Solitary plasmacytoma
A solitary plasmacytoma is a plasma cell disorder that is characterised by the localised formation of a single mass (tumour) of monoclonal plasma cells. The plasma cells associated with plasmacytomas are malignant which means that plasmacytomas are considered cancerous. There is a risk that some patients with solitary plasmacytoma go on to develop myeloma at a later time.
There are two types of solitary plasmacytoma:
- Solitary Bone Plasmacytoma (SBP): the tumour exists within the bone
- Solitary Extramedullary Plasmacytoma (SEP): the tumour exists outside the bone
Solitary Bone Plasmacytoma (SBP)
A solitary bone or intramedullary plasmacytoma occurs when a patient has a single bone lesion, commonly in the spine or long bones of the arms and legs. Patients are diagnosed with SBP when they have a single lesion, less than 10% plasma cells in bone marrow from an uninvolved site and no other features of myeloma.
SBP has a high risk of progression to myeloma (approximately 50% within 5 years) and studies show that a significant number of patients with apparent SBP also have evidence of disease elsewhere, meaning their myeloma has otherwise been missed by the conventional tests. For this reason, it is mandatory that a whole-body MRI scan is performed in patients diagnosed with SPB. Many patients with apparent SBP who progress are likely to have had dispersed disease at presentation.
Treatment for SBP usually commonly involves radical radiotherapy given very intensely over several weeks and/or surgery to remove the tumour and sometimes to repair complications that have occurred as a result of the SBP. Occasionally in high-risk patients, chemotherapy may be an option.
Solitary Extramedullary Plasmacytoma (SEP)
A solitary extramedullary plasmacytoma commonly occurs in the tonsils or at the back of the nose, or in the digestive system, nervous system, bladder, thyroid gland, breasts, testicles, salivary glands and lymph nodes.
Unlike SBP, SEP has a lower risk of progression to myeloma. It is nearly always localised and has a high cure rate with radical radiotherapy treatment.