A 19-year-old right-handed man suffered from seizures characterized by staring that lasted about 10 minutes and began at age 13 years. These seizures were initially well controlled with medications but became refractory, occurring three to five times per week. A computed tomographic scan at age 13 years revealed a densely calcified mass in the right frontal lobe with no detectable contrast enhancement. A second scan at age 18 years showed no significant change in the right frontal lobe mass. T1-weighted magnetic resonance imaging at that time showed an inhomogeneous mass in the right frontal lobe with a broad-based surface but no dural attachment (Fig 1). Foci of intense enhancement were seen on contrast magnetic resonance image. In T2-weighted images, low-signal areas corresponded to the calcification seen on computed tomography. Angiography showed evidence of an avascular mass; abnormal vessels and tumor blush were absent. Electroencephalography revealed an