A benign bone condition in which orbital bone is slowly replaced by fibrous tissue and expands — reshaping the orbit, pushing the eye forward, and occasionally threatening the optic nerve.
Medically reviewed by EyePlastics Medical Editorial BoardASOPRS oculoplastic surgeonsLast updated June 2026
Fibrous dysplasia is a benign, slowly progressive bone condition in which normal bone is replaced by fibrous tissue and immature, poorly formed woven bone. When it involves the bones around the eye, the affected bone gradually expands and thickens, reshaping the orbit and the surrounding face. It most often appears in childhood or adolescence and tends to stabilize after skeletal maturity, although it can remain active into adulthood.

Monostotic vs. polyostotic. Fibrous dysplasia may affect a single bone (monostotic — the most common form) or several bones (polyostotic). The polyostotic form can be part of McCune–Albright syndrome, which also includes café-au-lait skin patches and hormonal (endocrine) overactivity such as precocious puberty.
Because the bone enlarges very slowly, the changes are usually painless and develop over years. Orbital involvement produces signs that reflect the expanding bone crowding the orbit and its structures:


CT scanning is the key investigation. Fibrous dysplasia has a characteristic hazy, “ground-glass” appearance where the normal bone has been replaced, together with expansion and thickening of the affected bone. This appearance, combined with the clinical picture, usually makes the diagnosis without the need for biopsy.

Management is guided by symptoms and by whether the disease is active or stable.
Radiation therapy is contraindicated. Irradiating fibrous dysplasia does not help and significantly increases the small risk of malignant transformation. Spontaneous malignant change is otherwise rare (well under 1%).
Fibrous dysplasia is one of several conditions that enlarge the orbit and push the eye forward. For the broader work-up of orbital masses see Orbital Tumors; for surgical reduction of orbital volume see Orbital Decompression.
Connect with a board-certified oculoplastic surgeon who specializes in fibrous dysplasia of the orbit.
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