Other plasma cell disorders exist that contain similar characteristics to multiple myeloma and amyloidosis, but don’t meet the same criteria to be classified as them.
Monoclonal gammopathy of undetermined significance (MGUS)
In MGUS, abnormal plasma cells also make copies of the same abnormal antibody, but these cells do not cause the same problems seen in multiple myeloma. While there is still an increase in plasma cells, the cells still only account for less than 10% of the cells in the bone marrow. MGUS is not classified as a cancer, but can be pre-malignant, meaning an individual with MGUS may eventually develop multiple myeloma, lymphoma, or amyloidosis.
MGUS often presents with no symptoms and can be found during a routine blood test where a spike in M protein is observed. Although a patient may remain symptom free for some time, it’s important to continue regular checkups to monitor the M protein levels in the blood. In the event that the disease does progress to myeloma, regular checkups can mean starting treatment earlier and catching the disease at an earlier stage.
Developing symptoms such as bone pain, fatigue, weakness, weight loss, fever, night sweats, headache, dizziness, nerve pain, bleeding, anemia, or swollen lymph nodes may indicate disease progression.
Smoldering multiple myeloma (SMM)
Smoldering multiple myeloma is an early version of myeloma that does not cause an individual any problems or symptoms. Smoldering multiple myeloma contains some of the same signs as multiple myeloma, such as an increased amount of plasma cells in the bone marrow, however, blood counts remain normal and there is no sign of amyloidosis or damage to the bones or organs. SMM can take months to years to become active myeloma and some people never develop active disease.
Solitary plasmacytomas is a disorder classified by a plasmacytoma, or an abnormal plasma cell growth that is cancerous. Unlike multiple myeloma, solitary plasmacytoma only presents with one tumor, rather than multiple tumors in different locations. This disorder often develops in a bone, but can also start in other tissue areas, such as the lungs or other organs. Solitary plasmacytomas also has the ability to turn into multiple myeloma down the road.
Waldenstrom macroglobulinemia (WM)
Waldenstrom macroglobulinemia is a disorder that features a combination of cancer cells similar to multiple myeloma and non-Hodgkin lymphoma. WM cells make high amounts of an antibody known as a macroglobulin, but because each antibody is the same, they are considered M-proteins. The buildup of these antibodies leads to excess bleeding, vision problems, and nervous system problems. While WM is grouped with other plasma cell disorders due to the M-protein buildup, it is also grouped with non-Hodgkin lymphoma due to macroglobulin production.