[Report of a case of intraosseous meningioma].

Cases of intraosseous meningioma appear to be very rare. In the present paper, we report such a case and discuss its etiological histogenesis on the basis of a review of 26 cases previously reported. A 71-year-old female was admitted to our department because of a painless mass in the right parietal region. Neurological findings were normal. Plain skull radiograph showed a 6 X 5-cm osteolytic lesion in the right fronto-parietal bone. CT scan demonstrated this lesion as a mass showing homogeneous enhancement with contrast medium. A right common carotid angiogram showed an avascular area in the parietal region and no tumor stain. The tumor, which was partly attached to the underlying dura, was totally removed surgically, and the postoperative course was uneventful. Histological examination of the specimen revealed fibroblastic meningioma, which was limited only to the outer membrane of the dura. The inner membrane was intact and free of tumor invasion. The histogenesis of intraosseous meningioma is still controversial but the following theories seem to be widely accepted: (1) The tumor arises from a part of the dura which has become trapped in a suture during embryological development. (2) The tumor arises from a part of the dura which has become trapped in a suture due to pressure on the head during delivery. (3) The tumor arises from a part of the dura which has become trapped in the bone due to trauma. (4) The dura which has become trapped in a suture during embryological development may undergo neoplastic change following traumatic stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)