Benign breast tumours

What benign means

Benign means non-cancerous. A benign tumour will not invade surrounding tissue and will not spread to other parts of the body. Finding a benign lump in the breast is reassuring, but it does not mean no further attention is needed. Some benign lesions need monitoring, some need biopsy to confirm they are benign, and some need surgery for other reasons.

Common types of benign breast tumours

Several different types of benign lesions can occur in the breast:

• Fibroadenoma: the most common benign breast lump, usually in younger women. Smooth, firm, and moveable. Usually does not need removal unless large or growing.
• Phyllodes tumour: a less common but important type of breast tumour that can grow rapidly and, in some cases, behave more aggressively. Needs surgical excision with clear margins.
• Lipoma: a benign collection of fatty tissue. Soft, moveable, painless. Rarely needs treatment.
• Intraductal papilloma: a small growth inside a milk duct. Often causes nipple discharge. Usually needs surgical removal to confirm the diagnosis and prevent recurrence.
• Fat necrosis: an area of dead fatty tissue, often following injury or surgery. Can feel firm and irregular but is benign. Usually resolves without treatment.

How benign breast tumours are diagnosed

Diagnosis uses a combination of clinical examination, imaging, and tissue sampling:

• Clinical examination: a trained specialist can often tell whether a lump feels benign or needs further investigation
• Ultrasound: the first imaging step in younger women. Shows whether a lump is solid or cystic and helps characterise its edges.
• Mammogram: used in older patients and as part of a triple assessment
• Core needle biopsy: gives a definitive tissue diagnosis. This is often recommended even when imaging looks benign, to be certain.

When surgery is indicated

Not all benign breast tumours need surgery. Surgery is considered when:

• The lump is growing rapidly
• The lump is large enough to cause discomfort or distortion
• The imaging or biopsy result suggests a phyllodes tumour, which always needs surgical excision
• The patient has significant anxiety about the lump and wants it removed
• The biopsy result is not fully concordant with the imaging (discordant results need further action)
• An intraductal papilloma causes persistent or blood-stained nipple discharge

When watchful waiting is appropriate

Small, stable fibroadenomas that have been confirmed by biopsy and show classic benign features on imaging can safely be monitored rather than removed. Most fibroadenomas in young women will stay the same size or shrink over time. A follow-up ultrasound at six to twelve months gives reassurance that nothing has changed.

The decision to watch and wait is made after a full assessment. It is not a guess. It is a deliberate, evidence-based choice made when the lump clearly meets criteria for a benign lesion.

Phyllodes tumours specifically

Phyllodes tumours are fibroepithelial lesions that are classified as benign, borderline, or malignant on biopsy. Even benign phyllodes tumours require surgical excision with a clear margin around the tumour. Borderline and malignant phyllodes need wider excision. If the margins are not clear, the risk of local recurrence is high. This is why phyllodes tumours are not suitable for watchful waiting.

Frequently asked questions