Mucinous carcinoma of the breast — sometimes called colloid carcinoma — is a rare form of invasive ductal carcinoma (cancer that begins in the milk duct and spreads beyond it into nearby healthy tissue). In this type of cancer, the tumor is made up of abnormal cells that “float” in pools of mucin, a key ingredient in the slimy, slippery substance known as mucus.
Normally, mucus lines most of the inner surface of our bodies, such as our digestive tract, lungs, liver, and other vital organs. Many types of cancer cells — including most breast cancer cells — produce some mucus. In mucinous carcinoma, however, mucin becomes part of the tumor and surrounds the breast cancer cells. Under a microscope, it looks like the cancer cells are scattered throughout pools of mucus.
Research suggests that only about 2-3% of invasive breast cancers are “pure” mucinous carcinomas — meaning that this is the only type of cancer present within the tumor. About 5% of invasive breast cancers appear to have a mucinous component within them, with other types of cancer cells present as well. Mucinous carcinoma is extremely rare in men.
Although mucinous carcinoma can be diagnosed at any age, it tends to affect women after they’ve gone through menopause. Some studies have found that the average age at diagnosis is in the 60s or early 70s.
Even though mucinous carcinoma is an invasive breast cancer, it tends to be a less aggressive type that responds well to treatment. Mucinous carcinoma is less likely to spread to the lymph nodes than other types of breast cancer.
On the following pages, you can learn more about:
- Symptoms and Diagnosis of Mucinous Carcinoma of the Breast
- Treatment of Mucinous Carcinoma of the Breast
- Follow-Up Care for Mucinous Carcinoma of the Breast
To connect with others who have been diagnosed with mucinous carcinoma of the breast, visit the Breastcancer.org Discussion Board forum Less Common Types of Breast Cancer.
The medical experts for IDC Type: Mucinous Carcinoma of the Breast are:
- Jennifer J. Griggs, M.D., medical oncologist/hematologist, Division of Hematology/Oncology at the University of Michigan, Ann Arbor, MI
- Clifford Hudis, M.D., Chief, Breast Cancer Medicine Service, Memorial Sloan-Kettering Cancer Center, New York, NY
These experts are members of the Breastcancer.org Professional Advisory Board, including more than 70 medical experts in breast cancer-related fields.