[Giant calcified meningioma after radiation therapy for previous ependymoma: a case report].

We presented a case of secondary giant meningioma with dense calcification (brain stone) after radiation therapy for primary ependymoma removed 25 years before. A 31-year-old man was referred to our hospital because of generalized convulsion. He had received extirpation of an ependymoma in the left frontoparietal region and postoperative radiation therapy 25 years before. Skull X-ray and CT revealed a giant brain stone in the left parietal region. It was totally removed en bloc. Photomicrograph of the specimen showed proliferation of arachnoid cell-like tumor cells in narrow spaces surrounded by marked calcified lesions which showed partial ossification. The etiology and therapy of this tumor were discussed.