Types of cancer

Soft tissues sarcomas

Soft tissue sarcomas can affect the entire human body, such as muscles, bones, blood vessels, tendons, cartilage and fat cells. They are rare and most have no known risk factor. Learn more.
5 min read
per: Grupo Oncoclínicas
Soft tissues sarcomas
Soft tissue sarcomas are rare and can affect the entire body, including muscles, bones, blood vessels, tendons, cartilage, and fat cells.

What are soft tissue sarcomas

Sarcomas are a heterogeneous group of tumors that encompass three major groups: soft tissue, bone and GIST (gastrointestinal stromal tumor).

Soft tissue sarcomas are rare tumors that originate in “soft tissues” such as muscle, bone, tendons, blood vessels, fat cells and cartilage – and therefore can affect any part of the body.

There are about 100 subtypes of sarcomas, but they are rare and account for less than 2% of all cancers in adulthood. In Brazil, there are few epidemiological studies on the disease, but the comparison of regional data with international databases shows that the incidence and prognosis of these tumors is similar in the country and in the rest of the world.

About 50% of soft tissue sarcomas originate in the arms and legs, 40% in the trunk and 10% in the head and neck. The digestive tract can also be affected, as well as the back of the abdomen (retroperitoneum) and the female reproductive system (gynecologic sarcomas).

Its causes are unknown in most patients, although a small percentage of cases are related to factors such as hereditary genetic syndromes (such as neurofibromatosis or von Recklinghausen disease, Gardner syndrome, Li-Fraumeni syndrome, retinoblastoma, Werner syndrome, Gorlin syndrome and tuberous sclerosis), weakening of the immune system due to HIV infection and exposure to radiation and chemicals.

Subtypes of soft tissue sarcomas

The most relevant subtypes among soft tissue sarcomas are:

  • Angiosarcoma – malignant tumor that can develop from the inner lining of blood vessels (anywhere in the body, but commonly the skin, breast, liver, spleen, deep tissues). These tumors are associated with radiation exposure and may start in areas that have undergone radiotherapy to cure other diseases, such as cancer itself;
  • Small round cell desmoplastic tumor – a rare sarcoma that occurs in adolescents and young adults. It is most often found in the abdomen;
  • Epithelioid sarcoma – most develop in tissues under the skin of the hands, forearms, feet, or legs. It is more frequent in adolescents and young adults;
  • Liposarcomas – malignant tumors of adipose tissue (fat cells), they can develop anywhere on the body, but are most common on the thighs, below the knees and inside the abdomen;
  • Rhabdomyosarcoma – originates from the cells that make up skeletal muscles. It is the most common type of soft tissue sarcoma seen in children;
  • Dermatofibrosarcoma protuberans – originates in deep layers of the skin, usually on the trunk or limbs. It grows in nearby tissues and rarely spreads to distant sites;
  • Desmoid fibromatosis – slow and steady growing tumor. Rarely spreads to distant locations, but has potential for local aggression;
  • Pleomorphic sarcoma: the most frequent subtype of sarcoma in adults. It originates mainly in the lower limbs;
  • Leiomyosarcoma: It starts in cells called smooth muscles, responsible for involuntary muscle contraction, which are found in organs and vessels. This means that they can originate anywhere in the body, with the stomach, limbs and uterus being the most common sites;
  • Gastrointestinal stromal tumor (GIST): is a tumor that originates from Cajal cells, a group of cells present in the wall of the organs of the gastrointestinal tract and responsible for intestinal motility (giving signals for the muscles to move liquids and food through the gastrointestinal tract) . This tumor can originate anywhere in the gastrointestinal tract, from the esophagus to the anus.

Symptoms of soft tissue sarcomas

Symptoms depend on the type of soft tissue sarcoma and the affected site. Usually, the first sign is a painless nodule. Tumors larger than 5 cm should be considered suspicious and evaluated by an experienced professional.

In general, soft tissue sarcomas are asymptomatic in their early stages. As the tumor develops, there is an increase in the volume of the affected area, as well as possible edema and changes in local sensitivity. Pain arises when the tumor grows and presses on the nerves – in these cases, there may be a manifestation of motor difficulty.

Tumors that start from the digestive tract can cause bleeding in the stool, vomiting and anemia, as well as abdominal pain.

Diagnosis of soft tissue sarcomas

The diagnosis of soft tissue sarcomas begins with a physical examination after observing some of the symptoms. Blood tests are done to help detect the disease, and imaging tests such as CT, MRI, and PET-CT are important to find the location of the tumor and assess both the extent of local disease and whether it has spread. to other parts of the body (so-called metastases).

After image analysis, the diagnosis is made by means of biopsy, which consists of removing a piece of the tumor and analyzing it in the laboratory to confirm the subtype, degree of aggressiveness and molecular characteristics that may help in the treatment.


The low incidence, its broad spectrum of subtypes, biological behaviors, and ubiquity make the management of soft tissue sarcomas challenging. Therefore, treatment should be carried out in a multidisciplinary environment, with teams of experienced specialists.

Treatment depends on the type, size and location of the tumor and may use the three most common modalities in oncology:

  • Surgery;
  • Radiotherapy;
  • Chemotherapy

For localized tumors – those that have not spread to other organs or tissues – surgery to remove the lesion is always recommended. Chemotherapy and radiation therapy can be used before (as neoadjuvants) or after (adjuvants) surgery, with the aim of increasing the chance of cure or decreasing the risk of recurrence (tumor coming back).

In locally advanced or metastatic sarcomas, the main treatment is systemic, based on chemotherapy or targeted therapies. The choice of medications depends on the type of tumor and the patient’s clinical conditions.

In some cases, radiation therapy and surgery may be used to control symptoms and metastases.

Treatment is a course that, in addition to drugs, surgery and radiotherapy, includes regular consultations with blood tests, imaging and clinical evaluation by the doctor. The frequency and duration of treatment are assessed individually.

Whenever possible, the option to participate in a clinical trial should be evaluated. Clinical trials are important because they try to find new cancer treatments and test their effectiveness and safety compared to existing treatments. Patients who are part of a clinical trial can receive standard treatment or be the first to use new therapeutic options, improving treatment and understanding of cancer.


Most soft tissue sarcomas have no known risk factor, which makes prevention difficult. There is no routine exam to help detect the disease.

For those who are carriers of hereditary genetic syndromes related to the disease, regular screening exams can help in the early diagnosis of these tumors and result in a greater chance of cure in the treatment.


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