Kidney Cancer Information
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What is Kidney Cancer?
Kidney cancer is the development of malignant cells in the tissues of the kidneys. The kidneys are a pair of organs in the abdomen that remove waste from the blood.
As kidney cancer grows, it may invade organs near the kidney, such as the liver, colon or pancreas. Kidney cancer cells may also break away from the original tumor and spread (metastasize) to other parts of the body. When kidney cancer spreads, cancer cells may appear in the lymph nodes. For this reason, lymph nodes near the kidney may be removed during surgery.
If a pathologist finds cancer cells in your lymph nodes, it may mean that the disease has spread to other parts of the body. Kidney cancer may spread and form new tumors, most often in the bones or lungs. The new tumors have the same kind of abnormal cells and the same name as the original (primary) tumor in the kidney. For example, if kidney cancer spreads to the lungs, the cancer cells in the lungs are kidney cancer cells. The disease is metastatic kidney cancer; it is not lung cancer.
Each year, more than 28,000 people in the United States learn that they have kidney cancer. Kidney cancer is most prevalent in individuals between the ages of 55 and 84.
Types of Kidney Cancer
Renal cell carcinoma (RCC) is the most common type of kidney cancer. The cancerous cells typically accumulate into a single small mass or tumor within the kidney's tubules. Over time, this mass may grow and cause an obstruction. The cancer may form in one or both of the kidneys.
Subtypes of Renal Cell Carcinoma
- Clear Cell RCC accounts for approximately 80 percent of all renal cell carcinomas. The epithelial tumor cells will appear very pale or transparent (clear) when observed under a microscope.
- Papillary RCC show a very distinct growth pattern, where the cancer develops finger-like projections or protuberances throughout the tumor. However, some clear cell RCCs may also develop similar patterns but may not necessarily be diagnosed as papillary RCC because of some other technical criteria. Approximately 10-15 percent of kidney cancers are diagnosed as papillary RCC, which may also be called chromophilic in reference to a type of diagnostic technique that uses dye.
- Chromophobe RCC, like clear cell RCC, has tumor cells that are characterized by transparent cytoplasm so that they appear pale or clear under a microscope. However, these cells tend to be larger in size.
- Collecting Duct RCC is a very rare variant of RCC, accounting for less than 1 percent of kidney cancers.
- Unclassified RCC is a rare variant that cannot easily be classified. Cancers that have more than subtype may be grouped in this category.
Other Cancerous Kidney Tumors
- Transitional cell carcinoma may also be referred to as urothelial cancer or renal pelvis carcinoma. The cancer develops in the region where the kidney and the ureter join. The tumor cells may begin to look more like bladder cancer cells than cells from kidney cancer when observed under a microscope.
- Renal sarcoma is a rare form of kidney cancer that develops in the connective tissue of the kidney.
Next Topic: Kidney Cancer Risk Factors
