Chromophobe renal cell carcinoma

by Trevor A. Flood, MD FRCPC
June 14, 2025

Chromophobe renal cell carcinoma is a type of kidney cancer. It develops from very small tubes (tubules) within the kidneys. It is the third most common type of kidney cancer in adults. Most people with chromophobe renal cell carcinoma have a very good prognosis. However, the outlook may change if special types of aggressive cells—called sarcomatoid or rhabdoid cells—are found in the tumour, or if the tumour is large or has spread.

What are the symptoms of chromophobe renal cell carcinoma?

Most people with chromophobe renal cell carcinoma do not have noticeable symptoms. Often, this tumour is discovered during imaging tests done for other health issues. When symptoms do occur, they can include:

• Blood in the urine (urine might look pink, red, or brown).

• Pain in the side or lower back.

• A lump or mass felt in the abdomen.

• Fatigue or unexpected weight loss.

Many of these symptoms are common to other conditions, so tests are needed for an accurate diagnosis.

What causes chromophobe renal cell carcinoma?

In most cases, the exact cause of chromophobe renal cell carcinoma isn’t known. Most cases occur by chance, and there is no clear reason why they develop. However, certain genetic (inherited) conditions can increase a person’s risk of developing this type of tumour.

What genetic syndromes increase the risk of chromophobe renal cell carcinoma?

The main genetic syndrome associated with chromophobe renal cell carcinoma is called Birt-Hogg-Dubé syndrome. This rare inherited condition increases a person’s risk of developing multiple kidney tumours, including chromophobe renal cell carcinoma. People with Birt-Hogg-Dubé syndrome may also have benign skin tumours and cysts in their lungs or liver. People with this syndrome often develop tumours at an earlier age than usual.

How is chromophobe renal cell carcinoma diagnosed?

Doctors often discover chromophobe renal cell carcinoma when performing abdominal imaging studies, such as ultrasound, CT scans, or MRIs, for other reasons. On these scans, chromophobe renal cell carcinoma appears as a mass or growth within the kidney.

Your doctor may then recommend a biopsy, a procedure that involves removing a small piece of the tumour for examination. In many cases, your doctor may suggest surgically removing the tumour first and examining it afterwards.

What does chromophobe renal cell carcinoma look like under the microscope?

When pathologists look at chromophobe renal cell carcinoma under the microscope, they see tumour cells that appear large, pale, or clear. These cells have a polygonal shape (meaning they have multiple sides) and form large sheets or groups. Tumours with these cells usually have an excellent prognosis, meaning they are less likely to spread and easier to treat successfully.

How do pathologists grade chromophobe renal cell carcinoma?

Pathologists classify chromophobe renal cell carcinoma into two grades—low grade and high grade—based on how much the tumour cells resemble normal kidney cells.

• Low-grade tumours: The tumour cells resemble normal kidney cells relatively closely and typically behave less aggressively.

• High-grade tumours: The tumour cells look more abnormal. High-grade tumours tend to grow faster and are more likely to spread.

Most chromophobe renal cell carcinomas are low grade. However, if sarcomatoid or rhabdoid cells (described below) are present, the tumour is considered more aggressive and higher grade.

What are sarcomatoid cells and why are they important?

Sarcomatoid cells are tumour cells that have changed in appearance and behavior, becoming more aggressive. Instead of polygonal-shaped cells, sarcomatoid cells appear as long, thin (spindle-shaped) cells. Tumours containing sarcomatoid cells are more likely to grow rapidly and metastasize to other parts of the body, resulting in a poorer prognosis.

What are rhabdoid cells and why are they important?

Rhabdoid cells are tumour cells that have changed to look like muscle cells. Tumours containing rhabdoid cells are also more aggressive and more likely to spread. Like sarcomatoid cells, the presence of rhabdoid cells indicates a worse outlook.

What is tumour necrosis?

Necrosis means that some of the tumour tissue has died. Tumour necrosis can occur when the tumour grows quickly and outgrows its blood supply. Finding necrosis usually indicates a more aggressive tumour and may mean a less favorable prognosis.

What is tumour extension?

Tumour extension refers to how far the tumour has grown beyond the kidney into surrounding tissues and structures. The kidneys are surrounded by a layer of fat and other nearby structures, including the adrenal glands, large veins, and surrounding connective tissues.

When examining the tumour, pathologists carefully check for tumour extension. If the tumour has grown into nearby tissues or organs, it usually indicates a higher tumour stage and potentially a less favorable outlook.

What is a surgical margin?

A margin is the border of normal, healthy tissue surrounding a tumour that surgeons remove along with the tumour during surgery. After removal, the pathologist checks these margins closely under a microscope to see if any tumour cells remain at the edges.

• A negative margin means no tumour cells are seen at the edges. This suggests the entire tumour was successfully removed, reducing the chance that the tumour will return.

• A positive margin means tumour cells are found at the edges. This suggests that some tumour cells might still be present in your body. Your doctor may recommend additional treatment or surgery if your margins are positive.

Margins depend on the type of surgery you have:

• Partial nephrectomy: Only part of the kidney is removed, so margins include the area where the kidney was cut and the surrounding fat.

• Radical nephrectomy: The entire kidney is removed, so the margins may include surrounding fat, the ureter (the tube leading to the bladder), and nearby large blood vessels.

Your pathology report will specify whether the margins are positive or negative and clearly identify their exact locations.

What is lymphovascular invasion?

Lymphovascular invasion means tumour cells have entered blood vessels or lymphatic vessels. Blood vessels carry blood, while lymphatic vessels carry fluid called lymph and connect to lymph nodes. Lymphovascular invasion increases the risk of tumour cells spreading to other areas, including lymph nodes or distant organs.

Were lymph nodes examined, and why is this important?

Lymph nodes are small, bean-shaped organs located throughout the body. They help the body fight infections and disease. Cancer cells from tumours can sometimes spread to lymph nodes through tiny channels called lymphatic vessels.

During surgery, doctors may remove nearby lymph nodes to check if cancer has spread. Pathologists carefully examine each lymph node under the microscope.

• Negative lymph nodes mean no tumour cells are present.

• Positive lymph nodes mean tumour cells are present. If positive, your report will describe the number of lymph nodes affected by cancer, their location, and the size of the largest tumour area found within them.

The presence or absence of cancer cells in lymph nodes helps determine the tumour’s stage and guides decisions about whether additional treatments, such as chemotherapy or immunotherapy, might be beneficial.

Pathologic stage of chromophobe renal cell carcinoma (TNM system)

Doctors use the TNM system to determine tumour stage, which helps plan treatment and predict prognosis:

Tumour stage (pT):

• T1: Tumour is 7 centimeters (cm) or smaller and remains entirely within the kidney.

• T2: Tumour is larger than 7 cm but still completely within the kidney.

• T3: Tumour has grown into the surrounding fat or a major vein attached to the kidney.

• T4: Tumour extends outside the kidney, through the kidney’s protective layer (Gerota’s fascia), or into nearby organs like the adrenal gland.

Nodal stage (pN):

• N0: No tumour cells in lymph nodes.

• N1: Tumour cells present in lymph nodes.

• NX: No lymph nodes were examined.

Metastatic stage (pM):

• M0: No spread to distant body parts.

• M1: Spread (metastasis) is found in distant body parts.

• MX: Cannot determine if distant spread has occurred (no distant tissue samples were examined).

Questions to ask your doctor

• Can you explain the stage and grade of my tumour clearly?

• Do I have sarcomatoid or rhabdoid features in my tumour?

• What are the best treatment options for my situation?

• What follow-up tests or monitoring will I need?

• What are the chances my tumour could return or spread?

• Are there lifestyle changes that can help manage my condition?

• Should my family members consider genetic testing?