Plasma cell myeloma, or multiple myeloma, is a cancer of the plasma cells where the cells form tumors within bone marrow, potentially preventing its main function of creating blood cells, according to the National Cancer Institute. These tumors also weaken and damage the bones that contain the marrow.
Myeloma cells are a particular type of plasma cell, which are themselves a type of white blood cell, part of the immune system of the body, the National Cancer Institute explains. The bone marrow creates white blood cells, the red blood cells that carry oxygen and platelets that allow blood to clot. Multiple myeloma does not necessarily cause any symptoms and is often detected when tests for other conditions are performed. When symptoms are present, they can include brittle bones, bone pain, a lowered immune system, fatigue, weakness, easy bruising and easy bleeding. These symptoms can all be caused by other conditions, making initial detection difficult.
Complications of multiple myeloma include hypercalcemia and amyloidosis, according to the National Cancer Institute. Hypercalcemia is an overabundance of calcium in the blood, caused by the damage myeloma tumors do to bone. It can cause severe health problems and affect the heart, kidneys and other organs. Amyloidosis is the formation of clumps of antibody proteins on nerves and organs that interfere with their function.