Myeloma is also known as multiple myeloma or myelomatosis.

Blood cells look and work differently, but they all repair and reproduce themselves in the same way. Normally, new cells are produced to replace old, worn-out cells in an orderly, controlled way. However, in myeloma the process gets out of control and large numbers of abnormal plasma cells – myeloma cells – are produced. These fill up the bone marrow and interfere with production of normal white cells, red cells and platelets.

The myeloma cells usually produce a large amount of one type of abnormal antibody. This is known as a paraprotein or M protein. This paraprotein cannot fight infection effectively and often reduces the production of normal antibodies.

Myeloma cells have the ability to spread throughout the bone marrow and into the hard outer casing of the bone. Some, or many, areas of bone may be affected. Myeloma can cause thinning of the outer bone and bone pain.

Myeloma usually occurs in middle-aged and older people. It is unusual before the age of 50 and very rare in people younger than 40.

Myeloma is one type of disorder of the plasma cells. Some other conditions of the plasma cells can develop into myeloma but may not necessarily do so. The two most common of these are monoclonal gammopathy of uncertain significance (MGUS) and smouldering myeloma (also known as indolent or asymptomatic myeloma). If you are diagnosed with either of these conditions, you will be monitored with blood tests, but may not need to have any treatment unless the condition progresses.

Sometimes abnormal plasma cells are found in a bone in only one area of the body. This condition is known as a solitary plasmacytoma. It is treated with radiotherapy. Some people with solitary plasmacytoma may go on to develop multiple myeloma, so you will be regularly monitored with blood tests.