Waldenstrom macroglobulinemia: A chronic low-grade (indolent) type of lymphoma due to a malignant clone of plasma cells. These plasma cells multiply out of control, invade the bone marrow, lymph nodes, and spleen, and characteristically produce huge amounts of a large-sized antibody called macroglobulin or IgM. The excess IgM causes the blood to be hyperviscous (to thicken).
Signs and symptoms of the disease may include enlarged lymph nodes or spleen (splenomegaly), fatigue, headaches, weight loss, a tendency to bleed easily, visual problems, confusion, dizziness, and loss of coordination. The symptoms are largely due to the thickening of the blood. In extreme cases, the increased concentration of IgM in the blood can lead to heart failure.
The treatment depends upon the viscosity of the patient's blood. Patients with pronounced hyperviscosity usually receive chemotherapy (anticancer drugs). A type of treatment called plasmapheresis may be performed to relieve symptoms such as excessive bleeding and dizziness. In this procedure, the blood plasma (which contains the antibody IgM) is removed from the patient. Other parts of the blood (red blood cells, white blood cells, and platelets) are returned to the patient along with a plasma substitute. Interferon alpha, a form of biological therapy, may also help relieve symptoms.