[Aneurysmal bone cyst: A rare cause of orbital disease].

Aneurysmal bone cyst is a rare benign bone neoplasm of unknown cause. The most commonly affected anatomical sites are the vertebral column and long bones. We report two uncommon cases of primary orbital aneurysmal bone cyst presenting as an acute orbital compartment syndrome due to subperiosteal hemorrhage. Case 1 is a 45-year-old woman. Imaging studies revealed a small cystic frontal bone tumour associated with a subperiosteal hematoma. The patient achieved full visual recovery after drainage of the hematoma, with no recurrence after treatment. Case 2 is a 74-year-old woman whose visual acuity was light perception due to severe papilledema. Imaging studies of the orbit revealed a large cystic frontal bone tumor associated with a subperiosteal hematoma causing globe and optic nerve compression. Preoperative arteriography showed a moderate vascular blush. Drainage of the hematoma was performed. A local recurrence with hematoma formation occurred two years after the surgery.