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SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, and osteitis) is a seronegative spondylarthropathy. The term, introduced in 1987, describes a syndrome with various previous pseudonyms: multifocal recurrent osteomyelitis; arthritis with acne; and osteitis with pustulosis palmaris and plantaritis.1 Skeletal changes are commonest in the chest wall and skull involvement is uncommon.2,3 We present an unusual case of orbital SAPHO syndrome.
An 18 year old woman presented with 5 months’ retrobulbar pain, 2 weeks’ decreased vision, and a protruding appearance of her left eye. Previous medical history included thoracic spinal osteomyelitis aged 7. Her grandfather had suffered from a multifocal, recurrent osteomyelitis.
Visual acuity (VA) was 6/6 right eye and 6/9 left eye. There was 3 mm left axial proptosis with restricted elevation. Pupil reactions, colour vision, and funduscopy were normal in both eyes. CT scan showed lytic bone lesions and soft tissue swelling around the left anterior clinoid process and sphenoidal wings (fig 1A).
The episode was treated with oral NSAIDs. Three months later repeat CT showed the previously observed lytic areas had become sclerotic (fig 1B). A bone scan showed uptake in the left orbit and the area of the spine previously affected by osteomyelitis.
Ten months after the left sided presentation she developed headache for 2 days, diplopia, and decreased right vision. VA was 6/36 right eye, with 1 mm proptosis, 2 mm ptosis, and restricted right eye abduction. Pupil reactions, colour vision and funduscopy were normal. CT and MRI (figs 1C and 2) revealed multiple lytic areas around the right anterior clinoid process and sphenoidal wings. Prominence of the right superior orbital vein and optic nerve sheath indicated a degree of orbital apex syndrome. Treatment was with oral NSAIDS and pamidronate infusions. One month later VA was 6/9 right eye, and the other signs had resolved.
Eight months later biopsy of a left temporal bone lesion showed a mixture of fibrous tissue, foci of inflammation, and new bone formation. She has not developed any dermatological lesions.
Diagnosis of SAPHO syndrome depends on one of the following being present: (1) multifocal osteitis without skin manifestations; (2) sterile joint inflammation associated with pustules of palms or soles, psoriasis, acne, or hidradenitis; (3) sterile osteitis in presence of any skin manifestation.4
The pathogenesis is poorly understood. Fibrotic hyperostosis, a process which occurs alone in fibrous dysplasia, follows an initial acute osteolysis. Histologically a mixture of bone necrosis, new bone formation, fibrosis, and inflammation are seen.5 Links to HLA B27, spondyloarthropathy, Crohn’s disease, ulcerative colitis, Behçet’s disease,6 and Propionibacterium acnes have been suggested. Broad spectrum antibiotic treatment has not been shown to be effective.7
Radiologically, combinations of osteolysis, bone infarction-like lesions, and hyperostosis are seen.8 Differential diagnosis includes suppurative osteomyelitis, metastases, idiopathic orbital inflammation, and Langerhans cell histiocytosis. CT is indispensable in distinguishing these.
Pain is the commonest symptom, usually controlled with NSAIDs alone. Second line agents are pamidronate (anti-osteoclastic and anti-inflammatory) and corticosteroids. Third line agents include sulfasalazine, colchicines, and methotrexate.2,9
This case had the intriguing feature of bilateral optic canal involvement. Management with NSAIDS and pamidronate produced a good outcome.
Competing interests: none declared