Mark R. Anderson, MD, MSc
Anthony T. Corcoran, MD
Robert G. Uzzo, MD
BASICS
DESCRIPTION
• Most renal masses are incidentally found preoperatively on routine axial imaging (eg, CT or MRI of the abdomen)
• Although rare today, some renal masses are 1st identified intraoperatively
– Typically associated with trauma or urgent cases where preoperative imaging was either not done or inadequate for renal visualization
EPIDEMIOLOGY
Incidence
• Renal cell carcinoma (RCC)
– 63,920 estimated new cases in 2014 (NCI data)
– Primarily occurs in 6th or 7th decade
– Male > Female (3:2)
– 4% of RCC are familial; majority are sporadic
– 10–20% higher incidence in African Americans
Prevalence
N/A
RISK FACTORS
• RCC
– Family history, smoking, obesity, hypertension, end stage renal disease (ESRD)
• For intraoperative renal mass consult, risk factors include:
– Pre-existing nonrenal primary cancer
Possible metastatic lesion on kidney
– Inheritable tumor syndrome
Associated renal tumor component
– Renal insufficiency preventing use of contrast during imaging
– Centrally located or small tumors initially missed on imaging
PATHOPHYSIOLOGY
N/A
ASSOCIATED CONDITIONS
• Polycystic kidney disease
– Autosomal dominant (autosomal dominant polycystic kidney disease) or recessive (autosomal recessive polycystic kidney disease)
• Inheritable tumor syndromes with renal and extrarenal manifestations
– Birt–Hogg–Dubé (BHD gene; 17p11)
Cutaneous lesions, lung cysts, spontaneous pneumothorax, colonic polyps, or cancer
– Hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC gene; 1q42) (aka: Reed’s syndrome)
Uterine leiomyoma and leiomyosarcoma, cutaneous leiomyoma and leiomyosarcoma
– Hereditary hyperparathyroidism-jaw tumor syndrome (CDC23 gene; 1q24–32)
Parathyroid tumor, fibroosseous mandibular and maxillary tumor, uterine tumor
– Papillary thyroid carcinoma with associated papillary renal neoplasia (1q21)
Papillary thyroid cancer, nodular thyroid disease
– Tuberous sclerosis complex (TSC1, 9q34)
Facial angiofibroma, subungual fibroma, hypopigmentation and café au lait spots, cardiac rhabdomyoma, seizure, mental retardation, CNS tubers, lymphangioleiomyomatosis
– VHL (VHL gene; 3p25)
Retinal and CNS hemangioblastomas, pheochromocytoma, pancreatic cyst and endocrine tumor, endolymphatic sac tumor, epididymal and broad ligament cystadenomas
GENERAL PREVENTION
N/A
DIAGNOSIS
HISTORY
• Obtain history from operative team and review available medical and radiographic records
– Prior or current cancers
– Inheritable tumor syndromes
– History of renal or abdominal trauma
PHYSICAL EXAM
• Intraoperative evaluation—location of mass
– Check adrenal
– Intrarenal
– Extrarenal within Gerota fascia
– Perirenal
– Renal pelvis
DIAGNOSTIC TESTS & INTERPRETATION
Lab
Serum creatinine and eGFR
Imaging
• Review all preoperative ultrasound (US), contrast-enhanced CT, and/or MR if available
– If serial images available, determine growth rate to help define risk (1)[B]
Average yearly linear growth rate of 0.3 cm for all masses vs. 0.8 cm found in patients with progression
Masses with no growth under surveillance unlikely to metastasize
• Intraoperative US with color Doppler (use laparoscopic or finger probe in open surgery)
– Features suggesting malignant pathology
Purely cystic lesions without septation can be observed
Remove lesions with solid elements
– Color Doppler also useful to:
Assess flow to ipsilateral and contralateral kidney
Differentiate an isoechoic lesion with renal parenchyma since vessels are displaced around solid renal masses
Identifies deep vessels near the wall of the lesion that may be encountered during excision
ALERT
Obtain all available informatIon on renal function.
• Calculate overall renal function (GFR—Cockcroft–Gault equation; calculators available online) and classify CKD status.
• Status of contralateral renal unit presence, flow, and function.
• Enhancement characteristics on imaging.
Objectify risk:
• Overall survival vs. competing risks of death.
– Competing risks nomogram operationalized online at www.cancernomograms.com (2)[B].
• Remaining renal function.
– Can estimate percent functional volume preservation if partial nephrectomy planned as volume loss correlates well with ultimate renal function after partial nephrectomy (3)[B].
Diagnostic Procedures/Surgery
• Diagnostic procedures
– Consider intraoperative renal mass biopsy and frozen section analysis
Obtain core biopsy with biopsy gun
∼20% of intraoperative frozen sections of renal lesions nondiagnostic (4)[B]
Management options include active surveillance, ablation, or extirpation (Note: Renal biopsy and frozen section analysis yield poor tumor grade information)
Pathologic Findings
• Approximately 14% of incidentally found renal masses are benign depending on size (5)[B]
– 68% clear cell RCC
– Positive association between tumor size and:
Rates of clear cell RCC
Fuhrman grade for clear cell RCC
Tumor stage
DIFFERENTIAL DIAGNOSIS
• Renal masses (see Section I “Renal Mass” for more information)
– Abscess (acute or chronic)—consider history and available labs
– Angiomyolipoma (AML)—check for fat on imaging
– Adrenal lesion—check for presence of contralateral gland prior to removal—if unable beware of postoperative insufficiency
– Benign lesion—oncocytoma, etc.
– Calyceal diverticulum (chronic and infected can cause mass-like appearance with heavy perinephric reaction)
– Hemorrhagic cyst—may appear solid and pseudoenhance
– Lymphoma—may cause renomegaly
– Metastatic lesion from other primary tumor
– Pseudotumor (column of Bertin)
– Renal lobulations
– RCC, Wilms tumor
– Renal cysts
– Sarcoma (renal or retroperitoneal—including leiomyosarcoma and liposarcoma)
– Subcapsular hematoma—may be chronic especially with old trauma or extracorporeal shock wave lithotripsy
– Upper-tract urothelial carcinoma
– Vascular—hemangioma, renal artery aneurysm, malformation
• Perirenal
– Adrenal lesion or adrenocortical carcinoma
– Mesothelial cyst
– Teratoma
TREATMENT
GENERAL MEASURES
• What to do if called to the operating room emergen-tly to evaluate a renal mass (See Section III: Renal Mass, Intraoperative Consultation Algorithm)
• If patient unstable and involved kidney uninjured, defer to later date
• If films unavailable, safely defer if possible
• If unable to defer treatment—assess presence, function, and anatomy of both kidneys and consider biopsy
• Look at available films to see if pre-/postcontrast phases available
– If preoperative imaging suggests a solid, enhancing mass amenable to partial nephrectomy
Consider intraoperative biopsy and frozen section analysis
Reasonable to perform partial nephrectomy after family discussion (if present)
– Do not get fooled by hyperdense cyst or pseudotumor—see clinical pearls
• If no films, and cannot postpone intervention, consider biopsy
– If solid elements with flow on Doppler US, normal contralateral kidney and amenable to partial nephrectomy, then intervene
– If radical required for technical reasons, perform biopsy with frozen section pathologic analysis and possibly deferring intervention until permanent section results obtained
Unless absolute indication for radical nephrectomy (≥cT3, adjacent organ involvement, vascular compromise)
• Avoid the following:
– Rely on US as only test for radical nephrectomy (get biopsy)
– Rely solely on intraoperative single shot IVP to evaluate contralateral kidney
– Perform a radical nephrectomy because technically easier
– Assume presence, flow, or function of contralateral kidney
MEDICATION
First Line
N/A
Second Line
N/A
SURGERY/OTHER PROCEDURES
• Extirpative procedures
– Partial nephrectomy
Tumor enucleation may yield equivalent oncologic outcomes. Best used when mass locally confined on preoperative imaging, easily delineated intraoperatively, and do not appear to grossly invade beyond the pseudocapsule.
Frozen section analysis on margin if in question
– Radical nephrectomy
– Resection of mass adjacent to kidney ± partial or radical nephrectomy, if only way to get specimen out safely
• Surgical approach
– Attempt to use existing approach (laparoscopic/robotic) or incision
Convert from laparoscopic to open if needed for imperative indications only, otherwise may defer if oncologic risk low
If nephron sparing requires conversion for technical reasons, consider performing at later date with patient consent
• Remember to place perirenal closed suction drain for most nephron-sparing procedures
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
• Investigate adjuvant therapies or eligibility for adjuvant clinical trials based on pathology
• Follow functional (nephrologic) results
• If adrenalectomy was performed—beware of postoperative adrenal insufficiency
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
• Influenced by stage, grade, histology
• Margin status appears not to portend an adverse prognosis or increased local recurrence
• Local recurrence after resection is ∼2–3% after partial or radical nephrectomy
• 5-yr risks of recurrence for local or regional RCC fully excised are approximately:
– >95% for pT1, ∼85% for pT2, range from 40–60% for pT3b
COMPLICATIONS
• For partial and radical nephrectomy: Acute renal failure, need for dialysis
• Long-term risk of chronic renal insufficiency after radical nephrectomy associated with increased cardio- and cerebrovascular morbidity
• For partial nephrectomy: Urinary fistulas, and bleeding
• Major complications, including urine leak, increase with increasing tumor complexity
– Low complexity—6%
– Moderate complexity—11%
– High complexity—22%
FOLLOW-UP
Patient Monitoring
• NCCN guidelines (level of evidence 2B—lower level but consensus recommended)
– Every 6 mo for 2 yr, then annually for 5 yr
History and physical exam
Comprehensive metabolic panel
– At 2 yr as indicated based on recurrence risk
Chest and abdominal ± pelvic imaging
Risk-based follow-up clinical practice guidelines operationalized at www.cancernomograms.com
Patient Resources
N/A
REFERENCES
1. Smaldone MC, Kutikov A, Egleston BL, et al. Small renal masses progressing to metastases under active surveillance: A systematic review and pooled analysis. Cancer. 2012;118:997–1006.
2. Kutikov A, Egleston BL, Wong YN, et al. Evaluating overall survival and competing risks of death in patients with localized renal cell carcinoma using a comprehensive nomogram. J Clin Oncol.2010;28:311–317.
3. Simmons MN, Hillyer SP, Lee BH, et al. Functional recovery after partial nephrectomy: Effects of volume loss and ischemic injury. J Urol. 2012;187:1667–1673.
4. Krishnan B, Lechago J, Ayala G, et al. Intraoperative consultation for renal lesions. Implications and diagnostic pitfalls in 324 cases. Am J Clin Pathol. 2003;120:528–535.
5. Corcoran A, Russo P, Lowrance WT, et al. A review of contemporary data on renal masses—benign or malignant? Urology. 2013;81(4):707–713.
ADDITIONAL READING
NCCN guidelines: http://www.nccn.org/
See Also (Topic, Algorithm, Media)
• Birt–Hogg–Dubé Syndrome
• Renal Cell Carcinoma, General
• Renal Cell Carcinoma, Localized (T1–T2)
• Renal Cell Carcinoma, Locally advanced (T3–T4)
• Renal Cell Carcinoma, Metastatic (N+, M+)
• Renal Cell Carcinoma, Pediatric
• Renal Mass
• Renal Mass, Intraoperative Consultation Algorithm 
• Renal Masses, Benign, WHO Classification
• Von Hippel–Lindau Disease/Syndrome
CODES
ICD9
• 189.0 Malignant neoplasm of kidney, except pelvis
• 593.9 Unspecified disorder of kidney and ureter
• 753.10 Cystic kidney disease, unspecified
ICD10
• C64.9 Malignant neoplasm of unsp kidney, except renal pelvis
• N28.89 Other specified disorders of kidney and ureter
• Q61.9 Cystic kidney disease, unspecified
CLINICAL/SURGICAL PEARLS
• Traumatic hemorrhage into a cyst can mimic a hypoechoic, solid renal mass. Color Doppler can establish blood flow ruling out hemorrhagic cysts.
• Failing to check preoperative films if available as AML can often be distinguished by macroscopic fat on CT/MR.
• Avoid getting fooled by renal pseudotumor or adrenal lesion.
• Avoid expanding the goals of planned operation without consent or clearly thought out plan.