Isolated fibrous dysplasia of the zygomatic bone.

Fibrous dysplasia is a nonneoplastic, hamartomatous, developmental disease of the bone of obscure etiology. The disease is generally presented as a continuously growing, painless mass at late childhood. It is mostly seen in the maxilla and the mandible in facial skeleton. Involvement of the zygomatic bone is far rarer. Fibrous dysplasia of the zygomatic bone may cause orbital dystopia, diplopia, proptosis, loss of visual acuity, swelling, mass formation, or facial asymmetry. We present 2 cases of fibrous dysplasia with isolated zygomatic bone involvement.