Kidney Cancer Health Center
Tumors in the kidney can be benign (not cancer) or malignant (cancer). Benign tumors are not as harmful as malignant tumors.
Malignant or cancerous tumors, though, can invade nearby tissue and spread to the lymph nodes and other areas of the body.
They can also spread through blood vessels to the lungs, bones or liver. After spreading, kidney cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues. When cancer spreads, this is known as metastasis.
Types of kidney cancer
There are four types of kidney cancer:
- Renal cell carcinoma. The most common type of kidney cancer, renal cell carcinoma is seen in about 85 percent of cases. It starts in the kidney's filtering systems.
- Transitional cell carcinoma. This type begins in the area where urine collects before it travels to the bladder. Transitional cell carcinoma is also called urothelial carcinoma. This is very similar to and is treated like bladder cancer.
- Sarcoma. This rare form of kidney cancer can grow quite large, but sarcoma of the kidney does not usually metastasize as often as other types of kidney cancer.
- Wilms tumor. This is the most common form of kidney cancer in children. Wilms tumor is treated differently than adult kidney cancer.
Along with different types of kidney cancer, tumors are made up of different types of cells. There are about 10 different types of kidney tumor cells which are identified to help plan the best treatment.