Teaching NeuroImages: Osteolytic intraosseous meningioma causing transcalvarial herniation

A 69-year-old man presented for focal seizures characterized by dysarthria, confusion, left hand paresthesia, and hemifacial contractions. He had a 3-year history of episodes of epigastric burning, followed by confusion, olfactory hallucinations, and déjà vu. Head CT scan showed a lytic lesion of right parietal bone (figure 1A). MRI highlighted transcalvarial herniation of precuneus gyrus (figure 1B), suggesting a congenital or posttraumatic skull defect or an osteolytic lesion. After surgical repair and excision of adjacent injured brain tissue, histopathology revealed osteolytic meningioma (figure 2). Intraosseous meningioma is extremely rare, may cause transcalvarial herniation by osteolysis,1 and can be revealed by histopathology.