Non-cancerous tumours of the breast

A non-cancerous (benign) tumour of the breast is a growth that does not spread (metastasize) to other parts of the body. Non-cancerous tumours are not usually life-threatening. They are typically removed with surgery and do not usually come back (recur).

The following are non-cancerous tumours of the breast.

Fibroadenomas are made up of connective and gland tissues. They are common in young women between 20 and 30 years of age. One or several fibroadenomas can occur, and they can develop in one or both breasts. Most fibroadenomas are 1–2 cm in size, but they can grow as large as 5 cm.

Simple fibroadenomas are the most common type of fibroadenoma. They are made up of one type of tissue. Simple fibroadenomas don’t increase the risk for breast cancer.

Complex fibroadenomas are made up of different tissues, including cysts, calcifications and enlarged groups of glands that make milk (called lobules). Having a complex fibroadenoma slightly increases the risk for developing breast cancer.

A fibroadenoma is usually found as a lump in the breast. The lump feels rubbery or smooth, it is easy to move in the breast tissue and it has well-defined edges.

A fibroadenoma usually doesn’t need to be treated. If it grows over time or changes the shape of the breast, doctors may do surgery to remove it.

An intraductal papilloma is a wart-like tumour that develops in a breast duct. They are usually found close to the nipple. Both women and men can develop an intraductal papilloma, but it is more common in women.

Most intraductal papillomas do not increase your risk of developing breast cancer. But if there is a type of abnormal cell growth (called atypical hyperplasia), your risk may be slightly higher. Your risk for breast cancer may also be a bit higher if you have several intraductal papillomas.

The most common symptom of an intraductal papilloma is nipple discharge, which can be clear or bloody. Sometimes a lump can be felt near or under the nipple. Some people may have pain in the area.

Phylloides tumours may also be called phyllodes or cystosarcoma phylloides. They start in the connective and gland tissues of the breast.

Almost all phylloides tumours are non-cancerous. In rare cases, a phylloides tumour may be cancerous. Other phylloides tumours are classified as borderline, or uncertain malignant potential, tumours. This means that doctors can’t tell if the phylloides tumour is, or will become, cancerous.

A phylloides tumour can cause a firm round lump. Sometimes it can cause pain. Phylloides tumours often grow very quickly, and they may be quite large when they are diagnosed.

Doctors will do surgery (called a lumpectomy) to remove a phylloides tumour. They remove a wide area of normal breast tissue around the tumour (called the surgical margin) because these tumours tend to come back (recur) if all of the tumour isn’t removed. They may need to do a mastectomy for large cancerous phylloides tumours or phylloides tumours that recur.

The following are rare non-cancerous tumours that can start in different breast tissues:

• lipoma
• hemangioma
• hamartoma
• adenoma
• neurofibroma
• granular cell tumour