Kidney lesions, also known as masses or tumors, can come from spreading cancerous cells. They also arise from fluid-filled growths called cysts. Most commonly, lesions consist of cysts, which are benign (noncancerous). Solid lesions turn out to be cancerous over 80 percent of the time, notes Urology Health Foundation. Doctors usually do not even biopsy solid lesions before removing them, because of the risk of false negatives and because of how rarely they are caused by anything else.
Any anomalous growth inside the kidney is considered a lesion. Risk factors for having lesions that turn out to be cancerous include smoking, obesity, high blood pressure, a family history of kidney cancer, diet with fried meats or high caloric intake, chronic kidney failure or dialysis. Tuberous sclerosis and Von Hippel-Linday syndrome are two less-common causes, according to Urology Health Foundation.
If a kidney lesion turns out to be cancerous, and if the cancer has only taken up residence inside the kidney, removal, ablation and monitoring are the three most common treatment options. Removal is the standard treatment option and takes place via a nephrectomy, either taking out part of the kidney or taking the whole organ out. The philosophy behind partial removal is to get rid of the cancer, while leaving as much healthy kidney tissue in the body as possible, as stated by Urology Health Foundation. Ablation destroys the tumor without taking it out, and monitoring involves keeping an eye on the tumor to see if it begins to spread elsewhere in the body, states Urology Health Foundation.