Rare types of breast cancer: Around 70% of breast cancers are an invasive type of carcinomas. Oncologists have developed several ways of grouping breast cancers into different types. The rare types of breast cancers are known as “SPECIAL TYPE” whereas more common ones are termed as “NO SPECIAL TYPE”
Lymphoma of the Breast
These are a rare type of breast cancers as they make up only 1% or less in as many as 100 cases of breast cancer. Among the non-Hodgkin lymphomas (NHL) the most common types include extranodal marginal zone lymphomas and B-cell lymphomas. Peripheral T-cell lymphoma is a less common type.
Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is another rare type of NHL. It rarely develops in women who have breast implants. Seroma or swelling around the implant is the first sign, and some women may also develop a lump close to the implant. The symptoms may manifest sooner or later after breast implant surgery. If it is localized (which is otherwise called in situ), the implant is removed and no further treatment is usually needed. However, in some cases, oncologists prescribe medicines to treat it. The outlook is good. However, in infiltrative type (i-ALCL), a lump can be felt in the breast and cancer may spread to the lymph nodes as well. A breast oncoplastic surgeon removes the implant and the lymph nodes and also prescribe chemotherapy and radiotherapy.
Metaplastic Breast Cancer
This type is a heterogeneous group of invasive and aggressive breast cancer. This type of breast cancer is also very rare (less than 5%) and is common in black and Hispanic women. It usually occurs in middle-aged and older women (age 50 to 60 years and above). The treatment is the same – surgery, chemotherapy and radiotherapy. Though these cancers do not spread to the lymph nodes, they are more likely to spread to other body parts. Sometimes, these cancers are triple-negative as well.
Adenoid Cystic Carcinoma of the Breast
It is a slow-growing cribriform cancer – which is less than 1% (which means, 1 in 100 breast cancer cases are adenoid cystic cancer). Cancer develops in the breast tissue and most often diagnosed in the salivary glands. It is common in older people, but can also be seen in young women. Surgery is the best option – breast conservation surgery (lumpectomy) is performed. This type of cancer rarely spread to other parts of the body. The recurrence rate is quite low – and hence the outlook is excellent.
Tubular Breast Cancer
This type of breast cancer looks like tubes under a microscope – and hence, it is known as tubular type. It is a very rare type of cancer (less than 2%). Tubular cancer can spread to nearby lymph nodes. It is commonly detected in older women. The recurrence rate is low as it doesn’t come back after treatment. The outlook is therefore excellent.
Mucinous (Mucoid or Colloid) Breast Cancer
This rare type of breast cancer occurs very rarely (1 to 2%). The name mucinous is due to the large amount of mucin it has. Sometimes, it can be a mixture of mucinous and other types. The treatment is the same as with any other type – breast surgery (mastectomy or lumpectomy), chemotherapy and radiation therapy.
It is slow-growing cancer usually detected in older women. It doesn’t spread to lymph nodes. Oncologists may recommend sentinel node biopsy to see whether cancer has spread to the lymph nodes.
Mucinous carcinoma of the breast – colloid carcinoma (abnormal cells of the tumour float in pools of mucin (a slimy and slippery component of mucus). Accounts for 2 to 3% of breast cancers. Less aggressive type as it responds well to treatment.
The outlook for mucinous breast cancer is generally very good.
Medullary carcinoma of the breast
It is a rare type of breast cancer accounting for up to 1 – 5% of breast cancers. It occurs most commonly in younger women – especially those who have faulty BRCA 1 gene. Oncologists and pathologist identify these types of tumours by looking at the cell boundaries of cancer cells that clearly separate tumour cells from normal tissues. The tumour cells also contain white blood cells.
The medullary tumour appears like a soft, fleshy mass – low grade and less aggressive in nature and easy to treat. The treatment is the same as for other types of invasive breast cancers – surgery, medication, radiation therapy. The outlook is good.
Basal Type Breast Cancer
In this type of breast cancer, genetic changes are unique – owing to which cancer cells make large amounts of cytokeratin 5/6 protein. Hormone and targeted drug therapies don’t work with this type as mostly these types of cancers are triple-negative (They lack the receptors for HER2, Progesterone and Oestrogen). Therefore, the treatment modalities usually involve surgery, chemotherapy and radiation therapy.
Learn more about other rare types of breast cancer