A 22-year-old female first presented with a fibrillary astrocytoma in the left temporal region manifesting as complex partial seizure. She underwent left temporal craniotomy to remove the tumor. Surgery was uneventful, but she began to experience a blocked feeling in the left ear after surgery. Computed tomography (CT) obtained 3 weeks after surgery revealed persistent extradural air collection, which developed into an enlarged extradural air mass on follow-up CT obtained 8 months after surgery. She underwent additional surgery for obliteration of the pneumatocele by sealing the mastoidal fenestration with abdominal fat. She reported resolution of the symptom postoperatively. Extradural pneumatocele following temporal craniotomy is extremely rare, but is a possible surgical complication of opening of the mastoid sinuses.