A Rare Case of Solitary Plasmacytoma Arising From the Sternum

Solitary plasmacytoma (SP) is characterized by an accumulation of neoplastic monoclonal plasma cells in a localized fashion, without evidence of multiple myeloma. It makes up <5% of all plasma cell neoplasms and is typically found in regions like the pelvis, ribs, vertebra, and spine. SP is classified into extramedullary plasmacytoma (EMP), which primarily affects soft tissues, and solitary bone plasmacytoma (SBP), which primarily affects the pelvis, ribs, vertebrae, and spine. We report a case of a 66-year-old man with sternal plasmacytoma presenting as chest pain. He was treated with radiation therapy. Here, we aim to describe the clinical features, diagnostic methods, treatment, and potential outcome in a patient with SBP.