Multiple myeloma is a cancer of plasma cells. A plasma cell is a special type of white blood cell in the bone marrow that, in healthy people, helps the immune system fight infections by making antibodies.

If plasma cells start growing out of control, they form a cancerous tumor called multiple myeloma (MM). Although there’s no cure for MM, appropriate treatment can bring it into remission, which means having no or few symptoms of the disease.

It can be challenging to recognize MM because its symptoms vary depending on the person. Initial stages of the disease often have no noticeable signs at all.

One of the rare signs of MM is an enlarged (swollen) tongue. This condition only occurs with MM-related amyloidosis. This happens when cancer-causing plasma creates irregular antibodies that build up in your organs, in this case, your tongue.

Keep reading to learn about the connection between an enlarged tongue, amyloidosis, and MM, including this condition’s causes, treatment, and outlook.

The term “amyloidosis” means a buildup of an abnormal protein (called amyloid) in your body.

In the case of MM, amyloid buildup happens because cancerous plasma cells make abnormal antibodies. These antibodies can stick together and form clumps in your organs, most commonly:

  • kidneys
  • heart
  • liver

Amyloidosis is not very common. It happens in 10% to 15% of people with MM.

What about tongue amyloidosis? This rare condition occurs when the antibody amyloid builds up in your tongue, making it large, swollen, and painful (macroglossia). Your tongue can sometimes look rippled around the edges. It’s more common in women over the age of 50.

Because a swollen tongue is a rare symptom of MM, you shouldn’t assume that you have this condition if you have macroglossia without any other symptoms. Pay attention for any of the following hallmark symptoms of MM, often abbreviated as CRAB:

In addition to an enlarged tongue, MM can have other oral symptoms.

Macroglossia can be associated with many different conditions. Talk with your doctor if you begin to experience swelling, pain, or other changes in your tongue. Some of the conditions that can cause an enlarged tongue include:

Your doctor may suspect MM after hearing about your symptoms and performing a physical exam. Because MM often has no symptoms in the initial stages, routine checkups with your primary doctor are important.

Your doctor will run a few tests to confirm or rule out the diagnosis of MM:

A diagnosis of MM requires:

  • a plasma cell tumor identified by biopsy OR at least 10% plasma cells in the bone marrow AND
  • at least one of the following:
    • increased calcium levels
    • kidney insufficiency
    • anemia
    • bone damage
    • increase in one type of antibody protein in the blood
    • 60% or more plasma cells in the bone marrow

Read more about MM diagnosis and the next steps.

Whether you have MM-related amyloidosis in your tongue or other parts of your body, the primary treatment targets the root cause of your symptoms — the cancerous plasma cells. A 2020 guideline on the treatment of amyloidosis in MM recommends the following:

  • high-dose chemotherapy to eliminate tumor cells in your blood, followed by an autologous stem cell transplant to replace the affected cells with your own healthy stem cells
  • the medication daratumumab, in combination with bortezomib, cyclophosphamide, and dexamethasone for people ineligible for the stem cell transplant

Supportive treatment targets the effects of amyloidosis on your body:

Doctors may additionally prescribe medications like corticosteroids to reduce the swelling in your tongue.

According to the National Cancer Institute, the 5-year relative survival rate of people diagnosed with MM is currently 58%. This means that, on average, 58% of people with MM will live at least 5 years after their diagnosis. The survival rate continues to improve as doctors learn more about managing this condition.

Unfortunately, amyloidosis can decrease your odds of survival. According to 2021 research, the median survival of people with MM-related amyloidosis was 4 years. However, it was much longer in people who started treatment at the early stages of their cancer.

Because tongue amyloidosis in MM is rare, there are no specific survival statistics for this condition.

It’s important to remember that several factors play into survival rate estimates. For example, the stage of cancer at diagnosis and which organs besides the tongue are affected by amyloidosis can change your prognosis. Talk with your doctor to determine your individual outlook.

Learn more about how doctors estimate outlook for MM.

An enlarged tongue is a rare symptom of a specific type of multiple myeloma — multiple myeloma with amyloidosis. Amyloidosis can happen if the cancerous plasma cells produce unhealthy antibodies that can stick together and build up in different parts of your body, such as the tongue.

Amyloidosis in MM is not common, and tongue amyloidosis is even less frequent. You shouldn’t assume you have MM if you develop this symptom. However, speak with your doctor because it can be a sign of several health conditions.

Doctors can treat MM-related tongue amyloidosis with surgery or drugs that target cancer cells.