Merck Manuals, an online medical library, reports that kidney cancer accounts for more than 2 to 3 percent of all cancers in adults in the United States. Men are 50 percent more likely to have kidney cancer than women. Smoking is a major risk factor for this disease. Blood in the urine is the most common symptom of all types of kidney cancer, of which there are a few different types.
Renal Cell Cancer (RCC)
The National Cancer Institute notes that renal cell cancer (RCC) is the most common type of kidney cancer in adults. There are five subtypes of renal cell carcinoma, according to the UCLA health system, classified based on the appearance of the cells under the microscope. Clear cell RCC is the most common form of RCC, with more than 80 percent of people with RCC having this type; these cells appear very clear or pale under the microscope. Papillary RCC is the second most common RCC, affecting 10 to 15 percent of people with RCC; these cells form finger-like projections called papillae. Chromophobe RCC is the third most common type of RCC, accounting for about 5 percent of RCC cases; these cells are also rather clear, but are much larger than clear cell RCC. Collecting duct RCC is the most rare form, with the cells forming the shape of irregular tubes. Renal cell carcinoma may also be placed in the category of "unclassified RCC" because the appearance of the cells does not firmly place them into any one category.
Transitional Cell Carcinoma
The UCLA Health System reports that 5 to 10 percent of all kidney cancers are transitional cell carcinoma. The cells that become cancerous are a part of the renal pelvis, which is the junction between the kidney and the ureter (the tube that brings urine to the bladder). This type of cancer is highly treatable if caught early enough, with a success rate of 90 percent.
Wilms' tumor
The National Cancer Institute reports that this type of kidney cancer is the most common type of childhood kidney cancer. Even though only approximately 5 to 6 percent of all kidney cancers are Wilms' tumors, almost all cases of this form of cancer are found in children around 3 or 4 years of age; only extremely rarely does it occur in adults. According to the Mayo Clinic, scientists think this type of cancer develops from immature developing kidney cells.
