Liposarcoma is a malignant tumor of fatty tissue. Like all sarcomas, it occurs relatively rarely. The fat cells do not develop in accordance with standards, whereupon the degenerated cells develop into a tumor.
Of the soft tissue sarcomas, liposarcoma is the second most common after malignant fibrous histiocytoma. Approximately 15% to 20% of soft tissue sarcomas are liposarcomas. In 1857, Rudolf Virchow was the first to describe liposarcoma as an independent clinical picture.
Epidemiology/occurrence
The tumor mostly occurs in adults, but there have also been cases (about 60 in total) in which children and adolescents have been affected. The mean age of the disease is 50 years. Liposarcoma most frequently occurs between the ages of 50 and 70.
Men are slightly more frequently affected by liposarcoma than women. The incidence is about 2.5 new cases1. 000. 000 inhabitants-year.
Causes
A clear explanation of the cause of liposarcoma formation is not yet known and is still under research. Most tumors are caused “de novo” by a degeneration of embryonic precursor cells. However, there are theories about possible causes: There is a presumption that there is a connection with previous radiation treatment with ionizing radiation. In individual cases, a liposarcoma developed from a lipoma or even from a burn scar. Whether the liposarcoma can have genetic causes has not yet been confirmed either, but it is suspected.
Localization
Most frequently, liposarcomas develop in the deep soft tissue of the lower extremity (mostly on the thigh). The second most common location is the upper extremity and the retroperitoneum. They can also occur on the trunk of the body.
In 15% to 20% of cases, metastases occur, which are most frequently located in the lungs. However, metastases can also form in the peritoneum, diaphragm, pericardium, liver, bones and lymph nodes. Liposarcoma of the thigh is particularly frequent (40%).
Those affected notice a small lump or swelling under the skin. Normally, the tumor on the thigh does not cause pain. Imaging procedures such as CT, ultrasound and MRI can provide information as to whether it is a liposarcoma or a harmless fat tumor (lipoma).
They also determine the actual size and extent of the tumor in the surrounding tissue. For a more detailed examination, a tissue sample must be taken to determine the degree of malignancy. Liposarcoma can also form in the abdominal cavity or affect the gastrointestinal tract.
Normally, the fatty tumors first develop here as painless masses and it takes longer than in other places before they are noticed and treated. Liposarcomas that occur in the abdominal cavity may grow unnoticed over a long period of time and become very large without any visible external swelling. The patient often first notices pain and sees a doctor when the tumor has already reached a considerable size and is pressing on surrounding organs or vessels in the abdomen.
The symptoms of an abdominal liposarcoma are non-specific and depend on which organs are affected. The symptoms range from abdominal pain that cannot be localized exactly, digestive problems, constipation and nausea to anemia. If the liposarcoma cannot be surgically removed because it is very large and may have grown together with other organs or large vessels in the abdomen, patients receive radiotherapy. The aim of this treatment is to reduce the size of the tumor to such an extent that it can subsequently be completely removed by surgery.
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