A case of SAPHO syndrome: a DISH of radiological features to be considered

BACKGROUND: The acronym SAPHO stands for synovitis, acne, pustulosis, hyperostosis, and osteitis. It is a rare heterogenous disease with unknown etiology and a chronic relapsing and remitting course(1). Its skin and osteoarticular manifestations including palmoplantar pustulosis (PPP) and synovitis may be transient which further complicate the diagnosis. So, awareness about all features of the syndrome throughout the time seems mandatory for correct diagnosis and avoidance of unnecessary procedures. Case presentation. A case of SAPHO syndrome being reported in a middle-aged man who presented with bilateral PPP and exacerbation of back pain which developed shortly after covid-19 vaccine injection with a history of more than 20 years of inflammatory thoracic back pain and psoriasis vulgaris who initially had been worked up for metastatic bony lesions based on radiologic studies, irrespective of his skin lesions. The patient had good response to alendronate 70 mg weekly and celecoxib 200 mg BID without aggravation of existing skin lesions or new psoriatic lesions. CONCLUSION: This case report aims to inform rheumatologists and radiologists about various radiologic and dermatologic manifestations of SAPHO syndrome with emphasizing on taking into consideration of past and present skin lesions in the interpretation of the radiologic signs in order to prevent irrelevant procedures or hazardous imaging and to urge rheumatology societies to set up a SAPHO registry for future randomized controlled trials. Suggestion of PPP responsiveness to NSAIDs as a new potential diagnostic tool for SAPHO diagnosis is another goal. It also aims to point out the possible coexistence of SAPHO and SpA or DISH syndrome.