Malignant Soft Tissue Tumors


What are malignant soft tissue tumors?

Malignant soft tissue tumors are rare tumors that account for only 1% of all cancers. These tumors, also known as sarcomas, are cancerous tumors that appear in soft connective tissues. Soft connective tissues, along with bones, form and support your body’s connecting structures. Soft tissues include:

  • Muscles.
  • Ligaments.
  • Tendons.
  • Cartilage.
  • Fat.
  • Blood vessels.
  • Lymph vessels.

Where do malignant soft tissue tumors appear?

Malignant soft tissue tumors can appear in any part of your body, but 60% begin in arms and legs. Approximately 30% begin in the torso or abdomen, and 10% appear in the head and neck.

Who gets malignant soft tissue tumors?

Malignant soft tissue tumors can happen at almost any age, but are most common in individuals between 50 and 70 years of age.

There are around 50 different types of these tumors. Typically, these tumors are classified based on where the tumor started. Some of the most common types that affect adults include:

Symptoms and Causes

What are the symptoms of malignant soft tissue tumors?

Tumors that start in your arms and legs might appear to be painless lumps that grow over time. These tumors can grow to be quite large before becoming painful.

The first symptoms of tumors that start in your stomach (abdomen) might come from problems the tumor causes, such as blocking your stomach or bowels.

When should you contact your healthcare provider with symptoms of malignant soft tissue tumors?

If you notice these symptoms, contact your healthcare provider:

  • A new lump or a fast-growing lump anywhere on your body.
  • A lump that’s grown 5 centimeters (cm) or larger, or about the size of a golf ball.
  • A lump that’s become painful.
  • Worsening abdominal pain.
  • Blood in your poop or vomit, or if your poop appears black or like tar. (This could be a sign there’s bleeding in your stomach or bowels.)

Diagnosis and Tests

How are malignant soft tissue tumors diagnosed?

Diagnosing malignant soft tissue tumors takes several steps.

Healthcare providers typically begin with a thorough medical history and physical examination. They might also complete certain tests. Test results help doctors determine more information about the tumor.

This process is called staging and helps your healthcare provider correctly diagnose and treat the tumor.

What kinds of tests are done to diagnose malignant soft tissue tumors?

These tests might include:

  • X-ray: An X-ray looks for abnormal growths.
  • Computed tomography (CT): CT uses computers to combine many X-ray images into cross-sectional views of the inside of your body. This test is often used to diagnose tumors in your chest, abdomen or back of your abdomen.
  • Magnetic resonance imaging (MRI): MRI uses a large magnet, radio waves and a computer to create clear images of your body. This may be ordered for clearer pictures if an X-ray isn’t normal.
  • PET scan: This test uses a special glucose tracer that’s concentrated in cancer cells, and shows the areas in your body where the glucose is higher than normal, suggesting the presence of a rapidly growing tumor.
  • Ultrasound: This test relies on sound waves and their echoes to develop pictures of parts of your body.
  • Biopsy: This is a procedure in which a piece of tissue from the affected area is removed so it can be studied for cancer cells under a microscope.

What’s involved in the staging process?

Staging — the process of finding out whether or not and/or how far cancer from a tumor might have spread — is the final step in diagnosing these tumors. Staging also helps doctors plan treatments.

Doctors determine the spread of cancer by assigning a stage between I and IV. The higher the number, the more the cancer has spread (metastasized).

There are different ways to stage tumors based on a tumor’s location. To stage a tumor, your healthcare provider might consider the following factors:

  • The tumor’s size.
  • The tumor’s original location.
  • Whether the tumor has spread, and where it has spread.
  • The tumor’s grade, or how the tumor’s cells appear when viewed under a microscope. A tumor’s grade is how healthcare providers determine how quickly a tumor might grow or spread. For example, a low-grade tumor is likely to grow and spread less quickly than higher-grade tumors.

What are the stages of malignant soft tissue tumors?

These tumor stages include:

  • Stage I: Stage I is divided into stages IA (smaller than 5 cm or 2 inches) and IB (larger than 5 cm).
  • Stage II: Stage II is divided into stages IIA (smaller than 5 cm) and IIB (larger than 5 cmrs) for soft tissue tumors of the head and neck, extremities (arms and legs), gastrointestinal tract and retroperitoneum (the part of your body behind your abdomen).
  • Stage III: Stage III is divided into IIIA or IIIB based on the size of the tumor, lymph node involvement or grade (based on the type of tumor).
  • Stage IV: The tumor has spread to lymph nodes in arms and legs or other parts of your body.

Management and Treatment

What are my treatment options for malignant soft tissue tumors?

Treatment options depend on what healthcare providers learn about the tumor while diagnosing it, including the tumor type, location and stage. Treatment options range from medical treatments such as chemotherapy, radiation or targeted drug therapy, to surgical treatments. In many cases, medical treatments are used in addition to surgery.

Medical treatments

  • Chemotherapy: People who receive this treatment are given drugs, by either mouth or IV. Chemotherapy might be used as a primary treatment before surgery to shrink tumors that’ll be removed during surgery, or after surgery, to eliminate any cancer cells that remain.
  • Radiation: Radiation might be used before surgery to shrink tumors, or after surgery, to eliminate any remaining cancer cells.
  • Targeted therapy: This treatment is aimed at specific parts of cancer cells (such as genes and proteins) to change how they survive and grow.

Surgical treatments

Surgery is a common treatment for malignant soft tissue tumors and is done to minimize the risk that a tumor will return or spread. Surgeons want to remove the tumor without leaving any cancer cells behind while leaving as much healthy tissue in place as possible.

Outlook / Prognosis

What is the outlook for people with malignant soft tissue tumors?

As with treatment, healthcare providers use several factors to determine your prognosis, or expected outcome.

These factors include the size and spread of the tumor when the cancer was diagnosed and how treatments affected the tumor. Approximately 60% of malignant soft tissue tumors are found to be limited to one area of the body at the time of diagnosis. Another 19% of tumors have spread to nearby tissues and organs at the time of diagnosis, and 15% of tumors have spread to distant parts of the body.

Like with many cancers, early diagnosis of malignant soft tissue tumors means a better prognosis.

A note from Cleveland Clinic

A malignant soft tissue tumor diagnosis can be frightening, but it’s important to remember that there are many people who are there to help you. Your healthcare providers will work to provide the best possible treatment plan based on your individual case and needs. Don’t hesitate to ask about support groups, too — your healthcare team is eager to provide you with the best resources available.

Last reviewed by a Cleveland Clinic medical professional on 03/28/2022.


  • American Cancer Society. Soft Tissue Sarcoma: Early Detection, Diagnosis, and Staging. ( Accessed 3/28/2022.
  • American Society of Clinical Oncology. Sarcomas, Soft Tissue, Introduction. ( Accessed 3/28/2022.
  • National Cancer Institute/National Institute of Health. Adult Soft Tissue Sarcoma Treatment. ( Accessed 3/28/2022.

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