Cystic degeneration in fibrous dysplasia of the jaws: a case report.

A case of nonspecific cystic degeneration complicating fibrous dysplasia of the mandible is presented. This condition is extremely rare in the jaw bones. The patient had a painless swelling of the right face measuring 10 cm in diameter, and there was no history of trauma. Radiographs showed a poorly defined, "ground glass" radiopaque lesion; a central well-defined cyst was confirmed by means of computed tomography. During surgery, a large cystic cavity with surrounding, soft fibrous bone that merged with the cortex was observed. Histologic examination showed a large non-epithelial-lined cystic cavity with a surrounding fibro-osseous lesion, which was consistent with a diagnosis of fibrous dysplasia.