Kai Shen, Cheng-Lu Yang, Geng Yin, Qi-Bing Xie

To the Editor: SAPHO syndrome is a heterogeneous disorder characterized by synovitis, acne, pustulosis, hyperostosis, and osteitis. Its diagnosis can be difficult if there are no typical skin manifestations. We reported a case of SAPHO syndrome which also fulfills the current diagnostic criteria, for ankylosing spondylitis (AS).

A 62-year-old Chinese female patient was evaluated for her bilaterally swelling sternoclavicular joints in our center. She had a 30-year history of nonprogressive lower back pain and spinal stiffness without debilitating motion limitation of the spine and was once diagnosed of AS in our center according to the documented human leukocyte antigen B27 (HLA-B27) positivity. Ten years ago, she began to develop episodic pain in her sternoclavicular area and bilateral shoulders. Localized reddening and tenderness were noticed over her sternoclavicular joints and the medial clavicular areas during those episodes. Her pain could also be mitigated by oral meloxicam, and her daily activity was not affected.

Physical examination showed enlarged sternocostoclavicular joints and deformed shoulders. Motion range of her hip joint, spine, and chest wall appeared normal. No acne or pustulosis-like rashes were noted. Laboratory assays revealed slightly elevated C-reactive protein at 20 ng/ml; erythrocyte sediment rate rose to 50 mm/h; spinal X-ray demonstrated wide-spread osteosclerosis, vertebral erosion, and multilevel bony bridging formation and marginal syndesmophytes [Figure 1]a. Chest computerized tomography (CT) revealed fusing destruction of her sternocostoclavicular joints with obvious hyperostosis [Figure 1]b. Pelvic CT showed obvious joint space narrowing, osteosclerosis and erosion of bilateral sacroiliac joints [Figure 1]c. Her scintigraphic bone scanning showed increased uptake in the sternoclavicular joint, sternum, and bilateral clavicles forming "bullhead sign". Finally, this patient was treated by oral meloxicam and thalidomide along with yearly infusion of zoledronate. No relapse of joint pain was reported in 6 months follow-up.