A case of hip joint septic arthritis due to haematogenous infection, which was misdiagnosed sternoclavicular joint septic arthritis as SAPHO syndrome.

Anterior chest pain associated with sternoclavicular arthritis has been considered a symptom specific to SAPHO syndrome. Differentiating aseptic arthritis of the SAPHO syndrome from infectious sternoclavicular joint (SCJ) arthritis is often difficult. We reported a 55-year-old woman with left hip joint and right SCJ pain. Diagnosis and treatment were delayed because she was misdiagnosed with SAPHO syndrome, and haematogenous infection spread to the hip joint septic arthritis. She was diagnosed promptly after presenting to our hospital and underwent early debridement, and her hip joint and SCJ was found to have almost no dysfunction. Differentiation between sternoclavicular arthritis of the SAPHO syndrome and sternoclavicular septic arthritis is clinically important and requires careful attention.