1. Mark Monahan, M.D. Virginia Urology
Renal Masses
Mark Monahan, M.D.
Virginia Urology

2. Campbell-Walsh Urology, Tenth Edition

3. Outline Differentiating benign from malignant lesions
RCC epidemiology, evaluation and primary treatment
Renal cysts
Angiomyolipoma
What’s New in 2017

4. Initial Evaluation and Imaging
With proper history and imaging, primary care physicians can correctly identify the majority of renal masses, which are simple cysts (50 percent by 50 years old)
If the renal lesion in question appears cystic, it must be characterized as simple or complex (Bosniak classification)
Any renal mass that is not clearly a simple cyst by strict ultrasound criteria warrants evaluation by CT/MRI (if possible) and urology referral

5. Imaging
A renal mass protocol CT of the abdomen and pelvis are required for the initial work-up and staging (+chest imaging if suspicious for RCC)
MRI is generally used to evaluate for tumor thrombus in the renal vein and IVC, but may also be used when CT contrast is contraindicated
A central mass may suggest urothelial carcinoma and therefore urine cytology and endoscopic evaluation is generally considered
Bone scan, brain imaging and PET scans are not a routine part of initial evaluation

6. CT Limitations
In one study, the rate of contrast nephropathy in patients with a GFR > 40 was 0.6% and < 40 was 4.6%
Threshold of 45 is often the cut-off for many radiologists
CIN is 3rd most common cause of hospital acquired renal failure (usually after intra-arterial injection)

7. MRI Limitations
GFR is (stage 3 chronic kidney disease): use minimum dose of gadolinium (20 mL)
GFR is less than 30 (stages 4 and 5 chronic kidney disease): gadolinium is NOT recommended, unless the patient is on hemodialysis
Minimal risk of nephrogenic systemic fibrosis (NSF) in patients with renal failure (Deo et al found a risk of 2.4% in pts with ESRD)

8. Enhancing Renal Mass
In general, any mass that enhances by more than 15 Hounsfield units should be considered RCC until proven otherwise and warrants referral to a urologist

9. MRI Enhancement

10. Epidemiology
About 64,000 new cases of kidney cancer will occur in 2017
40,610 in men and 23,380 in women
About 14,400 people (9,470 men and 4,930 women) will die from this disease
Kidney cancer is among the 10 most common cancers in men and women
Lifetime risk for developing kidney cancer is about 1 in 63 (1.6%). This risk is higher in men than in women.
Rate of new kidney cancers has been rising since the 1990s, although this seems to have leveled off in the past few years. Part of this rise was probably due to the use of newer imaging tests such as CT scans, which picked up some cancers that might never have been found otherwise. The death rates for these cancers have gone down slightly since the middle of the 1990s.
Median age at diagnosis is 64 years

11. Epidemiology, continued
RCC is the most lethal of the urologic cancers
Traditionally, ~40% of patients with RCC ultimately die of their disease. Stage dependent (97%-8%)
The increased incidence in RCC is largely due to detection of small, localized tumors
85% of RCC’s are clear cell, followed by papillary, chromophobe and collecting duct tumors

12. Risk Factors
Most commonly cited environmental risk factor is tobacco exposure, with a relative risk of compared with controls
Multiple studies have also shown that RCC is more common among the obese, those with low socioeconomic standing and an urban background
Causative factors have not been identified
Other suggested etiologic factors include viruses, lead compounds, aromatic hydrocarbons, contrast agents, radiation and anti-hypertensive medications
Moderate alcohol, fruit and vegetables and fatty fish consumption may reduce risk of RCC

13. Risk Factors, continued
Male-to-female predominance of 3:2
Incidence is percent higher in African Americans
Incidence is higher in those with a history of Wilms’ tumor, acquired renal cystic disease and in those with end-stage renal failure
Relative risk of 2.9 for individuals with a first- or second-degree relative with RCC
The study of several hereditary types of RCC, including von Hippel- Lindau disease (VHL), has led to significant advances in the understanding of the molecular genetics of RCC

14. Presentation
Classic triad of flank pain, gross hematuria and a palpable abdominal mass is now rare
Incidental detection accounts for more than 50% of RCC cases
Usually organ confined with improved prognosis
Signs of metastatic disease may include bone pain, adenopathy, or hemoptysis
Paraneoplastic syndromes are found in 20% of patients, most commonly hypertension, anemia and hypercalcemia, hepatic dysfunction

15. Initial Evaluation
A thorough physical examination should be performed with special attention to detecting supraclavicular adenopathy, an abdominal mass, lower extremity edema, a varicocele or subcutaneous nodules
Laboratory evaluation includes a CBC, comprehensive metabolic panel, coagulation profile and urinalysis
Imaging: CT/MRI

16. Renal Mass Biopsy
20-25% of clinical stage 1 renal masses are benign; if < 1cm 46% benign (Frank, J Urology 2003)
Biology of renal masses are heterogeneous
Traditionally served a limited role due to high false neg rate
Used for suspected renal mets, abscess or lymphoma
False neg rate now improved with rare cases of needle tract seeding
10-15% still indeterminate

18. Primary Treatment of Localized Disease
Surgical resection remains the gold standard therapy for clinically localized RCC
Radical nephrectomy includes resection of the kidney, perirenal fat within Gerota’s fascia, regional lymph nodes and the ipsilateral adrenal gland
Can be performed either open or laparoscopically
Adrenal gland can generally be spared if it appears normal on imaging

19. Nephron-Sparing Surgery
Nephron-sparing surgery (NSS) was originally indicated only in clinical settings in which a radical nephrectomy would render the patient anephric
Multiple studies have now shown that NSS has equivalent outcomes to radical nephrectomy when used for tumors up to 7 cm in greatest diameter
Relative indications for NSS have now been expanded to include those patients with bilateral RCC, familial RCC, CRI, severe HTN or DM, reflux or hydronephrosis in the contralateral kidney, or those with tumors ≤4-5 cm and a preference for NSS

20. TNM Staging T1 ◦ T1a: tumor confined to kidney, <4 cm
T1b: tumor confined to kidney, >4 cm but <7 cm
T2: limited to kidney >7 cm◦ T2a: tumor confined to kidney, >7 cm but not >10 cm
T2b: tumor confined to kidney, >10 cm
T3: tumor extension into major veins or perinephric tissues, but not into ipsilateral adrenal gland or beyond Gerota's fascia ◦ T3a: Tumor grossly extends into the renal vein or its segmental (muscle-containing) branches, or tumor invades perirenal and/or renal sinus fat but not beyond the Gerota fascia
T3b: spread to infra diaphragmatic IVC
T3c: spread to supra diaphragmatic IVC or invades the wall of the IVC
T4: involves ipsilateral adrenal gland or invades beyond Gerota's fascia

21. T1a
Case courtesy of Dr Ahmed Abd Rabou, Radiopaedia.org, rID: 50396

22. T1b
Case courtesy of Dr Roberto Schubert, Radiopaedia.org, rID: 14439

23. T2
Case courtesy of Dr Ian Bickle, rID: 26207

24. Nephron-Sparing Surgery
NSS can be performed either open or laparoscopically
Robotic assistance now more frequently used to more accurately excise renal tumors while decreasing ischemia time and blood loss

25. Other Treatment Options
Cryoablation and radiofrequency ablation have gained acceptance as treatment options for small renal masses, especially in patients of advanced age or those with significant comorbidities that may not tolerate conventional surgery
Both can be performed percutaneously or laparoscopically
Long-term follow-up remains limited at this time, but most series report low rates of local recurrence, although some patients have required repeated treatments
Surveillance has also emerged as a reasonable option for patients with small (<3 cm) renal masses who are elderly or poor surgical candidates
Multiple studies have demonstrated an average growth rate of 3-4 mm per year and progression to metastatic disease in 1% or less after several years of follow-up
Not generally considered appropriate for masses larger than 3 cm, poorly marginated tumors, or for younger patients who are able to tolerate treatment

27. Outcomes after Surgery
Estimated 5-year survival rates for surgically treated localized RCC is 96% for stage I disease and 82% for stage II disease
Prognostic factors include tumor grade, stage, presence of regional nodal involvement, and evidence of metastatic disease at presentation

28. Treatment Outcomes
Approximately 1/3 of patients who undergo resection will have a recurrence
Most common site of distant recurrence is the lung and median time to relapse is 1-2 years
This has led to guidelines and recommendations for continued surveillance with periodic bloodwork, chest imaging and CTs following treatment
Recent evidence suggests that follow-up for small tumors (<4 cm) may safely be stopped after several years

29. Other Solid Renal Masses
The most common benign solid renal lesion is oncocytoma
Solid masses with identifiable areas of fat density are classified as angiomyolipomas
Solid renal masses may also represent metastatic disease or lymphoma (biopsy appropriate

30. Angiomyolipoma

31. Epidemiology of Renal Angiomyolipoma
The prevalence in autopsies is 0.3%, with ultrasound screening 0.1%. Women are much more frequently affected than men. Age peak 50– 60 years.
45–80% of patients with tuberous sclerosis have (bilateral) asymptomatic angiomyolipomas. In tuberous sclerosis, there is an equal distribution between men and women, age peak 30 years.
Signs & Symptoms
Flank pain
Potentially life-threatening hemorrhage due to spontaneous rupture into the retroperitoneum (Wunderlich's syndrome)
Pregnancy increases the risk of rupture.

32. Diagnosis of Renal Angiomyolipoma
Sonography of the Kidney:
Sonography of the kidneys shows an echogenic mass in the kidney, caused by the high fat content.
CT-Abdomen: The fat content typically causes a hypodense mass in the kidney with -20 to -80 HU, this enables the differentiation to renal cell carcinoma
Calcifications are rare in renal angiomyolipoma.
MRI and Angiography useful as well

33. Angiomyolipoma CT
Case courtesy of Dr Abdallah Khateeb, rID:

34. Renal Angiomyolipoma Treatment
Conservative Treatment: Annual imaging controls are possible with angiomyolipomas less than 4 cm and mild symptoms. The annual growth rate is about 5%, in tuberous sclerosis up to 20%.
Partial Nephrectomy: indicated in angiomyolipomas of >4 cm, severe symptoms or in tumors of uncertain diagnosis.
Selective embolization: possible minimally invasive treatment option. Sometimes, a relapse is possible after embolization. Rarely, percutaneous drainage of necrosis is necessary.
Emergency nephrectomy: necessary in rupture of angiomyolipoma with life- threatening bleeding.

35. Renal Cysts

36. Campbell-Walsh Urology, Tenth Edition

38. Case courtesy of Dr. David Cueta, rID: 274479
Case courtesy of Dr. Ian Bickle, rID: 21139

39. Bosniak II
Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 21712

40. Bosniak IIf
Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 23385
Case courtesy of Dr Usman Bashir, Radiopaedia.org, rID: 18823

41. Bosniak III
Slideplayer.com

42. Bosniak IV
Case courtesy of Dr Andrew Dixon, Radiopaedia.org, rID: 23402

44. Thank you