PURPOSE: To describe and characterize the CT findings of the sternal masses. MATERIALS AND METHODS: We retrospectively reviewed the medical records, pathologic reports, and CT findings of 16 patients whose chest CT revealed sternal masses. Two primary tumors were found, namely chondrosar-comas. Twelve metastatic tumors had arisen were from lung cancer (n=4), breast cancer (n=3), hepatoma (n=2), osteosarcoma (n=1), carotid body paraganglioma (n=1), and immature sacrococcygeal teratoma (n=1). Others were Castleman's disease (n=1) and inflammatory pseudotumor (n=1). RESULTS: Chondrosarcomas were large expansile osteolytic masses showing a variable degree of cortical break-through and containing punctate chondroid calcifications. Most sternal metastases (83 %) were located in the manubrium and were accompanied by metastasis in other bones (83 %). Metastatic tumors were nonspecific osteolytic soft tissue masses showing homogeneous or inhomogeneous enhancement, except for those which arose from an osteosarcoma and a lung cancer, and showed osteoblastic lesions. Castleman's disease was seen as an ill-defined enhanced soft tissue mass involving the sternum and adjacent soft tissue. Inflammatory pseudotumor appeared as an infiltrating lesion around the sternoclavicular joint and was accompanied by sclerosis and the erosion of opposing sternal and clavicular ends. CONCLUSION: Most of the sternal masses are due to malignant neoplasms, among which metastatic tumors are more common than primary ones. Metastatic tumors affect the manubrium more commonly than the body portion, and most also affect other bones in the thorax. CT findings of metastatic tumors are non-specific and thus do not suggest their origin. Non-neoplastic masses are not readily differentiated from malignant tumors on the basis of CT findings alone and require pathological confirmation.