Most kidney tumors, both benign and malignant, do not cause any symptoms at all unless they grow to a quite large size, according to the American Cancer Society. A large mass may cause blood in the urine and pain on one side of the lower back. Other symptoms may include fatigue, loss of appetite, weight loss, anemia and persistent fever, but these symptoms are more commonly associated with malignant kidney masses.Continue Reading
The kidneys cannot be palpated during a physical examination, so even large masses cannot be readily detected, explains the American Cancer Society. Kidney masses can be visualized on ultrasound or computed tomography scans. The most common type of benign kidney mass is a simple cyst, notes the Urology Care Foundation. A cyst is a fluid-filled mass. The cystic nature of most kidney cysts can be identified on an ultrasound examination. More than 80 percent of solid kidney masses are malignant. Diagnosis of a solid mass as malignant or benign generally requires a biopsy.
There are three kinds of solid benign kidney masses, states Urology at UCLA. Renal adenomas are very small, slowly growing masses that are often mistaken for malignant renal cell carcinomas. Oncocytomas often grow to very large sizes and are usually treated by removal of the affected kidney. The third type is called an angiomyolipoma, which most commonly affects people with tuberous sclerosis.Learn more about Conditions & Diseases