Question: what does it mean when you have a lesion on your kidney?
Answer: Basic Facts about Kidney Cancer The terms "tumor," "mass," or "lesion" are used to describe an abnormal growth in the kidney. Tumors can be benign (non-cancerous) or malignant (cancerous). A fluid-filled sac, called a cyst, is the most common growth found in a kidney. Cysts are mostly not cancerous.