Benign tumours

Lumps are usually referred to as tumours, and they may be benign or malignant. In a tumour, one particular type of cell (such as a glandular, fat or muscle cell) has escaped the normal controls on growth and started to multiply.

The most important characteristic is whether the tumour cells can invade other adjacent cell types, and spread around the body. Benign tumours do not invade or spread.

They can grow quite large without causing problems, although that doesn't mean they're totally harmless because their growth may start to damage the other tissues or organs around them.

This is a particular problem with a type of brain tumour called a meningioma, which grows from cells in the membranes that surround the brain (the meninges). Although benign, the pressure within the skull from the growing meningioma can cause severe headaches and may be life threatening if the tumour is not removed.

Benign tumours can cause others problems, from simply looking unsightly to releasing excess hormones.

Malignant tumours

Malignant tumours invade the tissues around them and spread to other parts of the body by sending out cancer cells into the lymphatic system or through the blood stream.

These cells are deposited in other areas of the body, particularly the lungs, liver, brain and bones, to start 'secondary' tumours (also called metastases) at the new sites. Most malignant tumours are life threatening.

Breast tumours

Women are advised to be on the look out for lumps in their breasts. However, among younger women at least, lumps are far more likely to be benign - in women under 40, more than nine out of ten breast lumps are benign. But these lumps still cause a lot of anxiety until they are sorted out.

The most common benign breast conditions are fibrocystic change, benign breast tumours and breast inflammation. These are common problems, in fact fibrocystic change used to be known as fibrocystic disease but, as it affects more than 50 per cent of women at some point, it was thought it could no longer be considered a disease.

Fibroadenomas (sometimes called breast mice because they can be moved around) are particularly common in women in their 20s or 30s. They are benign and not cancerous.

In most cases these lumps are quite harmless, although now and then they may cause troublesome symptoms such as tenderness (especially as many are influenced by hormone levels and tend to get more swollen and painful along with other menstrual symptoms).

Malignant breast tumours mostly occur in older women, and tend to be accompanied by other symptoms such as discharge from the nipple. The lump may feel craggy or irregular.

Women who have a family history of breast cancer, especially breast cancer at a young age, have an increased risk of malignant tumours.

Is it cancerous?

Sometimes it's fairly clear that a lump is either benign or malignant, but further tests may be required, including x-rays, ultrasound or biopsy. Often the best way to get an answer is to remove the whole lump and send it to the laboratory for analysis.

Benign lumps may not need to be removed but this is usually the most effective way to reassure someone because, whatever the problem, it's gone.