What are the different types of plasma cell disorders?
We actually have a lot of different ways that we use to classify plasma cell problems. So probably the most important is to differentiate between disorders that are symptomatic and asymptomatic. And the terms that we use for asymptomatic disorders include monoclonal gammopathy of undetermined significance, abbreviated MGUS, and smoldering multiple myeloma, which is often abbreviated SMM. And the most important characteristic of MGUS and smoldering myeloma is that they are not causing problems. And so while there are distinctions that we use in the amount of plasma cells in the bone marrow, the level of the abnormal monoclonal protein in the blood, that differentiate between them, it's not necessarily very important that differentiate between them, it's not necessarily very important to be able to tell the difference between MGUS and smoldering myeloma. The differences have largely to do with what the risk is that over time, they'll become more symptomatic. but the key characteristic is that because they're generally not causing symptoms, we usually don't do any treatment for the asymptomatic disorders. And that's very different from multiple myeloma or sometimes called active or symptomatic multiple myeloma, where the myeloma is causing problems. And the typical problems that we see from myeloma are lytic bone lesions, high calcium levels, low blood counts, especially anemia, as a predisposition to infection from, decrease in the immune system. active or symptomatic myeloma generally needs to be treated with chemotherapy treatments, and in order to prevent it from causing more problems. In addition to those larger classifications of patients with myeloma, there are a couple of important subsets of patients with plasma cell disorders that don't quite fit into the diagnosis of multiple myeloma. Some patients will present with only one lump of plasma cells someplace in their body. A lump of plasma cells is called a plasmasytoma. And if a patient has a plasmasytoma and only one and there are no abnormal plasma cells in the bone marrow and no other areas of the body that are affected by multiple myeloma, then we call that plasmacytoma a solitary plasmacytoma. And a solitary plasmcytoma is really important to identify because some percentage of solitary plasmacytomas can be cured with local radiation alone and don't require any chemotherapy. That's a very different situation from a patient who has several plasmacytoma or who has a plasmasytoma. But evidence of myeloma affecting the body or the bones in other places than single plasmacytoma because in that case, if there's evidence of myeloma outside that one area, we would not call it a solitary plasmacytoma and we generally would not try to cure it with radiation. Plasma cell leukemia is a term that refers to a particularly aggressive form of multiple myeloma, where the myeloma cells instead of staying in the bone marrow, where they usually live, develop the ability to leave the bone marrow and come out into the blood. And if there are a lot of plasma cells in the blood, then we call it plasma cell leukemia. Although the overall treatment remains the same as for multiple myeloma, meaning we give medicines to kill the plasma cells and try to bring them under control and stop them from causing problems. And in general, plasma cell leukemia is more difficult to control, tends to have poor response to therapy, and tends to grow more aggressively. In addition to all of those disorders, there are a few plasma cell diseases that present in very different ways from multiple myeloma, usually because the plasma cells have the ability to cause some other problem. And so in this category, we would put diseases like primary And so in this category, we would put diseases like primary or AL amyloidosis, where the light chains produced by the plasma cells have the ability to get along together in sheets of protein and deposit in organ tissues. We would also include kidney diseases like light chain deposition disease or membranoproliferative glomerulonephritis with monoclonal immunoglobulin deposition and disorders like POEMS syndrome where for all of these the underlying problem remains the abnormal plasma cells in the bone marrow. And the overall treatment is similar to myeloma in that we try to use medicines to kill those plasma cells and stop them from causing all of the other problems.
