There are numerous causes of breast lumps, many of which are benign. Any breast lump needs a thorough assessment to exclude breast cancer.
Basic Breast Anatomy
The breasts sit in front of the chest wall, which contains the ribs and pectoral muscles. Most of the breast is adipose (fatty) tissue. The areola surrounds the nipple. Behind the nipple are the ducts, which lead into the lobules, where breast milk is produced. Milk is secreted through the ducts and out of openings on the nipple.
Breast Cancer
The most significant differential of a breast lump is breast cancer.
Triple assessment of a breast lump is standard practice to exclude or diagnose cancer. This involves:
- Clinical assessment (history and examination)
- Imaging (ultrasound or mammography)
- Histology (fine needle aspiration or core biopsy)
Clinical features that may suggest breast cancer are:
- Lumps that are hard, irregular, painless or fixed in place
- Lumps may be tethered to the skin or the chest wall
- Nipple retraction
- Skin dimpling or oedema (peau d’orange)
The NICE guidelines (updated January 2021) recommend a two week wait referral for suspected breast cancer for:
- An unexplained breast lump in patients aged 30 or above
- Unilateral nipple changes in patients aged 50 or above (discharge, retraction or other changes)
The NICE guidelines recommend also considering a two week wait referral for:
- An unexplained lump in the axilla in patients aged 30 or above
- Skin changes suggestive of breast cancer
The NICE guidelines suggest considering non-urgent referral for unexplained breast lumps in patients under 30 years.
Fibroadenoma
Fibroadenomas are common benign tumours of stromal/epithelial breast duct tissue. They are typically small and mobile within the breast tissue. They are sometimes called a “breast mouse”, as they move around within the breast tissue.
They are more common in younger women, aged between 20 and 40 years. They respond to the female hormones (oestrogen and progesterone), which is why they are more common in younger women and often regress after menopause.
On examination, fibroadenomas are:
- Painless
- Smooth
- Round
- Well circumscribed (well-defined borders)
- Firm
- Mobile (moves freely under the skin and above the chest wall)
- Usually up to 3cm diameter
Fibroadenomas are not cancerous and are not usually associated with an increased risk of developing breast cancer. Complex fibroadenomas and a positive family history of breast cancer may indicate a higher risk.
Fibrocystic Breast Changes
Fibrocystic breast changes were previously called fibrocystic breast disease. However, fibrocystic breast changes, and generalised lumpiness to the breast, is considered a variation of normal and not a disease. The connective tissues (stroma), ducts and lobules of the breast respond to the female sex hormones (oestrogen and progesterone), becoming fibrous (irregular and hard) and cystic (fluid-filled). These changes fluctuate with the menstrual cycle.
It is a benign (non-cancerous) condition, although it can vary in severity and significantly affect the patient’s quality of life if severe. It is common in women of menstruating age. Symptoms often occur prior to menstruating (within 10 days) and resolve once menstruation begins. Symptoms usually improve or resolve after menopause.
Symptoms can affect different areas of the breast, or both breasts, with:
- Lumpiness
- Breast pain or tenderness (mastalgia)
- Fluctuation of breast size
Management of fibrocystic breast changes is to exclude cancer and manage symptoms. Options to manage cyclical breast pain (mastalgia) include:
- Wearing a supportive bra
- Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen
- Avoiding caffeine is commonly recommended
- Applying heat to the area
- Hormonal treatments (e.g., danazol and tamoxifen) under specialist guidance
Breast Cysts
Breast cysts are benign, individual, fluid-filled lumps. They are the most common cause of breast lumps and occur most often between ages 30 and 50, more so in the perimenopausal period. They can be painful and may fluctuate in size over the menstrual cycle.
On examination, breast cysts are:
- Smooth
- Well-circumscribed
- Mobile
- Possibly fluctuant
Breasts cysts require further assessment to exclude cancer, with imaging and potentially aspiration or excision. Aspiration can resolve symptoms in patients with pain. Having a breast cyst may slightly increase the risk of breast cancer.
Fat Necrosis
Fat necrosis causes a benign lump formed by localised degeneration and scarring of fat tissue in the breast. It may be associated with an oil cyst, containing liquid fat. Fat necrosis is commonly triggered by localised trauma, radiotherapy or surgery, with an inflammatory reaction resulting in fibrosis and necrosis (death) of the fat tissue. It does not increase the risk of breast cancer.
On examination, fat necrosis can be:
- Painless
- Firm
- Irregular
- Fixed in local structures
- There may be skin dimpling or nipple inversion
Ultrasound or mammogram can show a similar appearance to breast cancer. Histology (by fine needle aspiration or core biopsy) may be required to confirm the diagnosis and exclude breast cancer.
After excluding breast cancer, fat necrosis is usually treated conservatively. It may resolve spontaneously with time. Surgical excision may be used if required for symptoms.
Lipoma
Lipomas are benign tumours of fat (adipose) tissue. They can occur almost anywhere on the body where there is adipose tissue, including the breasts.
On examination, lipomas are typically:
- Soft
- Painless
- Mobile
- Do not cause skin changes
They are typically treated conservatively with reassurance. Alternatively, they can be surgically removed.
Galactocele
Galactoceles occur in women that are lactating (producing breast milk), often after stopping breastfeeding. They are breast milk filled cysts that occur when the lactiferous duct is blocked, preventing the gland from draining milk. They present with a firm, mobile, painless lump, usually beneath the areola. They are benign and usually resolve without any treatment. It is possible to drain them with a needle. Rarely, they can become infected and require antibiotics.
Phyllodes tumour
Phyllodes tumours are rare tumours of the connective tissue (stroma) of the breast, occurring most often between ages 40 and 50. They are large and fast-growing. They can be benign (~50%), borderline (~25%) or malignant (~25%). Malignant phyllodes tumours can metastasise.
Treatment involves surgical removal of the tumour and the surrounding tissue (“wide excision”). They can reoccur after removal.
Chemotherapy may be used in malignant or metastatic tumours.
Last updated June 2021
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