SAPHO classically tends to present in young to middle-aged adults. Presentation in the pediatric population is not uncommon. There may be slightly higher female predilection 8.
Pathology
SAPHO and related conditions have three stages of progression, which are described as:
arthropathy of the sternoclavicular joint, osteitis of the medial end of the clavicle, first rib and sternum as well as hypertrophy of the costal cartilages
osteitis, hyperostosis and hypertrophy of the medial ends of the clavicles, sternum and upper ribs and ultimately ankylosis
Etiology
Many causes have been suggested with infectious etiology considerably favored. Propionibacterium acnes, an anaerobic saprophyte found in human skin, has been isolated from the biopsy specimens of bone and synovium 8.
Serology
HLAB27: may be positive in around 30% of patients 8
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Radiographic features
Plain radiograph
Plain radiograph is non-specific, but SAPHO syndrome can be suspected if present with the other clinical findings:
long bones: metaphyseal osteosclerosis and osteolysis5
Nuclear medicine
Increased uptake at bone scan centered on both sternocostoclavicular joints in the characteristic "bull's head" configuration.
Treatment and prognosis
Tends to be benign although patients may have recurrent bouts of attacks. Pamidronate therapy has been successfully trialed for symptom relief (especially in the pediatric population) 6.
3. Boutin RD, Resnick D. The SAPHO syndrome: an evolving concept for unifying several idiopathic disorders of bone and skin. AJR Am J Roentgenol. 1998;170 (3): 585-91. AJR Am J Roentgenol (citation) - Pubmed citation
4. Azouz EM, Jurik AG, Bernard C. Sternocostoclavicular hyperostosis in children: a report of eight cases. AJR Am J Roentgenol. 1998;171 (2): 461-6. AJR Am J Roentgenol (abstract) - Pubmed citation
6. Kerrison C, Davidson JE, Cleary AG et-al. Pamidronate in the treatment of childhood SAPHO syndrome. Rheumatology (Oxford). 2004;43 (10): 1246-51. doi:10.1093/rheumatology/keh295 - Pubmed citation6
7. Sweeney SA, Kumar VA, Tayar J et-al. Case 181: Synovitis Acne Pustulosis Hyperostosis Osteitis (SAPHO) Syndrome. Radiology. 2012;263 (2): 613-7. doi:10.1148/radiol.12101436 - Pubmed citation