Fibrous Dysplasia

Fibrous dysplasia can present as monostotic (single bone) or polyostotic (multiple bones) involvement. The monostotic form is more common and often affects the ribs, femur, tibia, or craniofacial bones.
It typically appears in children and young adults and may be discovered incidentally or present with pain, swelling, deformity (e.g., shepherd’s crook deformity in the femur), or pathologic fractures.
Radiographs reveal a characteristic “ground-glass” appearance with cortical thinning and bone expansion.
Histologically, the lesion consists of irregular trabeculae of woven bone ("Chinese characters") without osteoblastic rimming.
Treatment is usually conservative for asymptomatic cases. Surgical intervention (e.g., curettage, grafting, internal fixation) is considered for symptomatic lesions or deformity.
Fibrous dysplasia can be associated with McCune-Albright syndrome (with café-au-lait spots and endocrine abnormalities) in polyostotic forms.