Kidney cancers are classified based on the type of cell where they start and how the cancer cells look under a microscope. Knowing the type of kidney cancer can help your healthcare team predict how the cancer may behave and which kidney cancer treatments may work best.

When most people talk about kidney cancer, they’re referring to renal cell carcinoma (RCC) — the most common type. But RCC includes several subtypes, and there are also other, less common cancers that can develop in the kidneys. Moreover, some people develop kidney tumors that are benign (noncancerous), which still require monitoring and possibly treatment.

In this article, we’ll walk through the most common RCC subtypes as well as other kidney cancers. Understanding the specifics of your diagnosis can help you feel more prepared and have better conversations with your doctor about your treatment options.

1. Renal Cell Carcinoma

Renal cell carcinoma is the most common type of kidney cancer, accounting for 80 percent to 85 percent of all kidney cancer cases. RCC begins in the cells that line the renal tubules — tiny, hollow structures in the kidney that help filter the blood, return useful substances to the body, and remove waste as urine. These tubules are located in both the renal cortex (outer layer) and medulla (inner layer) of the kidney.

There are more than a dozen subtypes of RCC. A pathologist (a doctor who specializes in diagnosing health conditions by examining tissues) determines the specific subtype by studying the cancer’s appearance. This process is part of a field called tumor histology.

There are two main subtypes of RCC: clear cell RCC and non-clear cell RCC.

Clear Cell Renal Cell Carcinoma

Clear cell RCC makes up about 70 percent of RCC cases. Under a microscope, the cancer cells look pale or “clear,” which is where the name comes from. Most people with clear cell RCC don’t notice symptoms, especially in early stages. Compared to other subtypes, this form often grows faster and is more likely to metastasize (spread) to other parts of the body.

Treatment for early-stage clear cell RCC typically involves surgery, such as:

• Partial nephrectomy — Removal of the part of the kidney that contains the tumor, preserving as much healthy kidney tissue as possible
• Radical nephrectomy — Removal of the entire kidney, often along with nearby tissue or lymph nodes (small, bean-shaped structures that help the body fight infection and disease)

Other treatment options include:

• Radiation therapy — Uses high-energy rays to kill cancer cells or shrink tumors
• Immunotherapy — Helps the immune system recognize and attack cancer cells
• Targeted therapy — Uses drugs to block specific proteins or genes that help cancer cells grow and survive

Non-Clear Cell Renal Cell Carcinoma

Subtypes of RCC that aren’t classified as clear cell RCC are known as non-clear cell RCC. Papillary RCC and chromophobe RCC are the most common subtypes of non-clear cell RCC, but this group also includes several rare subtypes.

These rarer forms include:

• Collecting duct RCC — This type of RCC develops in the tubes that collect urine from the renal tubules and carry it to the bladder. It accountings for about 1 percent of all RCC cases
• Renal medullary carcinoma (RMC) — This is an aggressive RCC subtype, and it’s more common in young people of African descent with sickle cell disease or sickle trait, according to guidelines from the National Comprehensive Cancer Network.
• Multilocular cystic RCC — This type of RCC looks like clear cell RCC, but it tends to grow slowly.
• Translocation RCC — This subtype is more commonly diagnosed in children and young adults and is linked to specific changes in translocations (chromosomes).
• Clear cell papillary RCC — This subtype has features of both clear cell and papillary RCC.
• Unclassified RCC — This is a catch-all category for tumors that don’t match other known subtypes or show features of more than one type.

Specific symptoms and treatments may differ based on the subtype.

2. Papillary Renal Cell Carcinoma

Papillary RCC is the second most common subtype of RCC. About 10 percent to 15 percent of people with RCC have this type. Papillary RCC is named for its fingerlike projections (known as papillae) that can be seen under the microscope.

There are two main types of papillary RCC:

• Type 1 papillary RCC — Tends to grow more slowly, is generally considered less aggressive, and may involve multiple tumors in one or both kidneys
• Type 2 papillary RCC — Typically grows more quickly and is more likely to metastasize to other parts of the body

In general, papillary RCC causes symptoms similar to clear cell RCC, such as blood in the urine, side or back pain, or a lump in the kidney area. Treatments for papillary RCC often include surgery, immunotherapy, and targeted therapy, depending on the stage and specific characteristics of the tumor.

3. Chromophobe Renal Cell Carcinoma

About 5 percent to 10 percent of people diagnosed with RCC have chromophobe RCC. Under a microscope, chromophobe RCC cancer cells are larger and darker than the pale, clear cells seen in clear cell RCC.

Chromophobe RCC tends to be diagnosed at an earlier stage and may be more common in younger people. Additionally, in females, it’s more common than other types of kidney cancer, according to Critical Reviews in Oncology/Hematology. In general, kidney cancer is typically more common in men than women, according to the American Cancer Society.

Chromophobe RCC is often associated with a good prognosis (outlook) because it’s usually less aggressive than clear cell RCC. However, this type of RCC may not respond to some kidney cancer treatments, such as immunotherapy.

4. Transitional Cell Carcinoma

Transitional cell carcinoma (TCC) is a non-clear cell type of kidney cancer, and it’s the second most common type after RCC. This type accounts for about 8 percent of all kidney cancers.

Also known as urothelial carcinoma, TCC develops when transitional cells (the cells that line parts of the kidney and urinary tract) begin to grow out of control. In the kidney, these cells are found in the renal pelvis, the area where the kidney connects to the ureter (the tube that carries urine to the bladder). Because of where it starts, TCC of the kidney often resembles bladder cancer more than other kidney cancers.

People who have had bladder cancer or who have other kidney cancer risk factors — such as smoking or exposure to certain chemicals — may be at a higher risk of developing TCC. Symptoms of TCC are often similar to those of other kidney cancers and may include:

• Blood in the urine
• Side or back pain
• Frequent urination

Treatment options for transitional cell carcinoma may include:

• Nephroureterectomy — Surgery to remove the kidney, ureter, and a small portion of the bladder where the ureter connects
• Segmental ureterectomy — Removal of the cancerous section of the ureter, with the goal of preserving kidney function when possible
• Fulguration — A procedure that uses an electric current to destroy cancerous tissue
• Laser surgery — Use of a laser beam to remove cancer or kill cancer cells
• Chemotherapy — Drugs that kill fast-growing cancer cells or stop them from dividing; may be given before or after surgery
• Immunotherapy — Treatments that help the immune system recognize and attack cancer cells
• Targeted therapy — Medications that block specific proteins cancer cells use to grow and spread

5. Renal Sarcoma

Renal sarcomas are a rare type of kidney tumor, making up less than 1 percent of all kidney cancers. Sarcomas are cancers that begin in connective tissues, such as muscles, blood vessels, nerves, or fatty tissue. When this kind of cancer starts in the kidney’s connective tissue, it’s called a renal sarcoma.

In some cases, other kidney cancers, including RCC, can develop sarcomatoid features. This means the cancer cells don’t originate in connective tissue, but under a microscope they resemble sarcomas. Cancers with sarcomatoid features tend to be more aggressive, grow quickly, and are more likely to spread to other parts of the body.

Treatment for renal sarcoma often involves a combination of surgery, chemotherapy, and radiation. Even after treatment, renal sarcomas have a high risk of recurrence (returning), which makes follow-up care and monitoring especially important.

6. Wilms Tumor

Wilms tumor, also known as nephroblastoma, is a rare kidney cancer. While uncommon in adults, it is the most common type of kidney cancer in children.

Wilms tumors can form when the kidney cells in a developing baby don’t mature as they should. If these immature cells remain in the kidney after birth and continue growing without developing correctly, they can form a tumor — often around age 3 or 4.

Treatment for this type of kidney cancer often involves a combination of surgery, chemotherapy, and radiation. Children with Wilms tumor often respond well to treatment, especially when diagnosed early.

What To Know About Benign Kidney Tumors

Not all kidney tumors are cancerous. Benign kidney tumors can grow in the kidney and cause complications by taking up space or pressing on nearby structures.

Examples of benign kidney tumors include:

• Angiomyolipomas — These tumors are made of connective tissues (blood vessels, muscle, and fat). They are most commonly found in women, according to the American Cancer Society.
• Oncocytomas — These slow-growing kidney tumors can become large, but they don’t spread beyond the kidney.

Treatment for benign kidney tumors usually involves removing or destroying the kidney tumor with surgery or radiofrequency ablation. In some cases, active surveillance (regular monitoring with imaging tests) may be recommended if the tumor isn’t causing problems.

Find Your Team

On MyKidneyCancerTeam, the social network for people living with kidney cancer and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with kidney cancer.

What type of kidney cancer were you diagnosed with? Did your doctor discuss the type of kidney cancer and how that informs your treatment options? Share your experience in the comments below, or start a conversation by posting on your Activities page.