Object: Fibrous dysplasia (FD) is a common osseous tumor that may affect the craniofacial skeleton. Cyst degeneration may occur within an existing FD lesion, manifesting as acute clinical deterioration. Because existing reports of this entity are limited, the object of this study was to describe the presentation and management of cyst degeneration in a relatively large series of patients.
Methods: For nine patients who were treated for cyst degeneration of craniofacial FD the following data were reviewed: demographic factors, clinical presentation, tumor type, computed tomography (CT) findings, surgical management, intraoperative findings, and histopathological findings.
Results: The mean age at tumor presentation was 14.9 years. Seven patients had received a diagnosis of FD before the acute changes of cyst degeneration occurred; this change occurred between I and 7 years after the initial diagnosis. The most common presenting symptoms were sudden mass enlargement (78% of patients) and pain (67%). No predisposing factor for cystic change was identified. Four patients presented with visual disturbance; blindness developed in two despite optic nerve decompression. Cyst degeneration occurred most commonly in the sphenoid and frontal bones. The cysts' appearance ranged from a simple lesion to aneurysmal bone cyst.
Conclusions: Cyst degeneration may occur spontaneously within the FD lesion years after the initial diagnosis. Evaluation with CT scanning remains effective in the diagnosis and monitoring of disease progression, and in treatment planning. Surgical intervention is indicated for patients with symptoms or functional impairment. Optimal management of this entity has been facilitated through careful collaboration between neurosurgeons and plastic surgeons.