Clear-cell kidney cancer grows silently inside the kidney filter. Early tumors rarely hurt, so the first clues usually show up in blood tests or urine color.

Painless blood is the hallmark. Urine can turn light pink, rust-brown, or contain small clots—often on and off, so many blame infection first.

Flank ache creeps in later. A dull, steady throb below the ribs can spread to the groin if the tumor gets big or bleeds.

Low-grade fever or night sweats can appear. You feel cold one minute, hot the next, yet the thermometer rarely spikes high.

Weight loss and fatigue tag along. Clothes feel looser, and naps don’t help, even when the appetite seems normal.

A swollen lump or heavy feeling on one side can show up if the cancer grows large or presses on nearby organs.

Late signs include a swollen leg, bone pain, or a cough—an alarm that the cancer has spread beyond the kidney.