There are five common types of benign, or non-canerous, kidney tumors, all of which are asymptomatic. In many cases, benign renal tumors are not life-threatening; however, they can still cause issues if they become too large.
The most common type of benign kidney tumor is renal adenoma. According to the American Cancer Society, these are small and slow-growing tumors. They are difficult to distinguish between renal cell carcinoma and are typically treated as if they were renal cell cancer.
Oncocytoma tumors grow rather large in size. Oncocytoma kidney tumors can sometimes be mistaken for renal adenomas, and are typically treated as such. Additionally, oncocytoma tumors are typically seen more in men than in women.
Angiomyolipoma is a genetically inherited form of kidney tumors. Most individuals that are diagnosed with angiomyolipoma are also diagnosed with a rare inherited disease called tuberous sclerosis. Tuberous sclerosis can cause tumors throughout the body, not just on the kidney.
Fibroma tumors are tumors of the tissue. They are more common in women than in men.
Lipoma tumors grow within the fat cells and the surrounding tissue. They typically grow large and because of their size they become painful. They are more common in women than in men.