Neurosurgery Department, Hôpital Beaujon, Clichy, France.
Osteoid osteoma is a benign bone tumour which rarely occurs in the skull. A case of such a tumour in the posterior ethmoid region bulging into the anterior cranial fossa is reported in a 42-year-old woman who presented with intense frontal headaches. Excision of the tumour was performed through a subfrontal approach.