Rare breast cancer types

This page was reviewed under our medical and editorial policy by

Daniel Liu, MD, Plastic and Reconstructive Surgeon

This page was reviewed on February 18, 2022.

Rare breast cancers differ from other types of breast cancer in their signs and symptoms. They also vary by outlook and treatment regimens.

Rare cancer types affecting the breast

Inflammatory breast cancer

Inflammatory breast cancer (IBC) is a rare type of breast cancer often starts in the soft tissues of the breast and causes the lymph vessels in the skin of the breast to become blocked. As a result, the breast may become firm, tender, itchy, red and warm due to increased blood flow and a build-up of white blood cells. This type of cancer is distinct from other types, with major differences in symptoms, prognosis and treatment.

The term “inflammatory” refers only to the appearance of the breasts. When breasts become inflamed due to an infection or injury, they often become tender, swollen, red and itchy. However, the underlying cause of IBC is unrelated to inflammation.

Because of the similarities in symptoms, IBC may at first be diagnosed as a breast infection, such as mastitis. However, although antibiotics will resolve a breast infection, they cannot treat IBC. If your doctor prescribes antibiotics and your symptoms do not resolve within seven to 10 days, this may be a sign that you have IBC.

IBC tends to grow quickly and aggressively and is typically diagnosed when it is already in an advanced stage of breast cancer, most often stage 3B or stage 4.

Inflammatory breast cancer treatment options: Treatment of IBC typically includes breast cancer chemotherapy, followed by surgery (breast-conserving surgery or total mastectomy) and radiation therapy. Additional therapy, such as hormone therapy and/or additional chemotherapy, may also be given. Learn more about advanced treatments for breast cancer.

Learn more about inflammatory breast cancer

Metastatic breast cancer

Metastatic breast cancer, also known as stage 4 or advanced breast cancer, is breast cancer that has spread to other organs in the body. Metastases from breast cancer may be found in lymph nodes in the armpit, or they can travel anywhere in the body. Common sites include distant organs like the lung, liver, bone and brain. Even after an original tumor is removed, microscopic tumor cells may remain in the body, which allows the cancer to return and spread.

Patients may initially be diagnosed with metastatic disease, or they may develop metastases months or years after their initial breast cancer treatment. The risk of breast cancer returning and metastasizing varies from person to person and depends greatly on the biology of the tumor and the stage at the time of the original diagnosis.

Treatment for metastatic breast cancer includes many of the same treatments as other stages of breast cancer:

  • Chemotherapy
  • Hormone therapy
  • Radiation therapy
  • Targeted therapy
  • Surgery

These treatments may be given alone or in combination.

Learn more about metastatic breast cancer

Male breast cancer

Male breast cancer occurs when malignant cells form in the tissues of the breast. Any man can develop breast cancer, but it is most common among men who are 60 to 70 years old. About 1 percent of all breast cancers occur in men. About 2,800 men are diagnosed with breast cancer each year.

Many men may be surprised to learn they can get breast cancer. Men have breast tissue that develops in the same way as breast tissue in women and is susceptible to cancer cells in the same way. In girls, hormonal changes at puberty cause female breasts to grow. In boys, hormones made by the testicles prevent the breasts from growing. Breast cancer in men is uncommon because male breasts have ducts that are less developed and are not exposed to growth-promoting female hormones.

Just like in women, breast cancer in men may begin in the ducts and spread to surrounding cells. More rarely, men may develop inflammatory breast cancer or Paget’s disease of the breast, if a tumor that began in a duct beneath the nipple moves to the surface. Male breasts have few if any lobules, and so lobular carcinoma rarely, if ever, occurs in men.

Men should also be aware of gynecomastia, the most common male breast disorder. Gynecomastia is not a form of cancer but does cause a growth under the nipple or areola that can be felt, and sometimes seen. Gynecomastia is common in teenage boys due to hormonal changes during adolescence, and in older men, due to late-life hormonal shifts. Certain medications can cause gynecomastia, as can some conditions, such as Klinefelter syndrome. Rarely, gynecomastia is due to a tumor. Any such lumps should be examined by your doctor.

Male breast cancer treatment typically consists of mastectomy, followed by radiation therapy, chemotherapy, hormone therapy and/or targeted therapy. Since many male breast cancers are hormone receptor-positive, the drug tamoxifen (Nolvadex®) is often a standard therapy for male breast cancer.

For men whose cancer has not spread to the lymph nodes, adjuvant therapy (therapy given after surgery) is generally the same as for a woman with breast cancer. For men whose cancer has spread to the lymph nodes, adjuvant therapy may include chemotherapy plus tamoxifen and/or other hormone therapy. Treatment for men with cancer that has spread to other parts of the body may include hormone therapy and/or chemotherapy.

Learn more about male breast cancer

Paget's disease of the breast

Paget’s disease of the breast is a form of breast cancer that causes distinct skin changes on the nipple. A rare disease, accounting for fewer than 3 percent of all breast cancers, it is named for Sir James Paget, the English surgeon who first documented the condition in 1874. Under a microscope, Paget’s cells look very different from normal cells, and divide rapidly. About half of the cells test positive for estrogen and progesterone receptors, and most test positive for the HER2 protein. Although women with Paget’s disease of the breast sometimes have tumors inside the breast tissue, its most noticeable symptoms involve changes to the skin of the nipple or areola (the darker, circular area around the nipple of the breast), creating oozing or the appearance of eczema. The cancer is typically diagnosed with a biopsy of the tissue, sometimes followed by a mammogram, sonogram or MRI to confirm the diagnosis. Paget’s disease of the breast is not related in any medical way to other conditions named after Sir James Paget, such as Paget’s disease of the bone.

The main symptoms of Paget’s disease of the breast are superficial skin changes, limited to the nipple or areola, that are sometimes mistakenly dismissed as innocuous. Those symptoms include:

  • A skin rash on the nipple or areola, resembling eczema, with the skin developing flakiness, redness or itchiness
  • Discharge from the nipple
  • A burning, painful or tingling sensation, especially in advanced stages of the disease
  • Nipple changes, such as inverted nipples
  • Changes to the breast, such as a lump, redness, oozing, crustiness or a sore that doesn’t heal

The primary treatment for Paget’s disease of the breast is most often the surgical removal of the tumor. Cancers that are diagnosed in the early stages may be treated with breast-conserving lumpectomy, while more advanced malignancies may require a mastectomy.

As with other breast cancers, your care team may recommend chemotherapy, radiation therapy or other treatments for Paget’s disease of the breast. Learn more about advanced treatments for breast cancer.

Learn more about Paget's disease of the breast

Rare forms of invasive ductal carcinoma

While invasive ductal carcinoma is generally common, below are four types of invasive ductal carcinoma that are less common:

Medullary ductal carcinoma: This type of cancer is rare and accounts for 3 percent to 5 percent of breast cancers. It is called “medullary” because, under a microscope, it resembles part of the brain called the medulla. Medullary carcinoma may occur at any age, but it typically affects women in their late 40s and early 50s. Medullary carcinoma is more common in women who have a BRCA1 gene mutation. Medullary tumors are often “triple-negative,” which means they test negative for estrogen and progesterone receptors and for the HER2 protein. Medullary tumors 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.

Surgery is typically the first-line treatment for medullary ductal carcinoma. A lumpectomy or mastectomy may be performed, depending on the location of the tumor. Chemotherapy and radiation therapy for breast cancer may also be used.

Mucinous ductal carcinoma: This type of breast cancer accounts for less than 2 percent of breast cancers. Microscopic evaluations reveal that these cancer cells are surrounded by mucus. Like other types of invasive ductal cancer, mucinous ductal carcinoma begins in the milk duct of the breast before spreading to the tissues around the duct. Sometimes called colloid carcinoma, this cancer tends to affect women who have gone through menopause. Mucinous cells are typically positive for estrogen and/or progesterone receptors and negative for the HER2 receptor.

Surgery is typically recommended to treat mucinous ductal carcinoma. A lumpectomy or mastectomy may be performed, depending on the size and location of the tumor. Adjuvant therapy, such as radiation therapy, hormonal therapy and chemotherapy, may also be required. Because most mucinous carcinomas test negative for receptors for the protein HER2, they aren’t typically treated with trastuzumab (Herceptin®).

Papillary ductal carcinoma: This cancer is also rare, accounting for less than 1 percent of invasive breast cancers. In most cases, these types of tumors are diagnosed in older, postmenopausal women. Under a microscope, these cells resemble tiny fingers or papules. Papillary breast cancers are typically small, and test positive for the estrogen and/or progesterone receptors and negative for the HER2 receptor. Most papillary carcinomas are invasive and are treated like invasive ductal carcinoma.

Surgery is typically the first-line treatment for papillary breast cancer. A lumpectomy or mastectomy may be performed, depending on the size and location of the tumor. After surgery, adjuvant therapy may be required, including radiation, chemotherapy and/or hormone therapy.

Tubular ductal carcinoma: Another rare type of IDC, this cancer makes up less than 2 percent of breast cancer diagnoses. Like other types of invasive ductal cancer, tubular breast cancer originates in the milk duct, then spreads to tissues around the duct. Tubular ductal carcinoma cells form tube-shaped structures. Tubular ductal carcinoma is more common in women older than 50. Tubular breast cancers typically test positive for the estrogen and/or progesterone receptors and negative for the HER2 receptor.

Treatment options for tubular ductal carcinoma depend on the aggressiveness of the cancer and its stage. Treatment often consists of surgery, which includes a lumpectomy or mastectomy, and additional (adjuvant) therapy, which may include chemotherapy, radiation and/or hormone therapy. 

Next topic: What is metastatic breast cancer?

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