Benign kidney tumors (angiomyolipoma, renal cyst):
Renal cysts are the most common benign renal tumors and rarely require treatment. Rarely a renal (kidney) cyst will grow so large that it compresses either part of the kidney or surrounding structures causing pain or adverse effects. In this instance treatment may be indicated. Usually this can be accomplished with sclerosis (percutaneous or endoscopic) or decortication (unroofing of the cyst). Cysts should not simply be drained since they will almost always reaccumulate. Depending on the individual case a cyst requiring treatment can be approached through the back with a small scope (percutaneous endoscopic sclerosis) or with robotic decortication.
Angiomyolipoma (AML) is a relatively common benign tumor of the kidney. It is the only kidney tumor that can be diagnosed definitively by CT scan or MRI. This is due to the presence of fat found within all these tumors. Although these lesions are not malignant they confer a significant risk of spontaneous hemorrhage (bleeding), especially when they are larger than 5 cm (about 2.5 inches) in diameter. Options for treatment include angiographic embolization (blocking off the blood supply to the tumor through a catheterization procedure) or radical or partial nephrectomy. In the latter instance these procedures can be performed through a robotic approach. See Robotic Radical and Partial Nephrectomy of renal tumors for more information.