Soft Tissue Sarcoma: What You Should Know About a New or Growing Lump

Discovering a lump can be unsettling. It is natural to wonder what it is and whether you should be concerned.

The reassuring truth is that most soft tissue lumps are not cancerous. Many are harmless growths, such as lipomas or cysts. However, a lump that is growing, feels deep or does not go away should be properly assessed.

Dr Thomas Hilton, an orthopaedic oncologist in Cape Town, explains what soft tissue sarcoma are, which symptoms deserve attention and why specialist assessment is important before a suspicious lump is biopsied or removed.

What is a soft tissue sarcoma?

A soft tissue sarcoma is a rare type of cancer that begins in the tissues that connect, support and surround other parts of the body. These include:

Soft tissue sarcomas can develop almost anywhere in the body. They are commonly found in the arms, legs, abdomen or trunk.

There are many different types of soft tissue sarcoma, and each can behave differently. Identifying the exact subtype is an important part of reaching an accurate diagnosis and planning the most appropriate treatment.

What are the symptoms of soft tissue sarcoma?

The most common sign of a soft tissue sarcoma is a new or growing lump. In its early stages, the lump may not be painful. This can make it easy to overlook or mistake for a minor injury or harmless fatty lump.

As the tumour becomes larger, it may press against nearby muscles, nerves or other structures. This can cause pain, discomfort, weakness or difficulty moving the affected area.

A soft tissue lump should be assessed if it:

Having one or more of these symptoms does not mean that you have a soft tissue sarcoma. It does, however, mean that the lump deserves further assessment.

Most soft tissue lumps are not cancerous

Benign soft tissue tumours are much more common than sarcomas. Lipomas, cysts and other non-cancerous conditions can all cause lumps beneath the skin.

Unfortunately, it is not always possible to identify a lump simply by looking at or feeling it. A painless lump is not automatically harmless, particularly if it is growing or located deep within the tissue.

Seeking an assessment does not mean assuming the worst. It is a sensible step towards understanding what the lump is and whether further investigation is needed.

How is a soft tissue tumour diagnosed?

The process usually begins with a consultation and physical examination. Your doctor will ask when you first noticed the lump, whether it has changed and whether it is causing pain or affecting movement.

The next step may involve diagnostic imaging.

Why should a biopsy be carefully planned?

A biopsy is usually needed to confirm whether a suspicious soft tissue tumour is cancerous and to determine its exact type.

However, the position and method of the biopsy matter. The biopsy pathway may need to be removed during later surgery, so it should be planned with any potential definitive treatment in mind.

For this reason, it is generally best for a suspicious soft tissue mass to be assessed by an orthopaedic oncologist or soft tissue tumour specialist before it is biopsied or removed.

Removing an unexplained lump without suitable imaging and biopsy planning can make further surgery more complicated if it is later found to be a sarcoma.

What happens after a soft tissue sarcoma diagnosis?

If the biopsy confirms a soft tissue sarcoma, the medical team will assess its grade and stage.

The grade describes how the tumour cells look under a microscope and provides information about how the tumour may behave.

The stage considers factors such as:

• The tumour’s size

• Where it is located

• Whether it involves surrounding structures

• Whether it has spread elsewhere in the body

These findings help the team plan treatment according to the individual tumour. Soft tissue sarcoma treatment is not the same for every patient.

How is soft tissue sarcoma treated?

Treatment depends on the type, size, grade and location of the sarcoma, as well as the patient’s overall health.

Because sarcomas are rare, treatment is best planned by a multidisciplinary team. This may include an orthopaedic oncologist or tumour surgeon, radiologist, pathologist, medical oncologist, radiation oncologist and rehabilitation team.

Surgery

Surgery is often the main treatment for a localised soft tissue sarcoma. The goal is to remove the tumour completely, together with a margin of healthy tissue, while preserving as much movement and function as possible.

The operation required will depend on the tumour’s location and its relationship to nearby muscles, nerves, joints and blood vessels.

Radiotherapy

Radiotherapy may be recommended before or after surgery. It may help reduce the risk of the sarcoma returning in the same area.

Whether radiotherapy is appropriate depends on factors such as the tumour’s grade, size, location and surgical margins.

Chemotherapy and other treatments

Chemotherapy may be helpful for certain soft tissue sarcoma subtypes or stages, but it is not required for every patient.

Targeted therapies or immunotherapy may also be considered in selected cases. These decisions are made according to the specific tumour and the individual patient’s circumstances.

Preserving movement and quality of life

Soft tissue sarcoma treatment is not only about removing the tumour. Sarcomas may develop close to structures that are important for movement and daily function.

Careful surgical planning considers both cancer control and the patient’s life after treatment. Where it is medically appropriate, the aim is to preserve the limb and maintain as much strength, mobility and independence as possible.

Physiotherapy and rehabilitation may form an important part of recovery, helping patients regain movement, rebuild strength and return to their usual activities.

Follow-up after soft tissue sarcoma treatment

Regular follow-up remains important after treatment. Appointments may include a clinical examination and repeat imaging to monitor the area where the tumour was removed and check for any signs of recurrence.

Chest imaging may also be recommended because the lungs are one of the areas to which certain soft tissue sarcomas can spread.

The timing of follow-up appointments depends on the sarcoma subtype, grade, treatment received and individual risk of recurrence.

It is normal to feel anxious before follow-up visits. Patients should feel comfortable discussing new symptoms, changes around the surgical area or concerns about their recovery with their medical team.

When should you see a soft tissue tumour specialist?

If you are concerned about a new or growing soft tissue lump, Dr Thomas Hilton can help you get the clarity you need. Early, specialist assessment makes it possible to plan the right imaging and biopsy pathway from the start - and, in most cases, offers real reassurance.

Book a consultation with Dr Thomas Hilton in Cape Town to have a soft tissue lump properly assessed.