Symptoms, Diagnosis, Treatment & Prognosis
Soft tissue sarcoma is a rare type of cancer that develops in the body’s soft tissues, such as muscles, fat, tendons, fibrous tissue, blood vessels, or nerves. Although most soft tissue lumps are not cancer, some require prompt evaluation because early diagnosis and treatment by a specialist sarcoma team significantly improve outcomes. Treatment usually involves surgery and may also include radiotherapy (radiation treatment), chemotherapy (anti-cancer medicines), or other therapies depending on the type and stage of the tumor.
Finding a lump does not mean you have cancer. In fact, the vast majority of soft tissue lumps are benign conditions such as lipomas (fatty lumps) or cysts. However, because it is not always possible to distinguish a benign lump from a sarcoma by examination alone, persistent or suspicious lumps should be evaluated promptly. Early assessment provides the best opportunity for an accurate diagnosis and effective treatment.
Soft tissue sarcoma is a rare cancer that develops from the body’s soft tissues.
Soft tissues are the supporting structures that connect, surround, or protect other parts of the body. They include:
A sarcoma is a cancer that arises from these connective or supporting tissues. This differs from a carcinoma, which develops from organs or the lining of organs such as the breast, lung, colon, or prostate.
Although soft tissue sarcomas can occur almost anywhere in the body, they are most commonly found in the:
Because these tumors often grow slowly and painlessly at first, many patients mistake them for harmless lumps and may ignore them for several months.
Figure 1. Soft tissue sarcoma of the ankle, illustrating the tumor and the surgical specimen following wide excision.
A soft tissue sarcoma does not originate from the skin or the bones. Instead, it develops from the tissues beneath the skin that provide structure and movement to the body. Since these tissues are present almost everywhere, a soft tissue sarcoma can arise in nearly any part of the body.
A sarcoma is a malignant (cancerous) tumor arising from connective tissues.
Unlike more common cancers, sarcomas are relatively uncommon and often require management by a specialized multidisciplinary sarcoma team (MDT). An MDT is a group of healthcare professionals—including orthopaedic oncologists, surgical oncologists, radiologists, pathologists, medical oncologists, radiation oncologists, plastic surgeons, and rehabilitation specialists—who work together to determine the best treatment plan.
Different sarcoma subtypes behave differently. Some grow slowly over many years, while others grow rapidly and may spread (metastasize) if not treated.
Many people are familiar with cancers such as breast, lung, or colon cancer. These are carcinomas, which arise from epithelial cells—the cells that line organs and body surfaces.
Soft tissue sarcomas are different.
| Carcinoma | Soft Tissue Sarcoma |
|---|---|
| Begins in organs or skin | Begins in connective tissues |
| Very common | Rare |
| Managed by organ-specific cancer specialists | Managed by sarcoma specialists |
| Examples: Breast, lung, colon cancer | Examples: Liposarcoma, Leiomyosarcoma, Synovial Sarcoma |
Table. Differences between carcinomas and soft tissue sarcomas.
Although soft tissue sarcomas are rare, they include more than 70 distinct subtypes, each with unique biological behavior, treatment approaches, and prognosis. This is one reason why specialist evaluation is so important.
Soft tissue sarcomas are uncommon, accounting for less than 1% of all adult cancers. They can occur at any age but are more frequently diagnosed in adults between 40 and 70 years of age.
Some types are more common in children and adolescents, while others occur almost exclusively in adults.
Because these tumors are rare, many general practitioners and surgeons encounter only a few cases during their careers. Referral to a specialized sarcoma center has been shown to improve diagnostic accuracy and treatment outcomes.
Rarity should never delay referral. A painless, enlarging soft tissue lump may be a benign condition, but it may also represent a sarcoma. When imaging or clinical findings raise suspicion, referral to a specialist sarcoma center before biopsy or surgery offers the best chance of optimal treatment.
Soft tissue sarcoma is not a single disease. Instead, it is a group of more than 70 different cancers that arise from different types of connective tissue. Each subtype has its own microscopic appearance, genetic characteristics, preferred location in the body, response to treatment, and long-term outlook.
For patients, the exact subtype identified on the pathology report is important because it helps guide treatment decisions and predict prognosis.
Fortunately, most patients do not need to memorize the names of all these subtypes. What matters most is understanding that your treatment plan is tailored to the specific type of sarcoma you have.
Some of the more frequently encountered adult soft tissue sarcomas include:
Children and adolescents can also develop soft tissue sarcomas, although the types differ from those seen in adults.
Examples include:
Pediatric sarcomas are managed by specialized pediatric oncology teams because treatment strategies and outcomes differ from adult disease.
Receiving a diagnosis of a rare sarcoma subtype can feel overwhelming. Remember that rarity does not mean it is untreatable. Modern pathology, advanced imaging, and multidisciplinary care allow treatment plans to be tailored to the specific characteristics of each tumor.
| Sarcoma Subtype | Tissue of Origin | Common Location |
|---|---|---|
| Liposarcoma | Fat | Thigh, abdomen |
| Leiomyosarcoma | Smooth muscle | Abdomen, blood vessels |
| Synovial Sarcoma | Soft tissues near joints | Knee, ankle, upper limb |
| Undifferentiated Pleomorphic Sarcoma | Connective tissue | Arms, legs |
| Myxofibrosarcoma | Fibrous tissue | Limbs |
| MPNST | Peripheral nerves | Limbs, trunk |
| Rhabdomyosarcoma | Skeletal muscle lineage | Children and adolescents |
The subtype influences several important aspects of care, including:
Your pathology report, imaging findings, and overall health are all considered together by the multidisciplinary team to create an individualized treatment plan.
One of the first questions many patients ask after diagnosis is, “Why did this happen to me?” In most cases, there is no single identifiable cause. Unlike some other cancers, soft tissue sarcomas are rarely linked to lifestyle choices, and most people diagnosed with a sarcoma have no known risk factors.
Researchers believe that soft tissue sarcomas develop when genetic changes (mutations) occur within the DNA of a normal cell. DNA contains the instructions that control how cells grow, divide, and repair themselves. When these instructions become abnormal, cells may continue to grow uncontrollably, eventually forming a tumor.
Importantly, these mutations usually occur by chance during a person’s lifetime and are not inherited from parents.
Most people with a soft tissue sarcoma have done nothing to cause their disease. Diet, exercise, stress, or minor injuries are not responsible in the vast majority of cases. Feeling guilty or searching for something you “should have done differently” is understandable but rarely reflects reality.
Approximately 90–95% of soft tissue sarcomas occur sporadically, meaning they develop without any identifiable cause.
Scientists believe that random DNA mutations accumulate over time within certain cells. Most of these mutations are harmless, but occasionally they affect genes that regulate cell growth, allowing a tumor to develop.
At present, there is no known way to prevent most soft tissue sarcomas.
A genetic syndrome is an inherited condition caused by changes in specific genes that increase the risk of developing certain diseases, including some cancers.
Although uncommon, a small proportion of soft tissue sarcomas occur in people with inherited cancer predisposition syndromes.
Examples include:
People with these conditions require lifelong medical surveillance because they are at increased risk of developing multiple types of cancer.
Fortunately, most patients with soft tissue sarcoma do not have one of these inherited disorders.
People who have previously received radiotherapy (radiation treatment) for another cancer have a small increased risk of developing a radiation-associated sarcoma many years later.
Radiation-associated sarcomas are uncommon and usually occur:
It is important to remember that the benefits of radiotherapy usually far outweigh this very small long-term risk, and radiation remains an essential part of treatment for many cancers.
Lymphedema is long-term swelling caused by impaired drainage of lymphatic fluid.
Rarely, longstanding lymphedema may lead to a highly aggressive sarcoma called lymphangiosarcoma (Stewart-Treves syndrome).
This complication is fortunately very uncommon.
Research has suggested associations between some chemicals and specific sarcoma subtypes, although these account for only a very small proportion of cases.
Examples include:
For most patients, no occupational exposure can be identified, and routine environmental exposures are not considered major causes.
Unlike cancers such as cervical cancer (caused by human papillomavirus, HPV) or liver cancer (associated with hepatitis viruses), most soft tissue sarcomas are not caused by viral infections.
One exception is Kaposi sarcoma, which is associated with Human Herpesvirus 8 (HHV-8) and occurs predominantly in people with weakened immune systems.
Kaposi sarcoma is biologically distinct from the soft tissue sarcomas discussed on this page.
Many misconceptions exist regarding the causes of sarcoma. Current scientific evidence does not support many commonly held beliefs.
Soft tissue sarcoma is not caused by:
Sometimes patients notice a lump after an injury. In these situations, the injury usually draws attention to a tumor that was already present, rather than causing it.
It is common to hear patients say, “I noticed the lump after I bumped my leg, so the injury must have caused it.” In reality, the injury often acts as a trigger for noticing a lump that had already been growing silently. Scientific studies have not shown that ordinary trauma causes soft tissue sarcoma.
| Risk Factor | Strength of Evidence | Common? |
|---|---|---|
| Random genetic mutations | Strong | Very common |
| Inherited genetic syndromes | Strong | Rare |
| Previous radiotherapy | Strong | Uncommon |
| Chronic lymphedema | Strong | Very rare |
| Certain chemical exposures | Moderate | Rare |
| Viral infection (Kaposi sarcoma only) | Strong | Rare |
| Minor trauma | No evidence | Not a cause |
| Exercise or physical activity | No evidence | Not a cause |
Researchers have identified specific genetic alterations in many sarcoma subtypes. Some of these changes not only help diagnose the tumor but may also guide the use of targeted therapies, a rapidly evolving area of sarcoma treatment.
The symptoms of a soft tissue sarcoma depend on its size, location, and the structures it affects.
One of the greatest challenges is that early soft tissue sarcomas often cause no symptoms at all. Many patients feel completely well and discover a lump accidentally while bathing, exercising, or changing clothes.
As the tumor enlarges, it may begin to press on nearby muscles, nerves, blood vessels, or bones, leading to additional symptoms.
The most common first symptom is a painless lump or swelling.
Typically, the lump:
Because painless lumps are usually benign, many patients initially assume they have a lipoma (fatty lump), delaying medical attention.
Contrary to popular belief, pain is not an early feature of most soft tissue sarcomas.
Pain may develop later if the tumor:
Therefore, the absence of pain should never reassure someone that a growing lump is harmless.
A painless, enlarging lump deserves the same attention as a painful one. Waiting for pain to develop before seeking medical advice may delay diagnosis.
A lump that is steadily increasing in size should always be evaluated.
Rapid enlargement may indicate:
Although rapid growth does not automatically mean cancer, it should never be ignored.
Soft tissue sarcomas may occur:
Deep tumors often become quite large before they are noticed because they remain hidden beneath normal muscle.
Depending on where the tumor develops, patients may experience:
These symptoms are caused by pressure effects rather than the cancer itself.
Tumors in the abdomen may become very large before causing symptoms because there is more space for them to grow.
Possible symptoms include:
Children often present differently from adults.
Parents may notice:
Any lump that persists beyond a few weeks or continues to enlarge should be assessed by a doctor.
If you notice a lump, taking a photograph with a ruler beside it every few weeks can help document whether it is increasing in size. However, photographs should never replace medical evaluation if the lump is growing or has concerning features.
Fortunately, most soft tissue lumps are benign. Common examples include lipomas, cysts, and benign fibrous tumors.
However, some features make a lump more likely to require specialist assessment.
One of the most useful clinical guidelines is the 5 cm rule.
A soft tissue lump larger than 5 cm (approximately the size of a golf ball) should be considered suspicious until proven otherwise.
Smaller sarcomas can occur, but larger size increases concern.
A lump should be evaluated promptly if it is:
These features do not necessarily mean cancer, but they warrant further assessment, usually with an MRI and, if indicated, a biopsy.
Most patients referred to a sarcoma clinic do not ultimately have a sarcoma. Referral is recommended because imaging and, when necessary, a biopsy are the only reliable ways to distinguish a benign lump from a malignant one. Seeking specialist evaluation early helps avoid delays, unnecessary surgery, and provides peace of mind regardless of the final diagnosis.
Diagnosing a soft tissue sarcoma involves more than simply identifying a lump. The goal is to determine whether the lump is benign (non-cancerous) or malignant (cancerous), identify the exact subtype of sarcoma, assess whether it has spread, and plan the safest treatment.
A diagnosis should ideally be made before any surgery is performed. Removing a lump without appropriate imaging and biopsy can complicate future treatment and may increase the risk of local recurrence.
Most patients undergo evaluation by a multidisciplinary sarcoma team (MDT), where specialists review the clinical findings, imaging studies, biopsy results, and treatment options together.
Diagnosing a soft tissue sarcoma is similar to solving a puzzle. No single test provides all the answers. Your symptoms, physical examination, MRI scans, biopsy findings, and pathology results are interpreted together before treatment decisions are made.
The diagnostic process begins with a detailed medical history and physical examination.
Your doctor may ask:
During the examination, the doctor assesses:
Although examination provides valuable clues, it cannot reliably distinguish a benign tumor from a sarcoma.
Magnetic Resonance Imaging (MRI) uses a powerful magnetic field and radio waves to produce highly detailed images of soft tissues. It is the preferred imaging test for evaluating most suspected soft tissue sarcomas.
MRI helps determine:
MRI also helps the surgeon plan the safest biopsy route and, later, the definitive operation.
Importantly, MRI should ideally be performed before a biopsy, as a biopsy can cause temporary bleeding and swelling that may alter imaging appearances.
MRI before biopsy is considered best practice for most suspected soft tissue sarcomas. It provides a clear roadmap for both diagnosis and surgery while minimizing the risk of an improperly placed biopsy tract.
Figure 2. MRI evaluation of a soft tissue sarcoma around the ankle, showing the tumor’s location and its relationship to surrounding tissues.
Ultrasound uses sound waves to examine soft tissues and is often the first imaging test ordered for a superficial lump.
Ultrasound can identify whether a lump is:
However, ultrasound has important limitations.
It cannot reliably distinguish all benign tumors from sarcomas and provides limited information about deep tissue involvement. If ultrasound raises concern or the lump has suspicious clinical features, an MRI is usually recommended.
Computed Tomography (CT) uses X-rays to create detailed cross-sectional images of the body.
Although MRI is preferred for evaluating the primary tumor, CT has several important roles:
Because the lungs are the most common site of metastasis (spread) for many soft tissue sarcomas, a CT scan of the chest is routinely performed before treatment.
A PET-CT scan combines CT imaging with a radioactive glucose tracer to identify areas of increased metabolic activity.
PET-CT is not required for every patient but may be useful in selected situations, such as:
Your specialist will decide whether PET-CT is appropriate based on the type and stage of your tumor.
A biopsy is a procedure in which a small sample of tissue is removed for microscopic examination.
It is the only reliable way to confirm the diagnosis of soft tissue sarcoma.
Although imaging can strongly suggest a sarcoma, treatment should not begin until the diagnosis has been confirmed by pathology, except in very rare circumstances.
The biopsy answers several important questions:
The preferred biopsy for most soft tissue sarcomas is a core needle biopsy.
Using local anaesthesia and image guidance (usually ultrasound or CT), a specially designed needle removes several small cylinders of tissue from the tumor.
Advantages include:
Occasionally, when a core needle biopsy is inconclusive or technically difficult, an incisional biopsy may be recommended.
During this procedure, a small incision is made to obtain a larger tissue sample.
The biopsy incision must be carefully planned because it is usually removed during the definitive tumor surgery.
A biopsy should never compromise future surgery. For this reason, the biopsy tract is deliberately placed so that it can be completely removed when the tumor is excised. This is one reason why biopsies are best performed by, or in consultation with, a specialist sarcoma team.
This is one of the most common concerns among patients.
Current scientific evidence shows that properly performed image-guided core needle biopsies do not increase the risk of cancer spreading throughout the body.
The biopsy tract is routinely removed during definitive surgery as an additional safety measure.
The benefits of obtaining an accurate diagnosis far outweigh the very small risks associated with biopsy.
It is natural to worry that a biopsy might “disturb” the tumor. Fortunately, modern image-guided biopsies are safe, highly accurate, and are considered an essential part of sarcoma care worldwide. An accurate diagnosis is the foundation of successful treatment.
The biopsy sample is examined by a pathologist—a doctor who specializes in diagnosing disease by studying tissues under the microscope.
The pathology report typically includes:
This information helps determine the most appropriate treatment.
Tumor grade describes how aggressive the cancer cells appear under the microscope.
It is not the same as tumor stage.
In general:
Grade helps predict the biological behavior of the tumor and influences decisions regarding chemotherapy, radiotherapy, and follow-up.
Tumor stage describes how far the cancer has spread within the body.
Staging considers several factors, including:
Staging investigations usually include:
| Tumor Grade | Tumor Stage |
|---|---|
| Describes how aggressive the cells appear under the microscope | Describes how far the cancer has spread |
| Determined by pathology | Determined by imaging and pathology |
| Low, intermediate, or high grade | Stage I–IV (depending on the staging system used) |
| Predicts biological behavior | Predicts disease extent and prognosis |
Soft tissue sarcoma is best managed by a multidisciplinary team, where specialists from different disciplines review each case together before treatment begins.
The MDT may include:
This collaborative approach ensures that treatment recommendations are individualized and based on the best available evidence.
Numerous studies have shown that patients treated at specialist sarcoma centres are more likely to receive an accurate diagnosis, appropriate surgery, and coordinated multidisciplinary care, leading to improved outcomes.
Treatment depends on several factors, including:
For most patients, treatment involves more than one specialty, even if only surgery is ultimately required.
The primary treatment options include:
The exact combination varies considerably from one patient to another.
Figure 3. Wide surgical resection of a soft tissue sarcoma around the ankle, resulting in a soft tissue defect after complete tumor removal.
Figure 4. Flap reconstruction after soft tissue sarcoma surgery, providing coverage of the surgical defect and helping preserve the function of the ankle.
Two patients with “soft tissue sarcoma” may receive completely different treatments because the subtype, grade, location, and stage of their tumors are different. Personalized treatment planning is one of the defining features of modern sarcoma care.
A diagnosis of soft tissue sarcoma does not automatically mean chemotherapy, radiotherapy, or amputation. Many patients are successfully treated with limb-sparing surgery, and treatment plans are carefully tailored to maximize cancer control while preserving function and quality of life.
For a detailed discussion of surgical techniques, radiotherapy, chemotherapy, reconstruction, rehabilitation, and follow-up care, please see: Soft Tissue Sarcoma Treatment.
Seeking a second opinion is a common and reasonable part of cancer care. It does not mean that you distrust your doctor. Instead, it provides an opportunity to confirm the diagnosis, review treatment options, and ensure that your care aligns with current evidence and international guidelines.
A second opinion may be particularly valuable if:
Ideally, the second opinion should be obtained before treatment begins, although it can still be helpful later in the treatment journey.
Specialist sarcoma centres review hundreds of cases every year. Their experience, combined with multidisciplinary discussion, can provide valuable insights for complex or uncommon tumors.
No. Most soft tissue lumps are benign conditions such as lipomas, cysts, or benign fibrous tumors. However, any lump that is enlarging, larger than 5 cm, deep, or persistent should be evaluated.
Yes, but many sarcomas are painless in the early stages. Pain usually develops when the tumor compresses nearby nerves, muscles, or other structures.
MRI is the best imaging test for evaluating most soft tissue masses, but it cannot confirm the diagnosis. A biopsy is required to determine the exact tumor type.
No. Modern image-guided core needle biopsies are safe and are considered the international standard for diagnosing soft tissue sarcoma.
Not necessarily. Chemotherapy is recommended only for selected sarcoma subtypes and stages. Many patients are treated with surgery alone or surgery combined with radiotherapy.
In most cases, no. Advances in limb salvage surgery allow preservation of the affected limb in the majority of patients.
Yes. Some sarcomas may recur locally or spread to other organs, which is why regular follow-up is essential.
Most soft tissue sarcomas are not inherited. Only a small proportion occur as part of inherited genetic syndromes.
Yes. Some sarcoma subtypes occur more commonly in children and adolescents and are managed by specialized pediatric oncology teams.
Consider asking:
The information provided on this page is intended for educational purposes only and should not replace professional medical advice, diagnosis, or treatment. Every patient and every sarcoma is unique. If you have a persistent soft tissue lump or have been diagnosed with a soft tissue sarcoma, consult an orthopaedic oncologist or specialist sarcoma multidisciplinary team for individualized evaluation and treatment.
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