What is it ?
Liposarcoma is a particular form of sarcoma (malignant tumor) affecting the soft tissues. This tumor is characterized as being lipomatous, ie a tumor developing in the fatty tissues.
The severity of the disease varies from one individual to another who may grow slowly or develop more aggressively and end up in a metastatic phase. This last phase corresponds to the development of the tumor outside of its initial location. This tumor spread can be done directly or via the bloodstream.
Liposarcoma is a malignant tumor, which means that the cancer can spread to other organs including vital organs.
The general locations of liposarcomas are generally in the lower limbs or retroperitoneum (part of the abdomen 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 armpit.
It is a rare disease with a prevalence of 1/100 000 people / year (number of cases of the disease in a given population, at a given time).
In addition, it is one of the most common soft tissue sarcomas (15 – 20% of soft tissue sarcomas are liposarcomas).
The disease affects all categories of people, whatever their age. Nevertheless, its development is even more marked in middle-aged to advanced adults (often between 40 and 60 years old).
There are 4 forms of liposarcoma according to biological parameters:
– well differentiated liposarcoma;
– dedifferentiated liposarcoma;
– myxoid / round-cell liposarcoma;
– the pleomorphic liposarcoma.
The exact origin of the development of liposarcoma is still unknown, but suspicions about the role of chromosomal abnormalities found in some cases of liposarcomas have been put forward.
Symptoms of liposarcoma
In most cases, no symptoms are visible during the development of liposarcoma.
In some cases, skin swellings (in the form of “bumps under the skin”) are identifiable. However, these are usually painless.
Some significant and alert signs are still to know:
- persistent bumps (swellings) in the skin
- small pain or numbness in the area of swelling
- the presence of blood in the stools or mucous stools;
- the presence of blood during vomiting;
- abdominal pain or abdominal cramps.
Moreover, the severity of the disease may be more or less important depending on the individual and the form of the liposarcoma. In this sense, for the less severe forms, the associated symptoms are of those mentioned above.
In more severe cases, the development of metastases is possible at an advanced stage of the disease. This corresponds to a progression of the tumor within other limbs, organs and tissues of the body. The metastases can then develop within vital organs and thus be at the origin of serious consequences for the patient.
This level of severity of the pathology is dependent on the shape of the liposarcoma. Indeed, 4 forms of liposarcoma have been identified:
- the well-differentiated liposarcoma is the most common form. In this case, the cancer cells are relatively similar to the fat cells (adipocytes) and their multiplication is often slow;
- Myxoid liposarcoma, also called round-cell liposarcoma, is a form of disease of intermediate severity. Tumor cells appear to be characteristic under the microscope and can cause a fairly severe level of severity;
- Pleiomorphic liposarcoma is the subtype of the less common disease but the severity of which is very important. Cancer cells, in these cases, are clearly identifiable and characteristic;
- the dedifferentiated liposarcoma is defined during the renewal of low-grade tumor cells into tumor cells of greater severity.
The origins of the disease
The exact origin of liposarcoma is currently still unknown.
Although some patients have developed tumor development following an injury, this is not a generality.
Nevertheless, genetic abnormalities have been shown to be the cause of well-differentiated liposarcoma. Indeed, 90% of cases of well differentiated liposarcomas originate from an amplification of the 12q13-15 region of a chromosome. This chromosomal extension then causes an over-expression of three genes involved in the cell development process: MDM2, CDK4 and HMGA2.
Risk factors for liposarcoma
Liposarcoma is a very rare type of cancer that affects soft tissue.
The origin of this cancer is still unknown and scientists are not exactly aware of the development process of this tumor.
However, some factors, having a significant impact on the development of the disease, have been highlighted.
Indeed, some genetic syndromes, exposure to radiation when treating another cancer, exposure to certain chemicals and abnormalities in the lymphatic system may be additional risk factors for the development of liposarcoma.
Prevention and treatment of liposarcoma
The diagnosis of liposarcoma is primarily visual, by the identification of bumps in the skin of about 5 cm.
The second stage of the diagnosis is based on a biopsy of part of the tissue suspected to be tumor. Microscopic analysis of the sample taken to determine the presence or absence 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:
- MRI (Magnetic Resonance Imaging);
- computed tomography;
- sonography (study by ultrasounds).
The general treatment of the disease results in surgery on the tumor tissue. This can be tricky if the tumor is near vital organs. Surgery allows the removal of cancer cells, however, in 5% of cases, an amputation is necessary for the patient to cure cancer and can find a more appreciable daily life.
Radiation and / or chemotherapy follow.
These means can destroy cancer cells and reduce the risk of recurrence of the disease. In addition, radiotherapy or chemotherapy may be prescribed before surgery to shrink the tumor.
Following surgery and treatment, the patient can live a “normal” life. Nevertheless, many physical examinations and examinations of medical imaging (MRI, Scanners, X-rays, etc.) are necessary to ensure a correct follow-up of the patient and to avoid the development of cancer in metastatic form.
The life-course relative to liposarcoma varies according to the form of the disease.