Convexity meningioma: This is a coronal section through frontal lobe with a convexity meningioma. The slide demonstrates the extrinsic location of this neoplasm, with compression of underlying brain. The cortex beneath the tumor is not usually invaded, so that this tumor, if diagnosed sufficiently early, can usually be removed completely. Unfortunately, if not diagnosed, edema of the underlying hemisphere (right side of the photograph) ensues, with distortion and displacement of ventricles and midline structures.