Un lipome is a benign tumor made up of fat which usually does not cause any complications. It is above all embarrassing for the person affected aesthetically when it is located at the level of the skin. The origin of this type of tumor is not well known. This pathology mainly affects adults between 40 and 60 years. Treatment, when necessary, is surgery.

It comes in the form of a soft ball to the touch. The fat present inside is exactly the same as normal subcutaneous fat. Variable in size, it can appear on different parts of the body: in particular on the neck, torso, arms or breasts, when it comes to a cutaneous lipoma. But it can exist almost anywhere inside the body (stomach, lungs, brain, liver, etc.). It is a benign tumor that develops gradually. Unlike malignant tumors, cells in a lipoma do not migrate to other organs and do not metastasize. They are most often small, and 80% of them are less than 5 cm, the others do not exceed 10 cm.

Types of lipomas and their variants:

• Subcutaneous lipomas : tumors that look like soft balls of fat under the skin. It is the most frequent form.
• Other benign lipomas are much less common. It can be:
  • Fibrolipomas.
  • Benign mesenchymoma.
  • Lipoblastoma: occurring in infants or children under 3 years old.
  • Pleomorphic lipoma: especially in men over 45 years old.

• Heterotopic lipomas: these are lipomas containing fat cells associated with other types of cells, from other tissues. They may be intramuscular lipomas, arborescent lipomas, neural fibrolipomas, parosteal lipomas, etc.
• Hibernomes : These are lipomas formed from a particular fat, brown fat.
• Malignant tumors of the lipoma family.

  They are much rarer than benign lipomas:

  • Liposarcoma which can be well differentiated, or dedifferentiated.
  • Myxoid liposarcoma.
  • Pleomorphic liposarcoma.

Causes

When a lipoma occurs, it is because fat cells or adipocytes have multiplied there. The origin of this proliferation of fat-storing cells remains unexplained. the genetic factor (heredity) would seem to play a role in their occurrence, but the triggering mechanism and other factors involved are not known. Their evolution towards spontaneous healing is also a mystery.

Some people can have lipomatose : they present in this case several lipomas on the body.