Mucinous carcinoma of the breast

Mucinous carcinoma of the breast

Mucinous carcinoma of the breast, sometimes called colloid carcinoma, is a rare form of invasive ductal carcinoma (cancer that begins within the dairy duct and spreads outside of it). Mucinous carcinoma of the breast accounts for about 2-3% of all cases of breast cancer. In this type of cancer, the tumor is formed from abnormal cells that "float" in accumulations of mucin, one of the main components of the slippery viscous substance known as mucus.
Commonly, this mucus covers most of the internal surfaces of the human body, including the digestive tract, the lungs, the liver, and other vital organs. Many types of cancer cells (including most breast cancer cells) produce this mucus. However, in mucinous carcinoma, mucus becomes a major part of the tumor and surrounds breast cancer cells.
Mucinous carcinoma usually affects postmenopausal women. Some studies indicate that the average age at diagnosis is 60 years or more.
Mucinous carcinoma is less likely to spread to lymph nodes than other types of breast cancer. It is also easier to treat.

Symptoms and diagnosis of mucinous carcinoma of the breast : 

In this section, you can read about the symptoms of mucinous carcinoma and the different methods available to diagnose it.

Signs and symptoms

Like other types of breast cancer, mucinous carcinoma of the breast may not cause any symptoms at first. Over time, a lump may be large enough to be palpated during self-examination or examination by the doctor. Tumors usually measure between 1 cm and 5 cm.

Diagnosis:

The diagnosis of mucinous carcinoma usually involves a series of steps:

A physical examination of the breasts. The doctor can feel the lump in the breast or you can feel it yourself during a self-examination.

A mammogram to locate the tumor and look for signs of cancer in other areas of the breast. Mammography may detect a mucinous carcinoma, but it usually appears as a benign (non-cancerous) breast lump. Mucinous carcinoma has well-defined borders and exerts pressure against healthy surrounding breast tissue, but does not invade it (it does not multiply inside).

An ultrasound uses sound waves to obtain images of breast tissue.
An MRI obtains more images of the breasts and detects the presence of cancer in other areas.

A biopsy involves making a small incision and removing the entire tumor or using a special needle to remove tissue samples from the potentially affected area with a microscope. A biopsy is a key to an accurate diagnosis since diagnostic imaging tests alone do not distinguish mucinous carcinoma from other types of breast cancer or from benign breast lumps.

When the pathologist examines the tissue with a microscope, he looks for small clusters of tumor cells that seem to "float" in mucin accumulations. The tumor may be formed primarily of mucin or may be formed primarily of cancer cells separated by small amounts of mucin.

Mucinous carcinoma can also be found near other types of breast cancer more common or combined with them. Occasionally, an in situ ductal carcinoma (DCIS, cancer that has not spread outside the milk duct) is found near the mucinous carcinoma. A mucinous carcinoma may also have some areas inside that contain invasive ductal carcinoma cells. If invasive ductal carcinoma cells form more than 10% of the tumor, the cancer is known as "mixed" mucinous carcinoma. Mucinous carcinoma is "pure" when at least 90% of the cells are mucinous.

As with other rare cancer subtypes, the diagnosis of mucinous carcinoma requires specific expertise. It is convenient that you seek a second opinion if you receive this diagnosis.

Pure mucinous carcinoma has other key features:

Positive hormone receptors: research indicates that pure mucinous carcinoma has positive estrogen receptors in 90-100% of cases and positive progesterone receptors in 50-68% of cases.

HER2 negative: Mucinous carcinoma usually has HER2 / neu negative protein receptors.

Negative lymph nodes: Pure mucinous carcinoma rarely spreads to the lymph nodes, especially if the tumor is 1-2 cm or less. In the case of larger tumors, there may be spread to the lymph nodes. Occasionally, lymph node cancer indicates that the tumor is actually a mixed mucinous carcinoma, with the presence of invasive ductal carcinoma cells...

Treatment for mucinous carcinoma of the breast:

You and your doctor should work together to agree on a treatment plan for mucinous carcinoma of the breast. Pure mucinous carcinoma is easier to treat than invasive ductal carcinoma, so it does not require so much treatment, especially if the tumor is small and cancer has not spread to the lymph nodes.

The plan may include:

Surgery to remove cancer and the affected lymph nodes. The following are possible procedures:

Lumpectomy: The surgeon removes only the part of the breast that has the tumor and some of the normal tissue that surrounds it. The doctor can also remove some of the lymph nodes.

Simple or total mastectomy: removal of the breast without removing the axillary lymph nodes. A sentinel lymph node biopsy is performed to analyze the node or nodes near the tumor for signs of cancer spread.

Modified radical mastectomy: surgery that aims to remove the breast, the lining of the chest wall and part of the axillary lymph nodes. Because pure mucinous carcinoma usually does not spread outside the original tumor, this type of mastectomy is not very common.

Adjuvant (additional) therapy, such as hormone therapy or chemotherapy.

Hormone therapy involves the administration of medications, such as tamoxifen or an aromatase inhibitor, that block the effects of estrogen or reduce the concentration of estrogen in the body. Almost all mucinous carcinomas have positive estrogen receptors, so hormone therapy is very likely to be effective. Adjuvant hormone therapy is given to reduce the risk of cancer coming back.

Chemotherapy involves the administration of anticancer drugs in the form of tablets or directly through a vein. Medications are distributed to all parts of the body through the bloodstream. The main objective is to destroy cancer cells that could have spread from the original tumor. At present, it is still discussed whether additional treatment is really necessary in cases of pure mucinous carcinoma.

Many doctors make recommendations on adjuvant therapy for tubular carcinoma based on the size of the tumor and whether or not there are signs of cancer in the lymph nodes. Keep in mind that each doctor may have a different opinion about whether or not an additional treatment for mucinous carcinoma. Below are some general guidelines.

If the tumor size is less than 1 cm, without the presence of cancer cells or with a very small amount of them in a lymph node: Hormone therapy may be used, but no other treatment is needed after surgery.

If the size of the tumor is 1 to 2.9 cm, without the presence of cancer cells or with a very small amount of them in a lymph node: chemotherapy can be contemplated in combination with hormone therapy.

If the tumor size is 3 cm or larger and there is spread to the lymph nodes: chemotherapy is recommended in most cases, in combination with hormone therapy.

You can analyze with your doctor all the risks and benefits of performing another treatment in addition to surgery. The final decision will depend on what you and your doctor consider best for your case.

Most mucinous carcinomas have negative HER2 / neu protein receptors, so they are not usually treated with Herceptin (generic name: trastuzumab). However, be sure to confirm with your doctor if this medication (which acts on HER2 receptors) is recommended for your case.