Lymphoplasmacytic lymphoma (LPL) is a slow-growing type of blood cancer made up of abnormal immune cells, including lymphocytes and plasma cells. These cells usually build up in the bone marrow and sometimes in the lymph nodes, spleen, or other tissues, reducing the body’s ability to produce healthy blood cells. Most lymphoplasmacytic lymphomas make a type of antibody (immune protein) called IgM. When the disease involves the bone marrow and produces IgM, it is also called Waldenström macroglobulinemia.
This article will help you understand the findings in your pathology report for lymphoplasmacytic lymphoma, what each term means, and why it matters for your care.
The exact cause of lymphoplasmacytic lymphoma (LPL) is not known, but several factors are linked to a higher risk:
The symptoms of lymphoplasmacytic lymphoma (LPL) are caused by both the buildup of cancer cells and the IgM protein that the cells release into the blood. Common symptoms include:
The diagnosis of lymphoplasmacytic lymphoma (LPL) is usually made by examining a sample of the bone marrow, and sometimes a lymph node or other affected tissue, under the microscope. A pathologist looks for the characteristic mixture of small lymphocytes, plasma cells, and intermediate cells (described in the next section).
Specialized tests confirm the diagnosis. Immunohistochemistry and flow cytometry use antibodies to detect proteins on and inside the cells. In lymphoplasmacytic lymphoma, the cells carry B-cell markers such as CD19, CD20, CD22, CD79a, and PAX5, usually show IgM, and are typically negative for CD5, CD10, CD23, and CD103. This pattern helps separate lymphoplasmacytic lymphoma from other slow-growing B-cell cancers such as chronic lymphocytic leukemia. A blood test called serum protein electrophoresis measures the IgM protein and shows it as a sharp peak (an “M-spike”). Testing for the MYD88 mutation, described below, also supports the diagnosis.
Under the microscope, lymphoplasmacytic lymphoma (LPL) in the bone marrow consists of an abnormal mixture of small lymphocytes, plasmacytoid lymphocytes (cells that are partway between lymphocytes and plasma cells), and plasma cells. Some additional features are common:
When the disease involves a lymph node or the spleen, a similar mixture of small lymphocytes, plasmacytoid lymphocytes, and plasma cells is seen, sometimes partially replacing the normal tissue architecture.
Molecular tests look for specific genetic changes inside the cancer cells of lymphoplasmacytic lymphoma (LPL). Two are especially important because they help confirm the diagnosis and guide treatment:
Your report will state whether these mutations were found.
Waldenström macroglobulinemia is a type of lymphoplasmacytic lymphoma (LPL) characterized by the buildup of cancer cells in the bone marrow and elevated levels of IgM in the blood. Because most lymphoplasmacytic lymphomas make IgM and involve the bone marrow, the two terms are often used to describe the same disease. A small number of lymphoplasmacytic lymphomas make a different protein (such as IgG or IgA) or make no protein at all, and these are not called Waldenström macroglobulinemia.
Both lymphoplasmacytic lymphoma (LPL) and multiple myeloma involve abnormal plasma cells, but they behave differently. Multiple myeloma usually causes bone damage, high calcium levels, and kidney injury, and it most often makes IgG or IgA protein. Lymphoplasmacytic lymphoma usually does not cause these problems; it more often produces IgM and is composed of a mixture of lymphocytes and plasma cells rather than plasma cells alone.
Lymphoplasmacytic lymphoma (LPL) is a slow-growing cancer, and many patients live for many years after diagnosis, often more than a decade. The prognosis depends on a combination of factors rather than any single result:
Your prognosis depends on your own combination of these factors, which your care team can explain in the context of your specific report.
Once lymphoplasmacytic lymphoma (LPL) is confirmed, treatment is based on whether the disease is causing symptoms, the IgM level, and the genetic findings. The pathology findings help guide several decisions:
Care is usually provided by a hematologist or oncologist, along with other specialists, and the MYD88 and CXCR4 results help the team decide which treatment is most likely to be effective. Decisions about whether and when to treat are made by the care team together with the patient, based on the specific findings in the report. Clinical trials may also be an option to discuss.