Types of myeloma

Last updated Oct. 29, 2025, by Lindsey Shapiro, PhD
Fact-checked by Ana de Barros, PhD

The rare blood cancer myeloma can be classified into a number of different types, each carrying its own characteristics and prognosis. Identifying the myeloma type at diagnosis is key to determine the appropriate treatment plan.

Diagnosis and classification

Myeloma is a cancer that arises from plasma cells — the white blood cells that produce antibodies to help the body fight infection — within the bone marrow, the spongy center of bone where blood cells are made. These plasma cells are genetically abnormal, causing them to grow out of control and produce a dysfunctional antibody called M protein.

Once a myeloma diagnosis is reached, additional tests are run to determine the disease type. When classifying myeloma, a few factors are considered:

whether or not there are symptoms
the type of M protein produced by abnormal plasma cells
the location of the cancerous cells in the body
the specific genetic characteristics of the cancer cells.

Accurate myeloma classification helps doctors decide the right monitoring and treatment plan to ensure the best possible outcomes.

Multiple myeloma

Multiple myeloma is characterized by the widespread presence of myeloma cells throughout the bone marrow, with multiple areas affected at one time. These cells crowd out other healthy blood cells and produce large amounts of identical M proteins, or monoclonal proteins.

Multiple myeloma can be broadly classified as smoldering or active based on whether or not these accumulating plasma cells are causing organ damage and associated symptoms.

Smoldering myeloma

Smoldering multiple myeloma (SMM) is an early precancerous stage where blood and urine tests show evidence of abnormal plasma cells and/or M protein, but there are no clinical signs or symptoms of myeloma.

SMM is technically not cancer, and is not treated unless a person is considered to be at a high risk of progression to symptomatic myeloma. However, many people with SMM — around 50% in the first five years — will go on to develop active disease so the condition requires careful monitoring.

Symptomatic myeloma

Symptomatic, or active, multiple myeloma is characterized by the presence of signs or symptoms of organ damage due to myeloma cells and the abnormal proteins they produce, such as:

bone pain and other issues related to a type of bone tissue destruction called osteolytic lesions
frequent infections due to low white blood cell counts and immune system dysfunction
signs of high blood calcium levels, including confusion, constipation, nausea, vomiting, and urinary changes
kidney failure, including symptoms such as excessive thirst and frequent urination
fatigue and shortness of breath because of too few red blood cells (anemia).

In contrast to SMM, a diagnosis of active multiple myeloma warrants immediate treatment. While this form of cancer cannot be cured, treatment may help control the disease, ease symptoms, prevent further organ damage, and improve life quality.

Other myeloma classifications

Myeloma can also be further classified based on the type of M protein that the myeloma cells are producing and the location of the cancerous plasma cells. These classifications help physicians further determine a person’s prognosis and treatment course.

Myeloma by antibody type

Multiple myeloma exists in various subtypes based on the type of abnormal antibodies, or M protein, that’s produced, and this can influence the course of disease.

Antibodies, or immunoglobulins (Ig), have a Y-shaped structure made up of two long protein fragments (heavy chains) and two shorter fragments (light chains). There are five heavy chain types — IgG, IgA, IgD, IgE, and IgM — and two light chain types, kappa and lambda.

These antibodies can exist in various combinations, but a person’s myeloma cells will produce only one type:

IgG myeloma, particularly IgG-kappa, is the most common form, occurring in more than half of people with multiple myeloma.
IgA is the second most common form, and is linked to a worse prognosis than IgG myeloma, with lower survival rates.
IgD, IgE, and IgM myeloma are rare. IgM myeloma is very rare, with IgM antibodies more commonly associated with a different blood cancer called Waldenström’s macroglobulinemia. IgE myeloma is considered extremely rare.

Light chain myeloma

In about 15% of cases, myeloma cells produce only the light chain part of the antibody. This is known as light chain myeloma, or Bence Jones myeloma, and can exist in kappa or lambda subtypes.

Light chain myeloma is an aggressive form of the disease and has been associated with worse survival than IgA or IgG myeloma, as well as higher rates of kidney failure and bone disease. Some research suggests the lambda subtype has a worse prognosis than the kappa type.

These light chains can also form deposits in the kidneys, nerves, or other tissues, leading to a related condition known as amyloidosis, which can cause organ damage.

Non-secretory myeloma

Quite rarely, in up to 3% of cases, myeloma cells produce very little to no M proteins of any type.

This myeloma subtype can be difficult to track, since M protein levels in the blood and urine are usually central to myeloma diagnosis and monitoring.

Although myeloma cells are not producing M proteins, this form of the disease can still lead to the same types of organ damage as other forms of active myeloma.

Myeloma by location

Multiple myeloma is typically found in multiple locations throughout the bone marrow. In rare cases, the cancer can spread to the bloodstream or other tissues, leading to more aggressive and difficult-to-treat forms of the blood cancer.

Extramedullary myeloma

Sometimes, myeloma cells form tumors, or plasmacytomas, in the soft tissues outside of the bones.

This is an aggressive form of multiple myeloma known as extramedullary disease. It can be present at the time of diagnosis but may also arise later, when the cancer spreads because it did not respond to treatment.

Extramedullary myeloma is generally associated with a poorer prognosis than myeloma that’s restricted to the bone marrow in both newly diagnosed and relapsed/refractory patients.

Plasma cell leukemia

Plasma cell leukemia (PCL) is a rare and aggressive type of multiple myeloma wherein abnormal myeloma cells are found circulating in the bloodstream.

In some cases, the cancer is found already circulating in the bloodstream at the time of diagnosis (primary PCL), and in others, it spreads to the bloodstream after multiple myeloma of the bone marrow has already been diagnosed and spread (secondary PCL).

The symptoms of PCL are similar to those of typical multiple myeloma, but may be more severe. The treatment is also similar. PCL is very aggressive and has a poorer prognosis than typical multiple myeloma.

Comparison of myeloma types

While each of these myeloma types originate from abnormal plasma cells, they have distinct characteristics that influence their prognosis.

In general, smoldering myeloma is the mildest form of the disease, without any symptoms or evidence of cancer-related damage in the body. Among the subtypes of active multiple myeloma, those associated with a more aggressive disease course include:

myeloma associated with IgA and light chain antibody types
myeloma that has spread out of the bone marrow, including extramedullary disease and plasma cell leukemia.

The symptoms of different myeloma types are generally similar, but may vary in severity. All forms of active myeloma require treatment, but different approaches may be used depending on the aggressiveness of the cancer.

Conditions related to myeloma

Myeloma is also related to other conditions that involve abnormal plasma cells or other immune cells, but are distinct diseases. In some cases, such conditions can become multiple myeloma later on.

Monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a precancerous condition wherein a low number of myeloma cells and M protein can be detected, but in small amounts.

Essentially all people with myeloma first have MGUS, but not all people with MGUS develop myeloma. About 1% of people with MGUS develop myeloma or another serious blood disorder each year.

Like smoldering myeloma, MGUS does not have symptoms and is not treated, but requires careful monitoring to identify signs of myeloma progression as promptly as possible.

Solitary plasmacytoma

While multiple myeloma is characterized by plasma cell cancer in multiple areas of the bone marrow, solitary plasmacytoma is a related plasma cell cancer where myeloma cells form a solitary tumor in a single location. It exists in two forms:

Plasmacytoma of the bone, where the tumor forms in the bone or bone marrow. The main symptom is bone pain, without other signs of myeloma-related organ damage.
Extramedullary plasmacytoma, where the tumor is found in soft tissues outside the bone marrow. It most commonly occurs in the upper respiratory tract, but can grow anywhere. Symptoms depend on the tumor location.

This condition is often treated with radiation therapy. The prognosis is generally good if it does not progress to multiple myeloma.

Solitary plasmacytoma may sometimes be thought of as an intermediate phase between MGUS and active multiple myeloma. Up to around 70% of people with solitary plasmacytoma, particularly if it affects the bone, go on to develop multiple myeloma.

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