Mucinous Carcinoma

Mucinous carcinoma is a rare type of cancer. It starts in the main cells of mucus, called mucin. Although this type of cancer can develop anywhere, it’s most common in your breast. Mucinous carcinoma is often less aggressive than other cancer types and responds well to treatment.


What is mucinous carcinoma?

Mucinous carcinoma is a rare type of cancer. In mucinous carcinoma, cancer cells form in mucin, the main component of mucus. Mucins are proteins that help with the function of healthy cells. In mucinous carcinoma, the mucin around cancer cells becomes part of the tumor.

Mucinous carcinoma can occur anywhere in your body, but it’s most common in your breast. When mucinous carcinoma occurs in your breast, it’s called colloid carcinoma. Mucinous carcinoma may also form in your lungs, colon or rectum.


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What’s the difference between pure and mixed mucinous carcinoma?

Sometimes, the mucinous cancer cells are the only cancer cells present. This type is called pure mucinous carcinoma.

These mucin-surrounded cancer cells can also form along with other types of cancer cells. When this occurs, it’s called mixed mucinous carcinoma.

What’s the difference between mucinous carcinoma and adenocarcinoma?

Adenocarcinoma starts in your mucous glands. Your mucous glands are clusters of mucous cells in the mucous membrane, which lines your digestive tract. With adenocarcinoma, people often produce too much mucin.

Mucinous carcinoma starts in the mucin, the protein that surrounds all cells. This type of cancer involves the mucin, which becomes part of the tumor.


How common is mucinous carcinoma?

Mucinous carcinoma is rare. It’s most common in breast cancer, accounting for about 7% of cases. It also accounts for:

Symptoms and Causes

What causes mucinous carcinoma?

In general, cancer forms when your body’s cells don’t break down or grow as usual. Healthcare providers don’t know exactly what causes cancer. Some factors that can affect your risk include:

  • Age: Your risk of developing certain cancers, such as breast cancer, increases as you get older.
  • Environment: Exposure to secondhand smoke or certain chemicals can increase risk.
  • Family history: If one of your family members had cancer, you might be more likely to develop cancer.
  • Genetics: Certain gene changes (mutations) can increase your cancer risk.
  • Lifestyle: Drinking alcohol, eating a low-fiber diet and having a sedentary lifestyle can be risk factors for certain cancers.


What are the symptoms of mucinous carcinoma?

Mucinous carcinoma symptoms are similar to symptoms of other cancer types. The first sign of mucinous carcinoma in your breast may be a lump in your breast tissue. You may also have:

Mucinous carcinoma can also form in your colon or rectum. The symptoms are similar to other types of colorectal cancer, including:

Mucinous carcinoma in your lungs may cause:

Diagnosis and Tests

How is mucinous carcinoma diagnosed?

To diagnose mucinous carcinoma, your healthcare provider may use:

  • Imaging tests, such as an ultrasound, MRI or CT scan.
  • Mammogram, an imaging tool to evaluate breast tissue.
  • Biopsy, a procedure to take a small tissue sample to examine in a lab.

Management and Treatment

How is mucinous carcinoma treated?

Mucinous carcinoma treatment depends on the cancer type and stage and your overall health. In cancer staging:

  • Stage I, II or III mean you have cancer in one part of your body. The higher the stage, the more cancer has spread to surrounding tissues.
  • Stage IV means cancer has spread (metastasized) to other, distant parts of your body.

Mucinous carcinoma is often less aggressive than other cancer types. Oncologists (cancer doctors) may treat it with:

  • Hormone therapy to reduce your estrogen (female hormone) levels. This treatment is often effective for mucinous carcinoma of the breast.
  • Surgery to remove cancer cells.
  • Chemotherapy, taking medications that destroy cancer cells.
  • Radiation therapy to kill or slow the growth of cancer cells.
  • Targeted therapy, taking drugs that identify and attack specific parts of cancer cells.
  • Immunotherapy, or medications that help your immune system detect and destroy cancer cells.


How can I reduce my risk of mucinous carcinoma?

There’s no guaranteed way to prevent mucinous carcinoma. You can reduce your risk of developing any cancer by following a healthy lifestyle:

  • Achieve and maintain an optimal weight for your sex, age and body type.
  • Eat a nutritious diet with fruits, vegetables, healthy fats, lean protein and whole grains.
  • Exercise regularly, incorporating both strength training and aerobic exercise.
  • Limit your intake of alcohol and processed meats.
  • Practice safe behaviors, including safe sex and refraining from drug use or needle sharing.
  • Quit smoking.

Outlook / Prognosis

What is the prognosis for mucinous carcinoma?

Many mucinous carcinomas are treatable. They’re usually less aggressive than other types of cancer. They don’t spread as quickly to your lymph nodes or other tissues.

With all types of cancer, the earlier you get treatment, the better your chances of a positive outcome. Pure mucinous carcinoma typically has a better prognosis than mixed mucinous carcinoma. In one study, the five-year survival rate of pure mucinous carcinoma was nearly 100%.

After any cancer treatment, you’ll need regular follow-ups with your healthcare provider. These visits monitor your overall health and help healthcare providers detect and treat cancer promptly if it does return (recurs).

Living With

What questions should I ask my doctor if I’m diagnosed with mucinous carcinoma?

You may want to ask your healthcare provider:

  • Do I have pure or mixed mucinous carcinoma?
  • What tests do I need to diagnose mucinous carcinoma?
  • What are the treatment options?
  • What are the chances that mucinous carcinoma will return after treatment?

Additional Common Questions

Is mucinous breast cancer aggressive?

Mucinous carcinoma in the breast, especially pure mucinous carcinoma, is usually less aggressive than other types of breast cancer.

Can mucinous carcinoma spread?

Yes. Mucinous carcinoma can spread to surrounding tissues or other parts of your body. But it’s less likely to spread than other types of cancer cells.

A note from Cleveland Clinic

Mucinous carcinoma is a rare type of cancer. It can develop anywhere, but is most common in your breast. It may also form in your lungs, colon or rectum. Mucinous carcinoma causes symptoms similar to other types of cancer. It’s usually less aggressive, though, and less likely to metastasize (spread) to your lymph nodes. When your healthcare provider finds mucinous carcinoma in its early stages, it usually responds well to treatment.

Medically Reviewed

Last reviewed on 05/02/2022.

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