Updated on November 21, 2021mMedically reviewed by Todd Gersten, M.D.Article written by Kelly Crumrin
Multiple myeloma is a blood cancer that occurs when one type of
white blood cell called a lymphocyte develops abnormalities and grows out of
control. Multiple myeloma and its related disorders affect a type of lymphocyte called plasma
cells, also known as plasma B cells. Some plasma cell disorders are cancerous
conditions, while others are not. In myeloma, abnormal versions of plasma cells
are overproduced. They crowd out healthy cells and form tumors. Most tumors
form in the bone marrow, causing pain, weakening the bones, and limiting the
production of healthy blood cells. In some people, tumors form in soft tissues
such as the throat, sinuses, lungs, or muscles.
Normal plasma cells secrete proteins called
immunoglobulins — also known as Ig or antibodies — that recognize and destroy
specific viruses and other threats. Antibodies produced by healthy plasma cells
are an important part of the immune system. In plasma cell disorders, abnormal
plasma cells secrete ineffective antibodies that do not provide protection,
weakening the immune system and leaving the body unprotected from infection. In
some cases, so many abnormal antibodies are present in the bloodstream that
they interfere with blood flow and damage the kidneys.
Some types and stages of plasma cell disorders are mild and
asymptomatic. They do not cause any symptoms, do not require treatment, and may never progress to cancer.
Other types and stages can be life-threatening and must be treated urgently.
Once someone has been diagnosed with a plasma cell disorder, they must be
monitored regularly for progression.
Read more about how myeloma is diagnosed.
Types of Plasma Cell Disorders
Researchers believe that mild, asymptomatic types of plasma cell
disorders always precede a
cancer like multiple myeloma, although they are not caught and diagnosed in
every person. However, the precancerous conditions only progress to cancer in a
small fraction of people. Many people never progress from a milder disorder to
multiple myeloma. Being diagnosed with a mild plasma cell disorder does not
mean you will definitely develop multiple myeloma. Having a mild disorder means
that, if your condition does progress, regular screenings will ensure that you
receive a new diagnosis and treatment as early as possible.
Monoclonal Gammopathy of Undetermined
Significance
Monoclonal gammopathy of undetermined significance (MGUS) is
diagnosed when abnormal antibodies —
called monoclonal proteins or M proteins — are found in the blood, usually
during blood tests for unrelated conditions. MGUS is not a cancerous condition
and does not involve a tumor. People with MGUS have a 1 percent chance
each year of their condition progressing to multiple myeloma. People may also
progress to other more serious plasma cell disorders, like smoldering multiple
myeloma, or to conditions related to abnormal antibodies, like amyloidosis or
light chain deposition disease. MGUS is asymptomatic.
The standard recommendation is for watchful waiting instead of treatment for
MGUS. People diagnosed with MGUS may undergo blood and urine testing once every six or 12 months to
monitor for progression. Doctors classify MGUS as having a low, intermediate,
or high risk of progressing to myeloma. However, risk levels can get worse over
time. Doctors now recommend that
everyone with MGUS, including those with few risk factors, get screened
regularly for myeloma.
If routine monitoring shows evidence of progression, your
doctor may recommend beginning
treatment. Those diagnosed with both MGUS and osteoporosis may take a
bisphosphonate medication, such as Aredia
(pamidronate) or Zometa
(zoledronic acid), to help maintain bone mineral density.
Subtypes of MGUS
include IgM MGUS, non-IgM MGUS, and light chain MGUS.
Read more about MGUS.
Smoldering Multiple Myeloma
Like MGUS, smoldering multiple myeloma (SMM) is
a disorder involving abnormal antibodies in the blood with no myeloma signs or
symptoms. Some doctors are now calling this condition asymptomatic myeloma. In
some people, SMM progresses to multiple myeloma. People with SMM have a
higher risk for disease progression than those
with MGUS, although this risk decreases over time:
·
For the first five
years after being diagnosed with SMM, a person has a 10 percent risk of
developing myeloma each year.
·
For the next five
years, a person has a 3 percent chance per year of developing myeloma.
·
Ten years or more
after SMM diagnosis, a person has a 1 percent chance of developing myeloma each
year.
Rarely, when the abnormal plasma cells of someone with SMM are
tested, they show specific genetic characteristics that carry a risk of
progression much higher than the average.
Some people have a higher burden of abnormal cells than others, as measured by
blood tests and bone marrow biopsy. In this subset of high-risk SMM cases,
doctors may recommend beginning treatment to
delay the progression to cancer. Ongoing clinical trials are helping doctors
learn more about which treatments can best improve outcomes for people with
SMM.
Researchers believe either MGUS or SMM precede all cases of multiple myeloma.
Read more about smoldering multiple myeloma.
Solitary Plasmacytoma
If one cancerous tumor formed by abnormal plasma cells is
present, it is known as a solitary plasmacytoma.
Solitary plasmacytomas most frequently develop in bone, where they are known as
solitary bone plasmacytomas or solitary medullary plasmacytomas. Symptoms of
solitary bone plasmacytoma depend on where the tumor is located, but it may cause pain, fracture,
or compression of the spinal cord. Some cases of solitary bone plasmacytoma are
cured with radiation therapy. Between 50 percent and 70 percent of
people diagnosed with solitary bone plasmacytoma progress to multiple myeloma
within a few years.
Extramedullary Plasmacytoma
A plasmacytoma may also grow in soft tissues such
as the nose, throat, lung, bladder, or muscle. A plasmacytoma that occurs in
soft tissue is called an extramedullary plasmacytoma. About 80 percent of solitary extramedullary
plasmacytomas occur in the upper respiratory tract — in the nose, sinuses, or
upper throat.
Signs and symptoms of extramedullary plasmacytoma depend on the
location, but may include pain or
obstruction — for instance, an obstruction of the respiratory, urinary, or
digestive tract. A solitary extramedullary plasmacytoma has a lower risk of
progressing to multiple myeloma — approximately 8 percent.
Extramedullary plasmacytomas may also occur in addition to bone tumors in those
with multiple myeloma.
Localized Myeloma
In cases of a plasmacytoma that is spreading to just a few
neighboring sites, the term localized myeloma may
be used. Localized myeloma differs from multiple myeloma because the cancer is
still confined to one area of the body rather than widespread.
Multiple Myeloma
Multiple myeloma is diagnosed when cancerous plasma cells cause widespread problems throughout the
body. Bones are the most common site for cancer cells to build up, but tumors
in soft tissue (extramedullary plasmacytomas) can also develop. Signs and symptoms of multiple myeloma
can be severe and may include:
·
Bone pain, weakness,
or breaks
·
Spinal cord
compression (weakened bones in the spine pressing on nerves), which causes back
pain and leg numbness or weakness
·
Anemia (low red blood
cell levels), which causes fatigue and weakness
·
Leukopenia (low
numbers of white blood cells), which leads to frequent infections
·
Thrombocytopenia (low
platelet counts), which causes bleeding problems
·
Hypercalcemia (high
calcium levels), which causes dehydration, extreme thirst, frequent urination,
constipation, abdominal pain, tiredness, and confusion
·
Kidney damage or
failure, which leads to shortness of breath, itching, and swelling of the legs
Myeloma cells produce large amounts of abnormal antibodies.
Doctors sometimes classify cases of multiple myeloma into subtypes based on which types of
antibodies are being made. Myeloma may be classified as IgG, IgA, IgD, IgE, or
IgM. Rarely, myeloma cells don’t make any (or very few) antibodies. Doctors
call this non-secretory myeloma.
Multiple myeloma is a dangerous plasma cell disorder. Multiple
myeloma currently is not curable in most cases, and it can be
fatal. However, it is highly treatable. New multiple myeloma treatment options
can keep the condition under control for a long time.
When multiple myeloma is diagnosed, doctors assign it a stage.
The stage of myeloma reflects how far the myeloma has progressed. Read more
about stages of multiple myeloma.
Relapsed Myeloma
Multiple myeloma that has returned after a previous effective
treatment is known as relapsed myeloma.
Relapsed myeloma may be treated with the same treatments that were effective
before, or doctors may recommend different treatments after
a relapse.
Refractory Myeloma
Multiple myeloma that has progressed despite treatment is
called refractory myeloma.
Refractory myeloma is by definition more difficult to treat. Some people with
refractory myeloma participate in a clinical trial for a chance to access
experimental cancer treatments.
Light Chain Myeloma
In most cases of multiple myeloma, cancerous plasma cells
secrete abnormal antibodies. In about 15 percent of cases, myeloma cells
secrete only fragments of antibodies known as light chain proteins or
Bence-Jones proteins. This is known as light chain myeloma. Light chain myeloma
can be further subtyped by the type of light chain protein as either kappa
light chain myeloma or lambda light chain myeloma. People with light chain
myeloma are significantly more likely to experience kidney failure than those
with non-light chain myeloma.
Read more about light chain myeloma.
AL Amyloidosis
AL amyloidosis is another condition that affects light chain
proteins. AL amyloidosis is not cancer, and people with this condition don’t
have high levels of plasma cells. In AL amyloidosis, plasma cells make high levels of abnormal light chain
protein. The proteins stick together, forming clumps called amyloid deposits.
The deposits build up in tissues throughout the body and cause organ damage.
People with AL amyloidosis may have decreased kidney function, heart damage,
digestive system problems, and neuropathy. AL amyloidosis is treated with many
of the same treatments that are used for multiple myeloma.
Condition Guide
·
Multiple Myeloma — An Overview
·
Symptoms of Multiple Myeloma
·
Multiple Myeloma — The Path to Diagnosis
·
What Causes Multiple Myeloma?
https://www.mymyelomateam.com/resources/myeloma-types-and-related-conditions
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