Kidney Cancer Types

There are two main types of primary kidney cancer: renal cortical tumors and transitional cell (urothelial) tumors. These types are different in the way they develop and change over time, as well as in how they should be treated.

Renal Cortical Tumors
Up to 90 percent of kidney tumors are renal cortical tumors. These tumors start in the main part of your kidney, which contains structures called renal tubules.

Your kidneys each hold more than a million nephrons, which filter your blood and produce urine. Each nephron is associated with a renal tubule. Tubules join together to form collecting ducts. These ducts deposit the urine in your renal pelvis.

Cancer that develops in the renal tubules is called a renal cortical tumor. There are several types, and they don’t necessarily affect people in predictable ways. Some types are some are malignant (cancerous). But other types — such as renal cysts, oncocytomas, and angiomyolipomas — are benign (noncancerous).

Transitional Cell (Urothelial) Tumors
This type of kidney cancer starts in your renal pelvis, where the renal tubules leave urine. We’ll consider such factors as the location and size of a transitional cell tumor in deciding on the best approach for you.