Benign osteoblastoma of the orbit.

Benign osteoblastoma is a rare lesion of the orbit--only five cases have been described previously. The usual location is in the vertebral column and to a lesser extent in the skull. Although it is an invasive lesion, recurrences have not been reported after en bloc excision. The authors report a 10-year-old boy who presented with upper lid swelling, proptosis, and hypophthalmia. A computed tomography (CT) scan showed a calcified mass in the superior orbit which had eroded through the roof, and magnetic resonance imaging (MRI) showed a well-circumscribed mass between the periorbita and dura. A transcranial approach was used to remove the tumor, and the roof reformed with polypropolene. He has been followed for 18 months without recurrence.