Dr Sylvie Bonvalot


Sarcomas are a large and diverse family of rare and complex tumors. They affect men and women of all ages and usually present as a deep mass, mainly in the limbs or the abdomen. If in the slightest doubt, it is essential to quickly consult a medical practitioner, who will refer the patient to an expert sarcoma center like Institut Curie.

The exams, diagnosis and treatment must be carried out by trained professionals to ensure a positive prognosis for this cancer. Scientists have joined forces in international networks to improve understanding of the biology of these various tumors, which has helped a great deal in the search for new treatments. Radiotherapy and surgery techniques dedicated to sarcomas have also made great progress, and the development of so-called “targeted” treatments provides very promising new therapeutic perspectives.


What is a sarcoma?

A sarcoma is a group of multiple cancerous tumors that develop from cells in the body’s supporting tissues. They may be tumors in the “soft tissue” (in the adipose tissue, the muscles or the vessels, but may also be visceral, in the stomach and colon, for example) and in the “hard” parts (bone and cartilage) of the body.

Sarcomas cannot be easily described in a few lines. Not only are they located in very diverse areas of the body, but there are at least 50 kinds, with very different molecular types and characteristics.


Soft tissue sarcomas

Soft tissue and visceral sarcomas are the most common types. The current classification of sarcomas gives them the name of the tissue that they resemble.

  • Fatty tissue: liposarcoma
  • Fibrous tissue (tendons and ligaments): fibrosarcoma
  • Muscles of the skeleton: rhabdomyosarcoma
  • Smooth muscles: leiomyosarcoma
  • Blood vessels: angiosarcoma
  • Dermis: dermatofibrosarcoma
  • Nerves: malignant tumors in the sheaths of the peripheral nerves
  • Walls of the digestive system: gastrointestinal stromal tumors (GIST)


The most frequent locations of soft tissue sarcoma on the body are:

  • The limbs (50%)
  • The abdomen, thorax and areas deep in the abdominal cavity (including the retroperitoneum and the mediastinum): 45%
  • The head and neck: 5%
  • Bone and cartilage sarcoma
  • Bone tissue sarcoma may be:
  • osteosarcoma, which develops in most cases on the bones and limbs, in particular the femur (near the hip or knee) and the pelvis.
  • Ewing sarcoma, which can be located on all large bones, but especially the bones of the pelvis or legs.
  • Chondrosarcomas are tumors that develop from cartilaginous tissue.


Some 50% of sarcomas display specific molecular anomalies (generally caused by genetic alterations). For example, liposarcomas may be associated with amplification of the MDM2 and CD4K genes. In 1984, Olivier Delattre’s team at Institut Curie discovered the genetic anomaly associated with Ewing sarcoma: a merging of the EWS and FLI1 genes. In some cases, these anomalies may be targeted by new treatments.