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 these tumour cells can invade other adjacent cell types, and spread around the body (i.e. they are malignant tumours) or not (in which case they are benign).
Benign tumours include :
- Cysts: lumps filled with fluid. Common types include sebaceous cysts on the skin, filled with greasy sebum, and ovarian cysts
- Nodules: formed in inflammatory conditions such as arthritis, sarcoid and polyarteritis
- Lipomas: lumps of fat cells
- Fibromas and fibroademonas: lumps of fibrous or fibrous and glandular tissue
- Haematoma: lump formed by blood escaping into the tissues – simply a large bruise
- Haemangioma: lump formed by extra growth of blood vessels
- Papilloma: formed from skin or internal membrane cells, for example warts.
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.