Liposarcoma is a specific form of sarcoma (malignant tumor) affecting soft tissue. This tumor is characterized as being lipomatous, that is to say a tumor developing in fatty tissue.

The severity of the disease varies from one individual to another, which can grow slowly or develop more aggressively and lead to a metastatic phase. This last phase corresponds to the development of the tumor outside its initial location. This tumor spread can be done directly or by blood circulation.

Liposarcoma is a malignant tumor, which means that the cancer can spread to other organs, including vital organs. (2)

The general locations of liposarcomas are generally at the level of the lower limbs or at the level of the retroperitoneum (part of the abdomen located behind the peritoneum, membrane lining the abdomen and viscera). However, this tumor can also be identified in the upper limbs: neck, peritoneal cavity, spermatic cord, chest, vulva or even the armpits.

It is a rare disease, the prevalence of which amounts to 1 / 100 people / year (number of cases of the disease in a given population at a given time).

It is also one of the most common soft tissue sarcomas (15 – 20% of soft tissue sarcomas are liposarcomas). (1)

The disease affects all categories of people regardless of their age. Nevertheless, its development is all the more marked in middle-aged to advanced adults (often between 40 and 60 years old). (4)

There are 4 forms of liposarcoma depending on biological parameters: (1)

– well differentiated liposarcoma;

– dedifferentiated liposarcoma;

– myxoid / round cell liposarcoma;

– pleomorphic liposarcoma.

The exact origin of the development of liposarcoma is still unknown but suspicions as to the role of chromosomal abnormalities found in certain cases of liposarcoma have been put forward.

In most cases, no symptoms are visible during the development of liposarcoma.

In some cases, swelling of the skin (in the form of “bumps under the skin”) can be identified. However, these are usually without painful consequences.

Some significant and warning signs are still to know: (2)

• the presence of persistent bumps (swelling) on ​​the skin;
• a little pain or numbness in the area of ​​the swelling;
• the presence of blood in the stools or mucous stools;
• the presence of blood during vomiting;
• abdominal pain or abdominal cramps.

In addition, the severity of the disease can be more or less important depending on the individual and the form of liposarcoma. In this sense, for the less serious forms, the associated symptoms fall within those mentioned above.

In more severe cases, the development of metastases is possible at an advanced stage of the disease. This corresponds to the progression of the tumor in other limbs, organs and tissues of the body. Metastases can then develop in vital organs and therefore be the cause of serious consequences for the patient. (4)

 This level of severity of the pathology is dependent on the form of the liposarcoma. Indeed, 4 forms of liposarcoma have been identified: (4)

• well-differentiated liposarcoma is the most common form. In this case, cancer cells are relatively similar to fat cells (adipocytes) and their multiplication is often slow;
• Myxoid liposarcoma, also called round cell liposarcoma, is a form of the disease of intermediate severity. Tumor cells appear to be characteristic under a microscope and can cause a fairly substantial level of severity;
• Pleiomorphic liposarcoma is the least frequent subtype of the disease but the level of severity is very important. Cancer cells, in these cases, are clearly identifiable and characteristic;
• Dedifferentiated liposarcoma is defined as the renewal of low-severity tumor cells into higher-severity tumor cells.

The exact origin of liposarcoma is currently still unknown.

Although some patients have experienced tumor development following injury, this is not a generality. (4)

Nevertheless, genetic abnormalities have been shown to be the cause of well-differentiated liposarcoma. In fact, 90% of the cases of well-differentiated liposarcomas would originate from an amplification of the 12q13-15 region of a chromosome. This chromosomal extension then causes overexpression of three genes involved in the development process of cells: MDM2, CDK4 and HMGA2. (3)

Liposarcoma is a very rare type of cancer affecting soft tissues.

The origin of this cancer is still unknown and scientists do not know exactly the process of development of this tumor.

However, certain factors, having a significant impact on the development of the disease, have been highlighted.

Indeed, certain genetic syndromes, exposure to radiation during the treatment of another cancer, exposure to certain chemicals and abnormalities in the lymphatic system may be additional risk factors for the development of liposarcoma. (2)

The diagnosis of liposarcoma is primarily visual, by identifying lumps in the skin of about 5 cm. (4)

The second stage of diagnosis is based on a biopsy of part of the tissue suspected of being tumor. A microscopic analysis of the collected sample makes it possible to determine the presence or not of the tumor. In the case of a strong suspicion as to the presence of tumor cells within the tissue, other examinations are carried out in order to determine, this time, the stage of progression of the cancer. These medical examinations are: (2)

• radiography;
• MRI (Magnetic Resonance Imaging);
• computed tomography;
• sonography (study by ultrasound).

General treatment of the disease involves surgery on the tumor tissue. This can be tricky if the tumor is located near vital organs. The surgery allows the cancer cells to be removed, however, in 5% of cases, an amputation is necessary for the patient to recover from the cancer and to be able to return to a more enjoyable daily life. (4)

Therapy with radiation and / or chemotherapy follows.

These means destroy cancer cells as well as reduce the risk of recurrence of the disease. In addition, radiation therapy or chemotherapy may optionally be prescribed before surgery in order to shrink the tumor. (2)

Following surgery and treatment, the patient can live a “normal” life. Nevertheless, numerous physical examinations and medical imaging examinations (MRI, Scanners, X-rays, etc.) are necessary to ensure correct patient follow-up and to prevent the development of cancer in metastatic form. (4)

The vital prognosis for liposarcoma varies depending on the form of the disease.