Multiple myeloma and other plasma cell neoplasms (cancers) are diseases in which the body makes too many plasma cells.

Plasma cells develop from B lymphocytes (B cells), a type of white blood cell that is made in the bone marrow. Normally, when bacteria or viruses enter the body, some of the B cells will change into plasma cells. The plasma cells make a different antibody to fight each type of bacteria or virus that enters the body, to stop infection and

Plasma cell neoplasms are diseases in which there are too many plasma cells, or myeloma cells, that are unable to do their usual work in the bone marrow. When this happens there is less room for healthy red blood cells, white blood cells, and platelets. This condition may cause anemia or easy bleeding, or make it easier to get an infection. The abnormal plasma cells often form tumors in bones or soft tissues of the body. The plasma cells also make an antibody protein, called M protein, that is not needed by the body and does not help fight infection. These antibody proteins build up in the bone marrow and can cause the blood to thicken or can damage the kidneys.

In multiple myeloma, abnormal plasma cells (myeloma cells) build up in the bone marrow, forming tumors in many bones of the body. These tumors may prevent the bone marrow from making enough healthy blood cells. Normally, the bone marrow produces stem cells (immature cells) that develop into three types of mature blood cells:

• Red blood cells that carry oxygen and other materials to all tissues of the body
• White blood cells that fight infection and disease
• Platelets that help prevent bleeding by causing blood clots to form

As the number of myeloma cells increases, fewer red blood cells, white blood cells, and platelets are made. The myeloma cells also damage and weaken the hard parts of the bones. Sometimes multiple myeloma does not cause any symptoms. The following symptoms may be caused by multiple myeloma or other conditions. A doctor should be consulted if any of the following problems occur:

• Bone pain, often in the back or ribs
• Bones that break easily
• Fever for no known reason or frequent infections
• Easy bruising or bleeding
• Trouble breathing
• Weakness of the arms or legs
• Feeling very tired

A tumor can damage the bone and cause hypercalcemia (a condition in which there is too much calcium in the blood). This can affect many organs in the body, including the kidneys, nerves, heart, muscles, and digestive tract, and cause serious health problems. For more information on mulitple myeloma and other plasma cell neoplasms, visit the University of Minnesota Masonic Cancer Center site.