Several organs in multiple myeloma patients become enlarged, especially the liver and the spleen. Both organs are essential to clear the blood from toxins, defective cells, and other abnormalities. But even if they try to even out the excess of plasma cells, they cannot bring back their numbers to normal. Another organ that is usually enlarged is the heart, which is known as cardiomegaly. This is because there’s a deposition of immunoglobulin in the heart tissue, which triggers an increase in the organ’s size.