Aneurysmal Bone Cyst of the Orbit

Aneurysmal bone cysts are uncommon benign, expansile, and lytic lesions that develop in childhood or early adulthood. An aneurysmal bone cyst usually occurs as a primary lesion. In one third of the cases reported in the literature, a preexisting condition or history of trauma is present. Pain and swelling are the main symptoms and usually last for as long as 6 months. Long bones are involved in more than half of the cases. Involvement of the spine and flat bones also has been reported (1, 2). Skull involvement is rare, occurring in less than 1% of all aneurysmal bone cysts (3). The orbit is much less frequently involved; a review of the literature revealed only 20 cases (3–7). Among them, we could find only two presentations with MR imaging findings, and these were not published in the radiologic literature (3, 4). We present CT and MR imaging findings in a case of aneurysmal bone cyst of the orbit that was confirmed by histopathologic analysis.