Fibrous Dysplasia

Abstract

Fibrous dysplasia is a benign intramedullary fibro-osseous “dysplastic” noninherited bone lesion. The disorder may be monostotic or polyostotic. There is a slight female predominance. Monostotic lesions (75%) are more frequent in the second and third decades. Polyostotic lesions (25%) are more frequent in the first decade. Approximately 3% of patients with polyostotic lesions have association with McCune-Albright syndrome, with café au lait pigmentation of the skin and endocrine anomalies. Any bone may be affected. Monostotic and polyostotic forms arise more frequently in long bones (proximal femur, tibia, humerus), craniofacial bones—especially in the jaws (the maxilla is more frequently involved than the mandible)—and ribs. Roentgenologic appearances in monostotic or polyostotic form are similar. Centered, intramedullary, elongated lesions arise in the metaphysis or diaphysis of long bones. Epiphyseal location is uncommon while the growth plates are open. The lesion has a ground-glass–like or lytic appearance. Histologically, the lesion is composed of a bland proliferation of plump fibroblasts in a dense, collagenous, well-vascularized matrix. Within the fibrous tissue, a variable presence of discontinuous, immature, woven osteoid or bone trabeculae is typical, with flat or spindle-shaped osteoblasts rimming. Treatment for monostotic, asymptomatic lesions is observation; surgical treatment, curettage, grafting, or resection can be used in cases of pathological fracture or risk of fracture, or to correct deformities.

Eduardo Santini-Araujo was deceased at the time of publication.