosis with complete surgical resection. Imaging often shows a dural-based mass with a characteristic dural tail. Metastases to the brain are not primary tumors and can be multiple with variable aggressiveness, so they don’t fit the typical benign, solitary, extra-axial pattern. Glioblastoma multiforme is a highly malignant, infiltrative astrocytoma with necrosis and a poor prognosis. Schwannomas are benign nerve sheath tumors, but they most commonly involve the cranial nerves in the cerebellopontine angle (infratentorial SAMPLEregion) rather than presenting as a classic supratentorial benign tumor.