[Fibrous dysplasia and osteofibrous dysplasia]

Fibrous and osteofibrous dysplasia are benign lesions of the bone involving single bones as monostotic or multiple bones as polyostotic forms. When the patient is in the growth phase, the lesions, which are usually asymptomatic initially, may lead to deformities with typical bowing of the proximal femur ("shepherd's crook") and fractures. It is important to recognize osteofibrous dysplasia of the tibia and fibula, where any surgical measures, even a small biopsy, may activate the process and cause the lesion to grow, although it may spontaneously rest around puberty. Polyostotic fibrous dysplasia may rarely be associated with areas of cutaneous pigmentation and endocrine disturbances, especially precocious puberty (McCune-Albright syndrome).