If you have multiple myeloma, cancerous plasma cells divide and grow inside your bone marrow. Plasma cells are white blood cells that make antibodies. Antibodies are part of your immune system. They usually help defend your body against infection.
There are two main subtypes of multiple myeloma:
- Hyperdiploid (HMM). Myeloma cells have more chromosomes than normal. This type accounts for about 45% of multiple myeloma cases and is usually less aggressive.
- Non-hyperdiploid or hypodiploid. These myeloma cells have fewer chromosomes than normal. This more aggressive type affects about 40% of people with the disease.
There are several different kinds of multiple myeloma. There also are several precancerous conditions that can sometimes lead to multiple myeloma.
1. Light Chain Myeloma
Most people with myeloma make antibodies known as immunoglobulins. If you only make an incomplete immunoglobulin known as light chain antibody, you have light chain myeloma. Only 20% of people with myeloma have this kind. These proteins can collect in the kidneys and damage them.
2. Non-secretory Myeloma
Some people with multiple myeloma don't make enough M proteins or light chains for tests to show they have it. This is called non-secretory myeloma. A bone marrow biopsy can help diagnose this type of myeloma.
3. Solitary Plasmacytoma
When plasma cells become cancerous and grow out of control, they can create a tumor called a plasmacytoma, usually in a bone or other tissue. If you have one of these, it's called a solitary plasmacytoma. If you have more than one in different locations, it's multiple myeloma.
Your doctor probably will want to do a combined PET-CT scan or an MRI (magnetic resonance imaging) to confirm the diagnosis. PET stands for positron emission tomography, which uses radiation to make 3-dimensional images, and CT is short for computerized tomography, which takes several X-rays from different angles and puts them together to show more information. An MRI uses powerful magnets and radio waves to make detailed images.
You may have radiation, surgery, or both to treat it.
People with solitary plasmacytoma have a higher risk for multiple myeloma, so you'll need regular checkups.
4. Extramedullary Plasmacytoma
These tumors start outside the bone marrow in the body's soft tissues. Usually, they happen in your throat, sinuses, nose, and larynx (or voice box). Up to 30% of people with extramedullary plasmacytomas will get multiple myeloma. Treatment involves radiation therapy, surgery, or both.
5. Monoclonal Gammopathy of Undetermined Significance (MGUS)
This is a condition that can lead to active myeloma. It involves M proteins, which are abnormal antibodies made by myeloma cells. But MGUS doesn't cause other symptoms of myeloma.
In people who live with this condition for 20 years, only 1 in 5 get active myeloma. People with MGUS usually aren't treated unless they have side effects, such as pain and numbness in their hands, feet, or thighs; muscle weakness; bleeding; or heart or kidney problems.
You may have lab tests every 3 to 6 months to check for an increase in M proteins or signs of the organ damage active myeloma can cause.
6. Smoldering Multiple Myeloma (SMM)
This is a precancerous form of myeloma. Like MGUS, there usually aren't symptoms.
People with smoldering multiple myeloma have more M proteins in their blood or more myeloma plasma cells in their bone marrow. As a result, they're more likely to get active myeloma. About 50% will be diagnosed with myeloma after 5 years.
Your doctor may recommend imaging tests to look at your bones. These may include a skeletal survey, an MRI, or a combined PET-CT scan.
7. Immunoglobulin D (IgD) Myeloma
This rare type affects only 1% to 2% of all people with myeloma. Men under 60 are most likely to get it. The signs and symptoms are the same as other types.
8. Immunoglobulin E (IgE) Myeloma
IgE is the rarest type of multiple myeloma. It causes the same signs and symptoms as other types of multiple myeloma. It tends to be aggressive and progresses to plasma cell leukemia or spreads outside the bone marrow quickly.