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A 45-year-old man with chronic chest pain for 20 years was referred to our department. The pain was dull, intermittent, exacerbated by exertion, located in the middle of his chest, accompanied by tenderness and radiated to both of his shoulders. At the same time, pustules intermittently appeared on his palms and soles. His prior medical and family histories were unremarkable. He denied having back pain, diarrhoea and other joint pain. On examination, his sternocostoclavicular joint was tender. His palms and feet soles showed hyperkeratosis without active pustulosis (figure 1). The remainder of the physical examination was normal. Laboratory test results revealed slightly elevated C reactive protein levels (0.63 mg/dL; normal range <0.14 mg/dL) but with normal erythrocyte sedimentation rate (11 mm/hour; normal range 0–15 mm/hour). The results for serum autoantibodies and rheumatoid factor were negative. Chest CT without contrast revealed bilateral large and swelling clavicles. Chest MRI without contrast in diffusion-weighted imaging showed high intensity in his sternum. Bone scintigraphy revealed remarkable radionuclide accumulation in the sternocostoclavicular joint, consistent with SAPHO syndrome (figure 2). Bone biopsy presented fibrosis of the bone marrow cavity, consistent with chronic osteomyelitis. Tissue culture was negative for tuberculosis and bacteria. He was diagnosed with SAPHO syndrome. As non-steroidal anti-inflammatory drugs were not effective, he was started on disease-modifying antirheumatic drugs, which resulted in the resolution of his chest pain.
SAPHO syndrome is a specific type of inflammatory bone disorder with osteoarticular and dermatological manifestations, which was first described by Chamot et al.1 While the acronym SAPHO was originally proposed as syndrome acne pustulosis hyperostosis osteitis, the ‘S’ was changed to synovitis in the following year.2 It is generally deemed a rare condition, which may be because this entity is underdiagnosed.2 Its pathophysiology remains unclear,3 but some authors thought that Propionibacterium acnes contributes to the development of SAPHO syndrome.2
The diagnosis of SAPHO syndrome is based on history, characteristic imaging test results and skin manifestations. SAPHO syndrome is a diagnosis of exclusion, especially necessitating to rule out septic ostemomyelitis and bone neoplasms.4 The osteoarticular involvement is gradual in onset, most commonly affecting anterior the chest wall (65%–90%) and followed by spine (~30%).2 Two of the common osteoarticular manifestations are hyperostosis and osteitis. Skin lesions are the key diagnostic clues for SAPHO syndrome, but they may occur years earlier or later.2 According to a case review, the cutaneous manifestations appear within an interval of 2 years before or after the onset of osteoarticular involvement in 70% of cases.2 The skin lesions are not essential for the diagnosis.5 The most common skin lesion is palmoplantar pustulosis, representing 50%–75% of all dermatological manifestations.2
Current treatments for SAPHO syndrome include non-steroidal anti-inflammatory drugs and analgesics. However, no randomised controlled clinical trials have been conducted due to its rarity. Systemic corticosteroids, disease-modifying antirheumatic drugs, biological agents targeting tumour necrosis factor alpha and IL-1, and bisphosphonates have been reported to be beneficial in some cases of SAPHO syndrome.2
I was relieved to know the cause of my pain.
SAPHO syndrome is common; however, chronic chest pain is an important differential diagnosis.
Palmoplantar pustulosis is one of the key cutaneous manifestations in SAPHO syndrome.
It is important to obtain carefully the history of cutaneous manifestations when diagnosing SAPHO syndrome.
Contributors All authors conceived the study concept and study design. TH and SK performed complication and synthesis of the data. TH and SK carried out statistical analyses. TS supervised the research project. All authors participated in interpretation of the results and writing of the report, and approved the final version.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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