Urology · University Urology, PC · Knoxville, TN
Kidney Mass Found on CT Scan
A kidney mass discovered incidentally on imaging is one of the most common urologic findings. Most are small and many are benign — but evaluation by a fellowship-trained urologic oncologist is essential to determine the right course of action.
What This Means
What Is a Kidney Mass?
A kidney mass (also called a renal mass) is any abnormal growth or lesion detected in the kidney on CT, MRI, or ultrasound. Most are discovered incidentally — found during imaging ordered for an unrelated reason such as abdominal pain or a screening scan.
Most kidney masses are small
The majority of incidentally discovered kidney masses are less than 4 cm. Small masses have a lower risk of malignancy and a range of management options including active surveillance, ablation, and surgery.
Not all kidney masses are cancer
Approximately 20–30% of small renal masses removed surgically turn out to be benign. Angiomyolipomas, oncocytomas, and cysts are common benign findings. Biopsy and advanced imaging help characterize the mass before treatment decisions are made.
Prompt evaluation matters
Kidney cancer is highly curable when caught early. Renal cell carcinoma confined to the kidney has a 5-year survival rate over 90%. Evaluation by a specialist who performs high volumes of kidney cancer surgery ensures you receive accurate staging and the most appropriate treatment recommendation.
Treatment Options
How Kidney Masses Are Managed
Active Surveillance
For small (<3 cm), slow-growing masses in older or higher-risk patients, structured monitoring with periodic imaging is guideline-supported and avoids the risks of intervention.
Robotic Partial Nephrectomy
Surgical removal of the tumor while preserving the healthy kidney. The preferred approach for most localized kidney tumors. University Urology is among the highest-volume partial nephrectomy centers in the country.
Ablation (Cryotherapy/RFA)
Image-guided needle destruction of the tumor using extreme cold or heat. Performed by our interventional radiology colleagues for small, favorably located masses in non-surgical candidates.
Radical Nephrectomy
Removal of the entire kidney when partial nephrectomy is not feasible. Performed laparoscopically or robotically at University Urology for minimally invasive recovery.
For complex cases including vena cava involvement, University Urology is the region’s only high-volume center for vena cava thrombectomy. See our kidney cancer treatment page for the full treatment overview.
Our Specialists
Kidney Cancer Surgeons at University Urology
Urologic Oncology
Dr. James M. Bienvenu
Partial nephrectomy, vena cava thrombectomy, complex kidney cancer
Urologic Oncology
Dr. Wesley M. White
Partial and radical nephrectomy, robotic surgery
Robotic Surgery
Dr. Jonathan W. Angelle
Partial and radical nephrectomy, kidney cancer surgery
Endourology
Dr. Ryan B. Pickens
Partial and radical nephrectomy, minimally invasive kidney surgery
Endourology
Dr. Eric C. Riedinger
Partial and radical nephrectomy, minimally invasive kidney surgery
Common Questions
Frequently Asked Questions
The radiologist report says "indeterminate mass." What does that mean?
Indeterminate means the imaging cannot definitively characterize the mass as benign or malignant. Further evaluation — typically MRI with contrast or a repeat CT with a renal mass protocol — is needed. A urologist will review the imaging and determine the next step.
My mass is small. Can I just watch it?
Active surveillance is a legitimate, guideline-supported option for small renal masses, particularly in older patients or those with significant health risks. The decision depends on mass size, imaging characteristics, your age, and your overall health. This is exactly the kind of individualized decision a urologic oncologist is trained to make.
What is partial nephrectomy and will I lose my kidney?
Partial nephrectomy removes only the tumor, preserving the rest of the kidney. It is the preferred surgical approach for most kidney masses and is performed robotically at University Urology. Most patients retain excellent kidney function after the procedure.
How quickly do I need to be seen?
Most incidentally discovered kidney masses are not emergencies, but evaluation should not be delayed more than a few weeks. Call our office and our scheduling team will match you with the right surgeon promptly — most kidney mass patients are seen within days of referral.
Kidney Mass on Imaging? See a Specialist.
University Urology is among the nation\'s highest-volume kidney cancer centers. Most patients are seen within days of referral.