Back to Top Cystoscopy Blood in the urine can result from other health problems, such as kidney stones or traumatic kidney injury, so the doctor may order a cystoscopy to determine precisely where the internal bleeding is occurring. In cystoscopy, a long, thin, rigid or flexible optical scope is inserted through the urethra and into the bladder. The practitioner then makes a visual examination of the urethra, bladder, and kidneys to locate the site of bleeding. If a tumor is found through imaging or other procedures, a cell sample may be taken for microscopic examination. Physicians usually avoid performing needle biopsies of suspected kidney tumors because of the risk for bleeding or other complications.
Some tumors contain a fluid-filled cyst.
A small amount of this fluid can be drawn out of the cyst for examination by a pathologist, who will look for and identify the cancer cells. This can help the physician determine an appropriate treatment plan. While no longer common, a similar technique can be used to collect a sample of solid tissue from a noncystic tumor. Most studies suggest that the type of cancer cell indicates the relative aggressiveness of the disease. The tumors they produce are yellow to orange in color.