Periorbital inflammation associated with craniofacial fibrous dysplasia: Report of three cases and review of the literature.

Fibrous dysplasia (FD) is a mosaic skeletal disorder in which the craniofacial bones are commonly affected. Normal structures are replaced by expansile, highly vascular, fibro-osseous tissue. The typical clinical course is a gradual, asymptomatic expansion of the osseous structures. However, in the periorbital region, even minor structural changes may cause functional impairment, such as diplopia and hyposmia. Furthermore, rapidly evolving secondary lesions, such as fluid-filled cysts, can sometimes develop. In the midface and periorbital regions, such acute change may be associated with severe pain, vision loss, and, signs of inflammation. Here we describe three patients with craniofacial FD who presented with recurrent episodes of periorbital inflammation mimicking orbital cellulitis. All presented with pain, edema, erythema, and warmth, with varying degrees of functional impairment. On imaging, all had cystic changes in the FD lesion, including two with aneurysmal bone cysts (ABCs). Two were initially diagnosed with periorbital cellulitis and treated with antibiotics; in two, the radiographic findings were misdiagnosed as osteomyelitis. Recurrent episodes were recognized as not infectious and effectively managed with corticosteroids. Given the vascular nature of FD and the association of ABCs, it is likely the findings in these patients represent inflammation associated with vascular leak in the relatively confined space of the tissues overlying the periorbital bones. Recognition of this entity can lead to more rapid and appropriate treatment.