Solitary plasmacytoma is a rare disorder that is similar to multiple myeloma. People with solitary plasmacytoma do not have myeloma cells in the bone marrow or throughout the body. Instead, they have a tumor composed of plasma cells that is restricted to a single area of the body. Usually, these tumors are in a bone but sometimes an organ.
At Memorial Sloan Kettering, our experts diagnose solitary plasmacytoma when a biopsy of the tumor detects the presence of plasma cells but additional tests do not reveal signs of multiple myeloma. We look for such signs as myeloma-associated proteins in the blood and urine, or myeloma cells in the bone marrow.
Solitary plasmacytoma of the bone can sometimes be cured with radiation therapy or surgery to destroy or remove the tumor. However, 70 percent of people with solitary plasmacytoma eventually develop multiple myeloma. They then need additional treatment, such as chemotherapy. This may possibly be combined with a stem cell transplant.
When this type of tumor develops in the lungs, throat, or other organs, it is called an extramedullary plasmacytoma. More than half of people with extramedullary plasmacytoma are cured with radiation therapy.