Types of myeloma

• A quick guide to what's on this page
• Types of immunoglobulin
• Light chain myeloma
• Non secretory myeloma
• Other conditions related to myeloma

There is really only one main type of myeloma, but in different people, the cancerous plasma cells make different antibodies. Doctors more often call these antibodies ‘immunoglobulins’. In each case of myeloma, only one type of immunoglobulin is overproduced, but this varies from patient to patient. There are 5 basic immunoglobulins - A, G, M, D and E. In myeloma, IgG is the most common, and IgE is the rarest. So, for example, you may be told you have IgG myeloma.

But some people with myeloma do not produce complete immunoglobulins. They only produce part of the immunoglobulin called the 'light chain' or Bence Jones protein. About one in 5 people with myeloma (20%) produce only light chains. Doctors call this light chain myeloma or Bence Jones myeloma. The light chains are smaller and show up in the urine, not the blood. So you need urine tests to diagnose and monitor your myeloma.

In less than 2 out of 100 (2%) people with myeloma the immunoglobulin (paraprotein) does not show up in the blood or the urine. Doctors call this non secretory myeloma. As you can imagine it is harder to diagnose this type of myeloma. But a new blood test for myeloma called 'serum free light chain test' can help detect small amounts of free light chains in the blood. This is useful for diagnosing and monitoring this type of myeloma.

There are other conditions of the plasma cells that are related to myeloma

• MGUS
• Plasmacytoma
• Amyloidosis

MGUS

There is another condition called monoclonal gammopathy of undetermined significance or ‘MGUS’ for short. Your plasma cells are making too much of the large protein molecules known as immunoglobulins. This shows up in the blood. MGUS is often found by chance, through blood tests carried out as part of a routine check up, or tests for some other medical problem. This is because this condition does not cause any symptoms, and does not generally affect your health.

MGUS is diagnosed if you have

• a low level of abnormal paraprotein in your blood (less than 30 g/l)
• a low level of abnormal plasma cells in your bone marrow (less than 10%)
• no evidence of certain other related conditions
• no related organ or tissue impairment

Because it does not seem to do you any harm, MGUS does not need treating. But if you have MGUS, you will be asked to see a specialist regularly for a check up. This is because 2 or 3 people out of every 10 (20 - 30%) diagnosed with MGUS will go on to develop myeloma. But this may not happen for many years. The risk appears to be linked to the level of abnormal protein you have. A low level of protein means your risk of developing myeloma is lower.

Plasmacytoma

Sometimes, myeloma is found in just one place in the body. This is called a solitary plasmacytoma. Sometimes, people with solitary plasmacytoma will go on to develop myeloma later in life. Some doctors call this stage 1 myeloma.

Either single or multiple plasmacytomas can grow outside the bone marrow, for example in the head and neck area. Plasmacytoma that develops outside the bone marrow is called soft tissue plasmacytoma. It usually responds well to radiotherapy treatment.

Amyloidosis

This is really a collection of conditions. An abnormal protein called amyloid is made by the plasma cells. The amyloid collects in the body organs, such as the kidney or heart. About 10 to 15 out of every 100 (10-15%) people with myeloma will either have, or develop, amyloidosis. It is rare for people with amyloidosis to develop myeloma. Doctors usually treat amyloidosis with chemotherapy, and use the same drugs that are used for myeloma.