Aneurysmal bone cyst of the orbit associated with fibrous dysplasia.

Aneurysmal bone cyst is a rare but recognized osseous lesion of the orbit. We report the presentation, treatment, and postoperative course of an orbital aneurysmal bone cyst in a patient with McCune-Albright syndrome. To our knowledge, this report represents the first description of aneurysmal bone cyst of the orbit in a patient with fibrous dysplasia. Although visual loss in patients with fibrous dysplasia is most commonly due to narrowing of the optic canal, aneurysmal bone cyst should be considered in a patient with fibrous dysplasia who presents with decreasing vision in the face of a rapidly expanding orbital mass. The treatment in this case was drainage and debridement with prompt resolution. Although not necessary in this case, an alternative treatment includes packing with bone chips. Radiation is usually avoided because of the risk of iatrogenically induced sarcoma.