A lipoma is a benign fat tumour which is caused by the replication of fat cells in the subcutaneous fat tissue. In contrast to its very rare, malignant relative, liposarcoma, lipomas are relatively common. It is estimated that around 2% of people will be affected within the course of life. A lipoma only requires treatment if it is very large and unanaesthetically appealing, and irritates due to its unfavourable location.
To date, the cause of lipomas is unknown. Genetic factors also seem to play a certain role in this. On the other hand, excessive weight does not play any role in the occurrence of lipomas.
Lipomas occur predominantly in old age; however, they can in essence occur at every age. They occur most often in the subcutaneous fat tissue of the neck, back, arms, abdomen or thighs. A nodule can usually be palpable under the skin, is clearly delineated and can be displaced together with the skin. In rare cases, a lipoma may also occur in deeper-lying fat tissue of the muscles or organs. A lipoma usually grows slowly and does not cause any pain. It can range in size from just a few millimetres to several centimetres in diameter.
A lipoma is typically diagnosed on the basis of the characteristic clinical symptoms. If the tumour in question cannot be identified, a biopsy with examination of the tissue will provide information. More deeply-lying situated lipomas can sometimes require an x-ray or computed tomography.
A lipoma is benign so it does not usually need treatment. If a lipoma is unanaesthetic, very large or annoying because of where it is located (e.g. under a watch or a bra strap), it can be surgically removed. It is usually removed on an outpatient basis with a local anaesthetic.