The coexistence of SAPHO syndrome and rheumatoid arthritis: A case report.

Rational: SAPHO (Synovitis-Acne-Pustulosis-Hyperstosis-Osteitis) syndrome is a rare disease featured by its dermatological and osteoarthritic disorders, the latter of which mainly affecting the anterior chest wall, spine, and sacroiliac joint. However, rheumatoid arthritis (RA) is a chronic autoimmune disease, mainly affecting the synovial tissue of small joints in hands and feet. Here, we present an extremely rare case diagnosed with both SAPHO syndrome and RA, with an onset interval of 10 years. So far, only 1 similar case has been reported in the English literature. Patient Concerns: In Sep 2015, a 59-year-old female patient presented to our hospital, complaining of refractory low back pain, left sternoclavicular joint pain, and palmoplanar pustulosis (PPP). In addition, RA had been diagnosed 10 years earlier in the patient, manifested as pain and swelling in bilateral hands and wrists, accompanied by morning stiffness, as well as positive serologic tests. Interventions: In our hospital, laboratory tests revealed elevated inflammatory markers, and imaging examinations of relevant sites showed specific osteoarthritic lesions for SAPHO syndrome. Diagnoses: These findings lead us to make an easy diagnosis of the coexistence of SAPHO syndrome and RA in this petient. Outcomes: Treatment with tripterygium wilfordii polyglycosidium and prednisone was introduced. Both dermatological and osteoarthritic symptoms improved during a 3-month follow-up. Symptoms of RA were successfully controlled with prednisone and leflunomide since 2005. Lessons: We present an extremely rare case diagnosed with both SAPHO syndrome and RA, with an onset interval of 10 years. With this case report, we want to draw attention to the diverse features of SAPHO syndrome.