AGGRESSIVE FIBROUS DYSPLASIA OF THE MAXILLARY SINUS

Fibrous dysplasia is usually a slowly progressive, benign disease that develops over several years and presents with deformity or mild sympt omatology. Five of 34 patients (ages 4-21 years), who were subsequentl y diagnosed histologically as having fibrous dysplasia of the maxillar y sinus, rapidly developed soft tissue masses of the malar region over a period of less than 4 months with accompanying pain (2 patients) an d nasal obstruction and exophthalmos (2 patients). Each was clinically suspected of having a sarcoma; two had been thought to have an '' ost eofibrosarcoma '' on initial biopsy at outside hospitals. After resect ion, all lesions developed regrowth. At histopathologic examination, b oth initial and recurrent masses proved to be typical fibrous dysplasi a with spicules of woven bone in cellular, sometimes vascular, fibrous tissue. No malignant degeneration was found. On conventional radiogra phy, aggressive fibrous dysplasia produced opacification and expansion of the maxillary sinus and apparent disruption of its wall with an as sociated soft tissue mass. Computed tomography (CT) demonstrated volum inous heterogeneous masses with ''ground glass appearance'', calcifica tions, areas of enhancement, low attenuation, cystic areas, and a thin ned, sometimes interrupted, maxillary wall. Despite the aggressive cli nical course for both initial and recurrent lesions, the CT findings o f a ''ground glass'' mass with calcifications surrounded by a maxillar y sinus wall, even if incomplete, can suggest the diagnosis of aggress ive fibrous dysplasia.