Renal cell carcinoma (RCC) is a cancer that develops in the kidneys. Sarcomatoid RCC is a form of RCC that causes a person’s cancer to contain specific sarcomatoid cell types. It is an aggressive form of RCC, with a generally poor outlook.

Sarcomatoid RCC cells grow quickly, and the disease often spreads to other areas of the body. Once the cancer spreads, it can become harder to treat and worsen the person’s outlook.

This article outlines what sarcomatoid RCC is. It also explains its features, prevalence, symptoms, causes, and possible treatments.

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Sarcomatoid RCC is a highly aggressive form of RCC. RCC is a disease in which cancer cells develop in the tubules of the kidneys that filter and clean the blood. They remove waste products from the blood and make urine.

Most kidney cancer cells begin as clear cells. If a person has sarcomatoid RCC, the cancer cells appear differently and look similar to sarcoma cells.

Sarcoma is a broad term for a number of cancers. Sarcoma cancers begin in the connective tissues and soft tissues.

Sarcomatoid RCC cells tend to grow faster than other types of kidney cancer. These cells are also more likely to spread to other areas of the body. This means the cancer has advanced by the time a person receives a diagnosis, making it difficult for medical professionals to treat.

What do the cells look like under a microscope?

Standard RCC cells have epithelial features. This means they are either:

  • squamous, which are flat and sheet-like in appearance
  • columnar, which are column-like in appearance
  • cuboidal, meaning they are cube-like in appearance

The characterization of sarcomatoid RCC includes the loss of these characteristic epithelial components.

Histologically, sarcomatoid RCC also contains features such as:

  • Spindle cells: These are cells that appear long and slender when seen under a microscope.
  • High cellularity: This indicates the presence of a large number of clusters of cells.
  • Cellular atypia: This means the cells may appear abnormal.

A 2020 article states that medical professionals diagnose around 73,750 kidney cancers annually in the United States. These cancers contribute to an estimated 14,830 deaths per year.

Approximately 90% of all kidney cancers are RCCs.

Sarcomatoid features are present in approximately 4–5% of all RCCs.

The majority of people with sarcomatoid RCC have locally advanced or metastatic disease.

Locally advanced cancer is cancer that has grown outside the part of the body where it started. However, locally advanced cancers have not yet spread to other, distant parts of the body.

Metastatic cancers have spread from where they started to other parts of the body. This can make them difficult for medical professionals to cure or control with treatment.

Because most people with sarcomatoid RCC have locally advanced or metastatic RCC, approximately 90% show symptoms.

Symptoms of sarcomatoid RCC are similar to the standard RCC symptoms and include:

  • pain in the side or abdomen
  • blood in the urine
  • weight loss
  • fatigue
  • fever
  • night sweats
  • cough
  • difficulty breathing

The stage of a cancer describes how much it has grown and spread. A doctor will want to determine the stage of the cancer, so they can decide on treatments and assess a person’s outlook.

Below are the four stages of kidney cancer.

  • Stage 1: The tumor is 7 centimeters (cm) across or smaller. Stage 1 also means that the cancer is only in the kidney and has not spread to other areas of the body.
  • Stage 2: The tumor is larger than 7 cm across but is still only located in the kidney. The cancer has not yet spread to other areas of the body.
  • Stage 3: The cancer has spread to the lymph nodes near the kidney or the major veins or tissues around the kidney. Stage 3 also means the cancer has not yet spread beyond these areas. If a person has stage 3 sarcomatoid RCC, the tumor can be any size.
  • Stage 4: The tumor has grown into the adrenal gland, which sits on top of the kidney. Alternatively, the cancer has spread to the distant lymph nodes or other organs in other parts of the body.

The most common place for sarcomatoid RCC to spread is the lungs. It then spreads to the bones, lymph nodes, liver, and brain.

Scientists understand certain risk factors for RCC. However, they do not know what causes the disease to develop.

Certain risk factors that can increase a person’s chances of developing RCC include:

  • smoking
  • misusing certain pain medications, including over-the-counter pain medications
  • overweight
  • high blood pressure
  • a family history of RCC
  • certain genetic conditions, such as von Hippel-Lindau disease or hereditary papillary RCC

Treatment for sarcomatoid RCC is challenging. This is because the typical treatment options for RCC are not as effective in treating sarcomatoid RCC, according to a 2020 article. Treatment may include:


If a person has RCC without sarcomatoid features, they may undergo a nephrectomy. A nephrectomy is a surgical procedure where a surgeon removes the cancer and all or part of the kidney.

However, surgery is a less effective treatment if a person has sarcomatoid RCC. The 2020 study states that approximately 77–80% of people who have a nephrectomy to treat sarcomatoid RCC have a recurrence of the disease within 5–26 months.

Systemic treatments

Radiation therapy is not an effective treatment for sarcomatoid RCC. However, people with this condition can use radiation therapy as a palliative measure.

Palliative treatment aims to relieve pain and manage symptoms without treating the cause of the condition.

Radiation therapy can help a person with sarcomatoid RCC:

  • reduce pain
  • decrease neurological symptoms
  • reduce the amount of blood in their urine

Studies into chemotherapy, targeted therapy, and combination therapy to treat sarcomatoid RCC mostly show that these treatments are ineffective.

Immune checkpoint inhibitors

The immune system uses “checkpoints” to prevent it from attacking the body’s normal cells. These checkpoints are proteins that are present on immune cells. Cancer cells can sometimes use these checkpoints to prevent the immune system from attacking them.

Immune checkpoint inhibitors are drugs that target checkpoints on cancer cells. This can help a person’s own immune system attack the cancer cells.

Studies have shown that immune checkpoint inhibitors may be an effective treatment for sarcomatoid RCC.

This may be because sarcomatoid RCC tumors express certain checkpoint proteins at a much higher level than non-sarcomatoid RCC tumors.

Medical professionals require more research to determine whether immune checkpoint inhibitors are an effective treatment for sarcomatoid RCC.

Researchers of a 2020 review state that the outlook for a person with sarcomatoid RCC is generally poor. This is because 60–80% of people have advanced or late-stage disease at the time of diagnosis.

The average survival time is approximately 6–13 months.

The 2020 review reports that people with more than 25% of cancer cells with sarcomatoid features have an approximately 30% increased risk of dying of any cause.

People with more than 30% of cancer cells with sarcomatoid features have an approximately 52% increased risk of dying.

A doctor can diagnose kidney cancers in a number of ways. They will often perform a physical exam and ask questions about the person’s symptoms.

They may then carry out blood tests and urinalysis testing. A doctor may also use imaging tests to look for signs of a tumor.

Imaging tests can include:

If a doctor finds a suspicious mass that could be a tumor, they may take a biopsy to look for cancer cells.

The symptoms of sarcomatoid RCC are very similar to the symptoms of RCC. Imaging techniques are not able to outline sarcomatoid differentiation in kidney cancers. This can make it difficult to diagnose sarcomatoid RCC specifically.

Certain symptoms may indicate that a person has RCC. If a person experiences some of these symptoms, they may consider contacting a doctor to receive a diagnosis.

These include:

  • pain in their side
  • pain in their abdomen
  • blood in their urine

Other symptoms of RCC include weight loss, fatigue, fever, and night sweats.

Sarcomatoid RCC is an aggressive form of RCC.

Common symptoms include side pain, abdominal pain, blood in the urine, weight loss, fatigue, fever, and night sweats.

Sarcomatoid RCC often grows at a faster rate than RCC. It also often spreads to other areas of the body. This can make it difficult to treat.

A person with sarcomatoid RCC often has a poor outlook, and the average survival time is 6–13 months.

There are very few effective treatment options for sarcomatoid RCC. One potential treatment is immune checkpoint inhibitors, but more research is necessary to determine whether they are an effective option.