Purpose  To describe the clinical features of leber hereditary optic neuropathy (LHON) associated with fibrous dysplasia of bone in a boy.
Method  case report.
Result  A 16-year-old boy was referred to department of ophthalmology, first affiliated hospital of Guangxi Medical University, in July 2010. He presented with complaints of painless diminution of vision in both eyes for 2 months. There was a history of right femoral fracture surgeries in February 2010 and right humerus fractures in 2005. On examination, his visual acuity was counting fingers at 20cm in the right eye and at 40cm in left eye. Both pupils reacted sluggishly to light. The findings on slit-lamp examination and funduscopy were unremarkable in both eyes after pupillary dilation. Computed Tomography (CT) scan of the skull. and orbit revealed that the bilateral optic canals were narrowed and the right optic canal was suppressed mildly, and that bone fibres of right frontal bone, temporal bone, parietal bone, occipital bone and left temporal bone and sphenoid bone were proliferating abnomally. Blood Biochemistry showed alkaline phosphatase was high: 522u/L (reference range: 40-150u/L). A diagnosis of bilateral retrobulbar neuritis was made, and the boy was treated with steroids: intravenous methylprednisolone 500 mg in 1 dose for 6 days, followed by 250 mg in 1 dose for 3 days, then 40 mg of oral prednisolone. But had no effective improvement of vision. He was referred to Zhongshan Ophathalmic Center to exam, LHON mutations and reveal a mutation at position 11778 in mitochondrial DNA. This finding demonstrated a diagnosis of Leber hereditary optic neuropathy.
Conclusion  LHON should be remembered in the differential diagnosis in fibrous dysplasia patients with blurred vision.