SAPHO Syndrome in a Patient with Breast Cancer Mimicking Bone Metastasis: A Case Report

Bone is the most common site to which breast cancer metastasizes (1). Bone represents the first site of metastasis for 26~50% of patients with metastatic breast cancer (2, 3). If hot uptake in a patient with breast cancer is noted on the bone scintigraphy, the possibility of bone metastasis should be considered. However, because metastatic arthritis rarely occurs and the costosternoclavicular region is not common site for metastasis, other possibility should be considered such as SAPHO syndrome; it is an acronym of syndrome of synovitis, acne, pustulosis, hyperostosis, and osteitis (4) and its diagnosis can be made on the base of the solely musculoskeletal system without even skin lesions. And the costosternoclavicular region is known to be typical site of it (4). So, if the sclerotic and hyperostotic bone change of costosternoclavicular region was incidentally found in early breast cancer patient, try to include the SAPHO syndrome as a possible differential diagnosis. Here, we present a patient with right breast cancer and incidentally found sclerotic and hyperostotic bony lesion of her left costosternoclavicular region, which was confirmed as chronic active inflammation without causative organism. INTRODUCTION