Fibrous dysplasia is an uncommon, nonmalignant bone disorder in which fibrous tissue and weakly woven trabeculae replace normal bone and bone marrow in single or multiple skeletal locations. Common sites are the long bones of the lower extremities (femur, tibia), arms, ribs, pelvis, and craniofacial bones. Fibrous dysplasia is typically diagnosed in adolescents or young adults in their 20s, with a slight male predominance.

It may be first observed incidentally during a bone scan. Signs and symptoms can include bone pain, swelling, pathologic fracture, bowing, leg-length discrepancy, or limping. Craniofacial fibrous dysplasia can interfere with vision, nasal airways, teeth alignment, and hearing. Facial asymmetry, swelling, and exophthalmos may be present. Some patients with this disease can have increased growth hormone.

Management involves observation and symptomatic pain treatment with analgesics. Orthopedic management can help prevent extensive bone damage and fragility. In the case of rapidly growing fibrous dysplasia, evaluation for the presence and management of endocrine disorders should ensue. Extensive craniofacial involvement may call for multidisciplinary monitoring of vision, hearing, and respiration. In severe cases, surgery may be considered.

The combination of polyostotic fibrous dysplasia, precocious puberty, and café-au-lait spots may point to McCune-Albright syndrome.