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Sidney Kimmel Cancer Center / Centers & Clinics

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Mucinous (Colloid) Breast Cancer

Mucinous (Colloid) Breast Cancer Diagnosis

Mucinous breast cancer, also called colloid breast cancer, is a rare type of invasive ductal breast cancer that accounts for less than 2% of all breast cancers.  Like other types of invasive ductal cancer, mucinous breast cancer begins in the milk duct of the breast before spreading to the tissues around the duct.

When the cells of a mucinous breast cancer are examined under a microscope, there is an unusually large amount of mucous, or mucin, which makes up part of the tumor and gives the cancer its name. A tumor may contain both mucinous breast cancer cells and more typical invasive ductal cells and treatment is recommended based on the tumor makeup as a whole.

Mucinous tumor cells tend to behave less aggressively than more typical kinds of invasive ductal cancer. They are usually low grade, meaning that they are not dividing very quickly, and look more like normal cells.  They are usually positive for the estrogen and/or progesterone receptors (ER/PR+) and negative for the HER2 receptor (HER2-).  Mucinous tumor cells are less likely to involve the lymph nodes, are more responsive to treatment, and may have a better prognosis than more common types of invasive ductal cancer.

Mucinous (Colloid)  Breast Cancer Treatment

Local therapy is aimed at preventing the cancer from coming back in the breast. Local therapy includes surgery (lumpectomy or mastectomy), and may include radiation. 

Systemic therapy is used to prevent the disease from coming back or spreading to another part of the body.  This may include endocrine (hormone) therapy, chemotherapy, and therapy that targets the HER2 protein.  Often different types of treatment are used together to achieve the best result.

Your treatment plan will be based on the features of the tumor (type of cells, tumor grade, hormone receptor status, and HER2 status) and the stage of the disease (tumor size and node status). Your oncology team will recommend a treatment plan based on what is known about mucinous breast cancer in general and tailored to your specific disease.

We know that it can be stressful to receive a diagnosis of breast cancer, and learning that you have a rare form of the disease can add to your anxiety.  We hope it will be reassuring to know that our team at the Center for Rare Breast Tumors is dedicated to latest research and treatment of mucinous breast cancer, and is here to support patients and their families through diagnosis, treatment, and survivorship.