A 14-year-old domestic shorthair cat was evaluated for a 3-month history of head pressing and circling. Neurological examination suggested a supratentorial problem, predominantly on the left side. An extradural mass extending from the rostral frontal lobes caudally to the level of the caudal aspect of the corpus callosum was found with magnetic resonance imaging. A bilateral rostrotentorial craniectomy combined with a frontal sinus craniectomy was performed for mass removal. A gamma-irradiated calvarial allograft was used to repair the calvarial defect. At 14 months following surgery, the cat had no neurological abnormalities, and the skull and facial appearance was normal.