Meningioma

Meningiomas are extra-axial tumors typically attached to the dura and indent (rather than invade) the brain; imaging shows a 'dural tail' on contrast MRI. Histology shows spindle cells in whorls and laminated psammoma bodies (calcified concretions). They express estrogen and progesterone receptors, explaining female predominance and growth during pregnancy. NF2 gene (chromosome 22) loss is the most common genetic abnormality; also seen in neurofibromatosis type 2. Symptoms depend on location and include seizures and focal deficits; parasagittal location can cause leg weakness by compressing the motor cortex's medial homunculus. Treatment is surgical resection; usually WHO grade I.