Synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome with cranial bone involvement: Case report and literature review

Abstract Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare autoimmune inflammatory disease characterized by osteoarticular and dermatological manifestations. The most common osteoarticular manifestations involve the anterior chest wall, axial skeleton, and long bones. Cranial bone involvement is less reported in SAPHO syndrome. We herein present three cases of SAPHO syndrome with cranial bone involvement, and review the previous literature on similar manifestations. It was revealed that SAPHO syndrome could lead to cranial bone involvement, which could involve the dura mater, leading to hypertrophic pachymeningitis, but the outcome is usually good. Janus kinase inhibitors may be a potential treatment option.