Definition
A lipoma is a benign fat tumor that develops from the adipose tissue or fat cells (adipocytes). It is usually enclosed in a capsule of connective tissue and thus well separated from the surrounding tissue. Lipomas are counted among the group of soft tissue tumors.
They are usually located in subcutaneous fatty tissue directly under the skin or subcutaneously (sub: underneath; cutis: skin). Sometimes, however, they may also be located in internal organs or muscles. There too, they merely represent a benign growth of the fatty tissue. If several lipomas occur simultaneously in different parts of the body, this is known as lipomatosis.
Causes
The causes for the development of lipomas are as yet unexplained. A connection to fat metabolism illnesses such as diabetes mellitus or a hypercholesterolemia (increased cholesterol values) could not be scientifically proven so far. In the context of certain hereditary diseases, lipomas can occur, but then usually spread over the whole body as for example in the case of the lipomatosis dolorosa or the neurofibromatosis. In contrast to isolated lipomas, lipomas in these diseases are usually painful or accompanied by further complications.
Frequency
There are no exact figures for the frequency of occurrence of lipomas, but it is a rather common phenomenon. It is estimated that two to three per 100 people are affected. These are usually between 30 and 60 years old.
Lipomas do not occur frequently in children. Most frequently, lipomas are localized in the head, neck, and trunk area, followed by the shoulder, back, flanks, or abdomen, and isolated lipomas are also often found on arms and legs. In post-menopausal women, lipomas can also occur in the breast.
In men, lipoma in the breast is much less common, but in principle it is also possible. Overall, men are somewhat more frequently affected than women when lipomas are considered as a whole. Lipomas in the breast are certainly an exception, since men naturally have less fatty tissue in this part of the body than women.
