Aneurysmal bone cyst of the orbit.

A 16-year-old girl presented with progressive, painless proptosis of the left eye. X-ray studies revealed an extensive lesion involving the left orbit, antrum, and middle cranial fossa. A biopsy confirmed the diagnosis of aneurysmal bone cyst, and the lesion was surgically excised. There has been no evidence of recurrence after three years. In a review of the literature, we were able to find only seven other cases of aneurysmal bone cyst involving the orbit.