Large bifrontal meningioma

42-year-old with pathologically proven grade 1 meningioma. Noncontrast axial CT (A) shows a large, radiodense bifrontal mass. On transverse axial T2-weighted MRI (B), the mass has homogeneous signal intensity and is surrounded by a thin T2-hyperintense "CSF cleft" (C, arrows). On coronal CT with bone windowing (D), there is faint hyperdensity along the midline floor of the anterior cranial fossa (arrowhead), consistent with hyperostosis. Postcontrast MRI in the coronal plane (E) demonstrates an intensely and homogeneously enhancing meningioma with an area of hypoenhancement (thick arrow) that corresponds to hyperostosis.