About 10 to 15 percent of people with multiple myeloma, also called myeloma, develop a condition called amyloid light-chain (AL) amyloidosis, according to 2021 research.

Multiple myeloma is a cancer that forms in a type of white blood cell called a plasma cell. Plasma cells produce proteins called antibodies that protect your body from foreign invaders like viruses and bacteria.

AL amyloidosis occurs when pieces of antibodies produced by plasma cells called light chains break off and build up in your organs. The development of AL amyloidosis is associated with a poorer outlook in people with myeloma, especially when light chains build up in the heart.

Keep reading to learn more about AL amyloidosis in people with myeloma, including symptoms, diagnosis, and treatment.

Multiple myeloma and AL amyloidosis are two closely related conditions that are frequently diagnosed together.

Multiple myeloma and plasma cells

Multiple myeloma is a blood cancer that develops in plasma cells found in your bone marrow.

Healthy plasma cells create Y-shaped proteins called antibodies that help your body kill germs. These proteins bind to areas on the surface of germs like a lock and key. This binding tags the invader so that other immune cells know to attack it.

In people with multiple myeloma, cancerous plasma cells make atypical antibodies called monoclonal proteins (M-proteins). M-proteins can crowd out healthy blood cells and cause symptoms like fatigue and frequent infection.

AL amyloidosis and light chains

Antibodies are made up of two molecules called heavy chains and two molecules called light chains. AL amyloidosis develops when cancerous plasma cells secrete misshapen and overabundant light chains. These light chains build up in your organs and become deposits called amyloid.

Amyloid can cause organ dysfunction, enlargement, and failure. It can develop in multiple organs or just one. According to a 2019 study, the most common places for it to develop are:

OrganPercent of cases
soft tissue15%
peripheral or autonomic nervous system10%
gastrointestinal tract5%

Multiple myeloma and AL amyloidosis are frequently diagnosed together.

The main problem in multiple myeloma is that abnormal plasma cells develop in the bone marrow and proliferate, crowding out healthy blood cells. These abnormal cells produce antibodies called M-proteins that can cause kidney damage and other issues.

The main problem in AL amyloidosis is that amyloid builds up in organs.

Symptoms of multiple myeloma are typically referred to with the acronym CRAB, which stands for:

  • C: elevated calcium
  • R: renal (kidney) failure
  • A: anemia, or a low blood cell count
  • B: bone damage

Symptoms of AL amyloidosis are broad, depending on which organs are affected. Many of the symptoms of AL amyloidosis and multiple myeloma overlap.

In a 2018 study, symptoms were reported in the following frequencies by 341 people with AL amyloidosis:

AL amyloidosisEarly diagnosis (<6 months)Delayed diagnosis (≥6 months)
shortness of breath52.7%71.8%
swelling in ankles or legs61.1%67.9%
dizziness when standing41.1%57.9%
loss of appetite38.7%56.7%
alternating constipation and diarrhea27.8%32.6%
unintentional weight loss35.1%41.3%
enlarged tongue13.8%23.1%
numbness of arms and legs20.0%47.9%
purple color around eyes18.3%27.3%

According to a 2022 review, amyloidosis develops in people with multiple myeloma as the cancerous myeloma cells make large quantities of abnormal light chains.

In some people, the molecular characteristics of these light chains cause them to clump together and form structures called fibrils, which deposit in the tissues. The deposited fibrils destroy the usual form and function of an organ.

Affected organs can include the:

  • heart
  • liver
  • kidneys
  • nervous system
  • gastrointestinal tract

A 2021 study suggests about 10 to 15 percent of people with multiple myeloma develop AL amyloidosis and about 10 percent of people with AL amyloidosis have symptomatic multiple myeloma when they’re diagnosed.

AL amyloidosis and multiple myeloma share some genetic risk factors. The primary risk factor for AL amyloidosis is age. According to 2018 research, the median age of diagnosis is 64.

Diagnosis and treatment of AL amyloidosis is often delayed, according to a 2021 case report, because it causes nonspecific symptoms.

A 2021 review suggests the median time from the beginning of symptoms to diagnosis is 6 to 12 months, with the average person visiting 3 to 4 doctors before their diagnosis is confirmed. Diagnosis is usually most straightforward in people with kidney symptoms.

For an AL amyloidosis diagnosis, doctors need to take a tissue sample to find evidence of amyloid buildup in your organs.

If AL amyloidosis is suspected, your doctor will first take a small sample with a needle from an easily accessible tissue, like the fat under your skin. This procedure is called a fat aspiration. Fat aspiration combined with a bone marrow biopsy can diagnose AL amyloidosis in about 90 percent of people.

Special staining will be applied to your tissue sample in a lab to look for signs of amyloid. The most commonly used stain is called Congo red. Additional lab tests will be done to analyze what type of protein is building up.

A 2021 review found that the three pillars for improving the survival of AL amyloidosis include:

  • early detection
  • anti-plasma cell therapy
  • supportive care

The primary treatment for multiple myeloma with AL amyloidosis is targeting the underlying cancerous plasma cells.

This might include:

Targeting amyloid deposits using monoclonal antibodies is under investigation, but it has not been approved yet.

A 2021 study on 1,357 people with AL amyloidosis showed a median survival of 4 years. However, people who received their diagnoses at late stages of the disease had much shorter overall survival. According to 2020 research, how much your heart is affected is another of the most important factors determining your outlook.

In multiple myeloma without amyloidosis, the National Cancer Institute says outcomes have improved dramatically over the last 2 decades.

Other experts looked at long-term follow-up of one of the most common regimens for treatment of multiple myeloma in a 2021 study. Their research demonstrated a median overall survival of 126 months in all people and 78 months in people at high risk.

But a number of different factors play into these estimates. For example, the stage of cancer at diagnosis and the organs affected by AL amyloidosis can change your situation. It’s always best to talk with your doctor to determine your individual outlook.

Multiple myeloma is a cancer that develops in plasma cells in your bone marrow. Some people with multiple myeloma also develop AL amyloidosis. AL amyloidosis is when proteins called light chains build up in an organ or multiple organs.

Contact a doctor if you’re experiencing any unusual symptoms. Make sure to follow up with all scheduled appointments, so a doctor can confirm your diagnosis as soon as possible. Getting a diagnosis and starting treatment early may help minimize organ damage.