Ureteropelvic Junction Obstruction in a Polycystic Kidney with Duplicated System: Successful Outcome with Endoscopic Management.

Background: Autosomal dominant polycystic kidney disease is the most prevalent hereditary renal disease, associated with progressive renal insufficiency, usually leading to dialysis. It is rarely diagnosed with other renal abnormalities. We present a case of a 35-year-old woman with a duplicated left polycystic kidney, who had recurrent pain and pyelonephritis because of ureteropelvic junction (UPJ) obstruction of the upper moiety. Case Presentation: A 35-year-old female patient initially presented with left flank pain for 7 days. Evaluation demonstrated enlarged bilateral polycystic kidneys with the appearance of a duplicated system of the left kidney and UPJ obstruction of the upper moeity. She underwent endoscopic management, including balloon dilatation and stent placement. After stent removal she had no symptoms, and ultrasonography showed resolution of the upper pole hydronephrosis. Conclusion: Minimally invasive nephron sparing approaches for UPJ obstruction could delay the process of end-stage renal disease development in polycystic kidney disease patients who have additional congenital renal anomalies. Balloon dilatation should be considered as a feasible therapy for UPJ obstruction in polycystic kidney disease patients with duplicated systems.

Impact of a Wireless System Upon Verbal Communication in a Simulated Robotic Operating Theater.

OBJECTIVE: To compare the efficacy of communication via the standard Da Vinci Si speaker system with a wireless, hands-free audio system in a prospective blinded study. METHODS: Nine hundred and sixty surgical phrases were spoken in a simulated robotic operating room (OR), including 480 phrases expressed via the Da Vinci Si speakers and 480 phrases expressed through a wireless, hands-free system. Using a dual console robotic system, communication was evaluated. Wireless headsets were given to the console and assistant robotic console surgeons, bedside assistant, anesthesiologist, and circulating nurse. An accurate response was defined as hearing the phrase correctly and transcribing it on a data sheet. The primary outcome was the number of correct phrases recorded during the study and secondary outcomes included subjective clarity and effectiveness of communication reported using a Likert scale. RESULTS: Overall, the wireless, hands-free system increased the accuracy of communication (390/480 [81.3%]) compared to the conventional robotic system (310/480 [64.4%]; P <.001). The bedside assistant, anesthesiologist, and circulating nurse had significantly fewer correct phrases recorded than the assistant robotic console surgeon when using the robotic speakers (P <.05 for all). In contrast, there were no significant differences in the number of correct phrases recorded between different positions when using the wireless system. Subjectively, the wireless system resulted in improved clarity and effectiveness of communication (P = .021; P <.001, respectively). CONCLUSION: Robotic operating systems have intrinsic barriers to effective communication between the surgeon and the rest of the operating room team. Improved communication could reduce surgical errors and improve patient safety.

Do Illuminated Foot Pedals Improve the Speed and Accuracy of Pedal Activation During Endoscopic Procedures?

PURPOSE: Endourologic procedures such as percutaneous nephrolithotomy (PCNL) employ the use of foot pedals in low-light operating room (OR) settings. These pedals can be especially difficult to locate or distinguish when several pedals are present during a single operation. Improper instrument activation in the OR has led to serious complications ranging from unintentional electrocautery to patient burns and even an intraoperative explosion. This study evaluates the impact of color-coded illumination on speed and efficiency of foot pedal activation. MATERIALS AND METHODS: During a simulated PCNL procedure, the foot pedals for a C-arm, laser, and ultrasonic lithotripter (USL) were placed in random positions. Ten participants performed pedal activation in a randomized sequence. Objective outcomes included time to instrument activation, number of attempted pedal presses, number of incomplete pedal presses, and number of incorrect pedal presses. Subjective preferences for pedal illumination were also determined. Data were analyzed using Mann-Whitney U, Wilcoxon signed-rank, and Chi-square tests with p < 0.05 indicating statistical significance. RESULTS: Illuminated foot pedals were associated with decreases in the average activation time for all instruments collectively (3.95 seconds vs 6.49 seconds; p = 0.017) and individually (C-arm: 3.07 seconds vs 4.21 seconds; p = 0.006; laser: 13.04 seconds vs 15.18 seconds; p < 0.001; USL: 3.28 seconds vs 4.91 seconds; p < 0.001) compared with nonilluminated pedals. Illuminated pedals were associated with fewer attempted pedal presses (33.5 vs 39.5; p = 0.007) and incomplete pedal presses (1.5 vs 8.5; p = 0.002). The number of incorrect pedal presses decreased with illumination, but this did not reach statistical significance (0 vs 0.5; p = 0.08). Participants reported that illumination simplified pedal activation and recommended its use (p < 0.01). CONCLUSION: Color-coded illumination improved the speed and efficiency of foot pedal activation during simulated PCNL. Participants subjectively preferred using illuminated foot pedals for endourologic procedures and felt that they improved safety and efficiency.

Efficacy of antegrade and retrograde warm saline pyeloperfusion during renal cryoablation for ureteral preservation.

OBJECTIVE: Cryoablation of renal tumors adjacent to the ureter or pelvicalyceal system carries risks for thermal injury of the collecting system. Although cold antegrade perfusion has been described for radiofrequency ablation, warm saline perfusion for renal cryoablation has not been well-characterized. The purpose of this study was to determine the safety and feasibility of antegrade and retrograde warm saline perfusions during percutaneous renal cryoablation. MATERIAL AND METHODS: A retrospective review was performed on 136 patients treated with percutaneous renal cryoablation at a single academic institution between 2009 and 2015. Six patients undergoing antegrade (n=3) or retrograde (n=3) warm saline perfusion for protection of the collecting system were identified. Warm saline was perfused through a 4 French nephrostomy tube in the antegrade technique and through a 6 French end-hole catheter in the retrograde technique. Outcome measures were tumor recurrence rates, success of urothelial preservation, hospital stay, blood loss and procedural time. RESULTS: Four tumors were in the lower pole and two tumors in the middle pole. The mean distance from tumor to ureter was 6.8 mm (0.8-11.5 mm) and no patient developed ureteral stricture. There was no tumor recurrence at a median follow-up of 37.3 months (7-65). The median procedural time was 3 hours and 13 minutes. One patient in each group developed minor complications (Clavien I and II) and there were no major complications. CONCLUSION: This study demonstrates the feasibility of antegrade and retrograde warm saline perfusion for ureteral preservation during cryoablation, without compromising oncologic outcomes.

Conventional vs Computer-Assisted Stereoscopic Ultrasound Needle Guidance for Renal Access: A Randomized Crossover Bench-Top Trial.

PURPOSE: Ultrasound (US) guidance during renal access and mass biopsy reduces radiation exposure, but can be technically challenging. A needle guidance system might simplify these procedures. The purpose of this randomized crossover trial was to compare conventional and computer-assisted US needle guidance systems for renal access and mass biopsy. MATERIALS AND METHODS: Seventy-one subjects were randomized to perform renal access or mass biopsy on a phantom using conventional and computer-assisted US guidance in a crossover study design. The primary outcome was success rate including subgroup analysis by experience level. Secondary outcomes included total procedure time, time to hit target, number of course corrections, and total punctures. In addition, subjective preferences of participants were also collected. RESULTS: Procedure success rate was higher with the computer-assisted US than with conventional US for both novice (98.0% (48/49) vs 81.6% (40/49); p < 0.001) and experienced US users (100% (22/22) vs 81.8% (18/22); p < 0.001). Computer-assisted US significantly shortened the total procedure time (94.0 seconds vs 192.9 seconds; p ≤ 0.001), time required to hit the target (62.5 seconds vs 121.6 seconds; p ≤ 0.001), and the number of course corrections (0.56 vs 2.89; p < 0.001) compared with conventional US. Computer-assisted US did not significantly reduce the number of needle punctures (1.75 vs 2.39; p = 0.132). Seventy-three percent of subjects preferred the computer-assisted US system. CONCLUSION: A computer-assisted needle guidance system increases effective US targeting for renal access and mass biopsy for novice and experienced users.

Elevated Renal Pelvic Pressures during Percutaneous Nephrolithotomy Risk Higher Postoperative Pain and Longer Hospital Stay.

PURPOSE: Renal pelvic pressure may vary during percutaneous nephrolithotomy. We sought to determine the relationship of postoperative pain to endoscope caliber, renal pelvic pressure and hospital stay. MATERIALS AND METHODS: We reviewed the records of 20 percutaneous nephrolithotomies done under ureteroscopic guidance with renal pelvic pressure monitoring. The ureteroscope working channel was connected to a pressure transducer and used to determine renal pelvic pressure at baseline, when irrigating with a 26Fr rigid nephroscope and a 16Fr flexible nephroscope, and during suction. Patient demographics, operative characteristics, Likert pain scores and length of hospital stay were compared as stratified by average renal pelvic pressure. The Mann-Whitney U and Fisher exact tests were used with p <0.05 considered significant. RESULTS: A total of 220 measurements were recorded in 20 patients undergoing single access percutaneous nephrolithotomy. Mean patient age was 55.2 years (range 20 to 77) and mean body mass index was 32.4 kg/m2 (range 18 to 53.3). Rigid nephroscopy resulted in significantly higher average renal pelvic pressure than flexible nephroscopy (30.3 vs 12.9 mm Hg, p = 0.007). Average renal pelvic pressure was 30 mm Hg or greater in 7 patients (35%) undergoing rigid nephroscopy and in none (0%) undergoing flexible nephroscopy (p <0.01). Patients exposed to an average renal pelvic pressure of 30 mm Hg or greater during rigid nephroscopy had significantly higher average pain scores (p = 0.004) and longer hospital stays (p = 0.04) than patients with renal pelvic pressure less than 30 mm Hg. Average renal pelvic pressure 30 mm Hg or greater during rigid nephroscopy was also associated with a longer skin to calyx distance (105.5 vs 79.7 mm, p = 0.03). CONCLUSIONS: Knowledge of the factors that influence renal pelvic pressure and methods to control pressure extremes may improve patient outcomes during percutaneous nephrolithotomy.

Renal Pelvic Pressure in Percutaneous Nephrolithotomy: The Effect of Multiple Tracts.

INTRODUCTION: During percutaneous nephrolithotomy (PCNL), elevated renal pelvic pressures (RPPs) may spread infection through pyelovenous backflow whereas decreased pressures can hinder observation and increase bleeding. The purpose of this study was to evaluate the effects of multiple access tracts and different sized endoscopic equipment on RPP in a porcine model. MATERIALS AND METHODS: RPP was measured in one- vs two-tract access, rigid vs flexible nephroscopy, and suction vs no suction. Twenty trials were performed for each condition. An independent samples Mann-Whitney U-test was used to compare parameters, with p < 0.05 considered significant. RESULTS: With one tract, rigid nephroscopy resulted in higher mean pressures (31.35 mm Hg) than flexible nephroscopy (11.1 mm Hg; p < 0.001). The RPP was higher with rigid nephroscopy in one tract (31.35 mm Hg) than when two tracts were present (9.35 mm Hg; p < 0.001). In contrast, there was no difference in pressure during the use of a flexible nephroscope in one (11.1 mm Hg) vs two tracts (10.7 mm Hg; p = 0.63). Use of suction with the rigid nephroscope resulted in significantly lower pressures with one (-1.3 mm Hg) than with two tracts (1.8 mm Hg; p = 0.004). CONCLUSION: In PCNL, RPP is significantly affected by an additional tract during rigid nephroscopy and suctioning but not when using a flexible nephroscope. Understanding the effects of multiple tracts and equipment type on RPP may improve the safety of PCNL.

Jackets Off: The Impact of Laser Fiber Stripping on Power Output and Stone Degradation.

PURPOSE: To investigate the effect of laser fiber stripping on stone fragmentation and laser fiber power output. MATERIALS AND METHODS: In a benchtop simulation of laser lithotripsy, 20 BegoStone phantoms were positioned within a ureteral model and irradiated for 10 minutes at 8 Hz and 0.8 J. A freshly cleaved 365 µm laser fiber was used for all trials, with half of the fibers also undergoing stripping. Power output was measured at 1-minute intervals, beginning with an initial prelithotripsy recording at 0 minutes. Fiber tips were imaged with scanning electron microscopy. In a single-blinded manner, final masses of residual stone fragments were measured and used to quantify stone breakdown. Independent-sample Mann-Whitney U tests were performed with significance set at p < 0.05, comparing stripped and unstripped fiber tips with respect to power output and fraction of stone fragmentation. RESULTS: Mean power output after 1 minute of lasing was significantly greater in unstripped laser fibers (p = 0.015), while fibers, whether stripped or not, demonstrated no significant output differences prelithotripsy or at any time from 2 to 10 minutes. However, stripped laser fibers achieved significantly increased stone breakdown compared to unstripped fibers (p = 0.004), fragmenting 63 mg (25%) more of the initial stone mass per trial. CONCLUSIONS: Although unstripped laser fibers provided superior power output at 1 minute, output at all other time points was similar between stripped and unstripped fibers. However, despite similar optical output, stripped laser fibers achieved greater stone fragmentation, possibly due to improved contact between stone and fiber tip.

Predictors of narcotic use after percutaneous nephrolithotomy.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) is associated with significant variability in postoperative pain and subsequent narcotic use. The purpose of this study was to determine the factors associated with high narcotic use following PCNL. MATERIALS AND METHODS: A single-center retrospective review of patients undergoing initial PCNL between 2004 and 2014 was performed. Preoperative, intraoperative and postoperative factors associated with postoperative narcotic usage were analyzed. The primary outcome variable was mean narcotic usage, standardized to intravenous morphine-equivalents. Patients in the lowest 75th percentile were compared to those in the highest 25th percentile. Univariate and multivariate statistical analyses were performed, with p < 0.05 considered significant. RESULTS: When the 243 patients were compared from lowest to highest quartile, total narcotic use during the first 48 hour period was 2.3, 8.4, 15.6, and 41.7 mg of morphine-equivalents. On univariate analysis, predictors of high narcotic use included age 20-39 (p < 0.001), preoperative narcotic use (p < 0.001), presence of a postoperative complication (p = 0.044), and high stone burden (p = 0.002). Age < 20 (p < 0.001) and > 60 years (p = 0.014) were associated with low narcotic use. On multivariate analysis, age 20-39 (OR 6.87, 95% CI 2.22-21.23, p = 0.001), male gender (OR 2.47, CI 1.05-5.81, p = 0.037), and preoperative narcotic use (OR 3.27, CI 1.41-7.60, p = 0.006) were associated with higher opioid requirement. CONCLUSION: Patients who were aged 20-39, males, and those with prior narcotic exposure used the highest doses of narcotics postoperatively. Knowledge of the factors predictive of high narcotic usage may allow better preoperative management of patient expectations and more effective postoperative care to prevent the complications of high narcotic usage.

Percutaneous Externally Assembled Laparoscopic vs Laparoendoscopic Single-Site Nephrectomy in a Porcine Model: A Prospective, Randomized, Blinded, Study.

OBJECTIVE: To compare the outcomes between laparoendoscopic single-site (LESS) and a novel percutaneous externally assembled laparoscopic (PEAL) nephrectomy in an in vivo porcine model. MATERIALS AND METHODS: Ten female farm pigs were randomized to LESS nephrectomy (5) or PEAL nephrectomy (5). Operative times, estimated blood loss, and intraoperative and postoperative complications were compared. The surgeons used a Likert scale to grade difficulty of peritoneal access, port placement, tool assembly, hilar dissection, closure, and overall difficulty of surgery. Scar assessment was performed by a blinded plastic surgeon using the Vancouver Scar Scale. Descriptive statistics were reported as median and range. The Mann-Whitney U test was used for continuous and ordinal variables. A p value <0.05 was considered significant. RESULTS: Median operative time was significantly shorter in the PEAL group vs the LESS group (85 minutes vs 127 minutes, p = 0.03). Median Likert scores showed overall hilar dissection and nephrectomy to be significantly easier using PEAL compared with LESS (2 vs 9, p < 0.01 for both). The PEAL instruments left no visible scar at 5 feet in any animal, and only 1 out of 10 scars could be identified on physical examination. CONCLUSIONS: The PEAL surgical paradigm demonstrates nearly scarless outcomes while providing shorter operative times and easier performance than LESS nephrectomy in a porcine model.

High-Frequency Dusting Versus Conventional Holmium Laser Lithotripsy for Intrarenal and Ureteral Calculi.

INTRODUCTION: The efficiency of holmium laser lithotripsy for urolithiasis depends upon several factors, including laser pulse energy and frequency and stone composition and retropulsion. This study investigates the complex interplay between these factors and quantifies lithotripsy efficiency using different laser settings in a benchtop kidney and ureter model. MATERIALS AND METHODS: In vitro caliceal and ex vivo porcine ureteral models were constructed. Calcium oxalate monohydrate stones were fragmented using a 200-µm laser fiber. In the caliceal model, stone fragmentation and vaporization rates at settings of 0.6 J/5 Hz, 0.2 J/15 Hz, and 0.2 J/50 Hz were compared. In the ureteral model, fragmentation time, retropulsion rate, fragmentation rate, and fragmented stone weight were compared at settings of 0.6 J/5 Hz and 0.2 J/15 Hz. Retropulsive forces generated at 0.6 J/5 Hz, 0.2 J/15 Hz, and 0.2 J/50 Hz settings were compared. Analysis was performed using Student's t-test and one-way ANOVA. RESULTS: In the caliceal model, the 0.6 J/5 Hz setting fragmented and vaporized stones at a higher rate than the 0.2 J/15 Hz setting (0.072 vs. 0.049 mg/s; p < 0.001). However, when the 0.2 J energy setting was combined with the 50 Hz frequency, the fragmentation rate (0.069 mg/s) was similar to the fragmentation rate at 0.6 J/5 Hz (0.072 mg/s; p = 0.677). In the ureteral model, the 0.6 J/5 Hz setting produced higher fragmentation rates (0.089 vs. 0.049 mg/s; p < 0.001), but resulted in significantly lower fragmented stone weight overall (16.815 vs. 25.485 mg; p = 0.009) due to higher retropulsion rates (0.732 vs. 0.213 mm/s; p < 0.001). Retropulsive forces decreased significantly when pulse energy decreased from 0.6 to 0.2 J (0.907 vs. 0.223 N; p < 0.001). Frequency did not affect retropulsive force at 15 and 50 Hz settings (0.223 vs. 0.288 N; p = 0.509). CONCLUSIONS: Laser lithotripsy of calcium oxalate monohydrate stones in the ureter should be performed using the low-energy, moderate-frequency dusting setting to minimize retropulsion and maximize efficiency. In the renal calix, the low-energy high-frequency setting performed similarly to the high-energy low-frequency setting.

Kidney, Ureter, and Bladder (KUB): A Novel Grading System for Encrusted Ureteral Stents.

OBJECTIVE: To introduce a grading system (kidney, ureter, and bladder [KUB]) to identify encrusted stents that may require multiple surgeries, multimodal surgery, and operative time > 180 minutes for successful removal. METHODS: One hundred ten retained encrusted ureteral stents were retrospectively scored using the KUB grading system and this score was correlated with operative time, need for multiple surgeries or multimodal surgery, and stone-free rate. Data analysis was performed with t test, Mann-Whitney U test, and chi-square tests. A P value of <0.05 was considered statistically significant. RESULTS: Average indwelling stent time was 17.2 months (0.7-139.0). There were 83.6% of stents removed in a single surgery, with 63.0% of these requiring multimodal surgery. K score ≥ 3 was associated with multiple surgeries (odds ratio [OR] 3.59, P = .006), multimodal surgery (OR 2.44, P = .04), operative time > 180 minutes (OR 3.80, P = .001), and lower stone-free rate (OR 0.23, P = .02). U score ≥ 3 was associated with operative time > 180 minutes (OR 3.28, P = .003). B score ≥ 3 was associated with lower stone-free rate (OR 0.23, P = .020). Total score ≥ 9 was associated with multiple surgeries (OR 4.19, P = .001), operative time > 180 minutes (OR 3.45, P = .002), and lower stone-free rate (OR 0.13, P = .001). CONCLUSION: The KUB system identifies stents at risk for requiring multiple surgeries, multimodal surgery, and operative time > 180 minutes. It also correlates with stone-free rate. This grading system can help surgeons manage patient expectations and predict surgical complexity.

Diagnostic and prognostic role of immunohistochemical expression of napsin-A aspartic peptidase in clear cell and papillary renal cell carcinoma: a study including 233 primary and metastatic cases.

Napsin-A aspartic peptidase (napsin-A) is an aspartic protease that is predominantly expressed in the proximal renal tubules and type II pneumocytes of the lung. Recently, napsin-A was reported to be present in a proportion of renal cell carcinomas (RCCs). However, the utilization of napsin-A immunohistochemistry as a routine diagnostic tool for RCC, and the correlation of the level of napsin-A expression with histologic features have not yet been established. In the current study, using tissue microarrays composed of primary and metastatic RCCs, napsin-A expression was demonstrated in 86 of 222 (39%) clear cell RCCs (CRCCs) and 16 of 21 (76%) papillary RCCs (PRCCs), with a strong and diffuse staining pattern observed in PRCCs and a relatively weak and focal positivity in CRCCs. Compared with primary CRCCs, a comparable proportion of metastatic CRCCs retained napsin-A expression (45/132, 34%), suggesting the potential utility of napsin-A in the evaluation of metastatic tumors. The expression of napsin-A was also found to be inversely correlated to aggressive local tumor characteristics, such as advanced pathologic stage and high Fuhrman nuclear grade. We conclude that napsin-A may be a valuable immunohistochemical marker in the diagnosis of RCCs, particularly PRCC.

Enhanced recovery pathway for radical prostatectomy: Implementation and evaluation in a universal healthcare system.

INTRODUCTION: Enhanced recovery pathways are standardized, multidisciplinary, consensus-based tools that provide guidelines for evidence-based decision-making. This study evaluates the impact of the implementation of a clinical care pathway on patient outcomes following radical prostatectomy in a universal healthcare system. METHODS: Medical charts of 200 patients with prostate cancer who underwent open and minimally invasive radical prostatectomy at a single academic hospital from 2009 to 2012 were reviewed. A group of 100 consecutive patients' pre-pathway implementation was compared with 99 consecutive patients' post-pathway implementation. Duration of hospital stay, complications, post-discharge emergency department visits and readmissions were compared between the 2 groups. RESULTS: Length of hospital stay decreased from a median of 3 (inter-quartile range [IQR] 4 to 3 days) days in the pre-pathway group to a median of 2 (IQR 3 to 2 days) days in the post-pathway group regardless of surgical approach (p < 0.0001). Complication rates, emergency department visits and hospital readmissions were not significantly different in the pre- and post-pathway groups (17% vs. 21%, p = 0.80; 12% vs. 12%, p = 0.95; and 3% vs. 7%, p = 0.18, respectively). These findings were consistent after stratification by surgical approach. Limitations of our study include lack of assessment of patient satisfaction, and the retrospective study design. CONCLUSIONS: The implementation of a standardized, multidisciplinary clinical care pathway for patients undergoing radical prostatectomy improved efficiency without increasing complication rates or hospital readmissions.

Aldehyde dehydrogenase 1 expression in primary and metastatic renal cell carcinoma: an immunohistochemistry study.

BACKGROUND: ALDH1 has been shown to be a cancer stem cell marker, and its expression correlates with prognosis in a number of malignancies. We aimed to evaluate the expression of ALDH1 in a cohort of primary and metastatic RCC specimens, and to correlate expression with pathological outcomes such as tumor stage and grade, and clinical outcomes such as progression free survival. METHODS: Three tissue microarrays were constructed from 244 RCC specimens, taken from 1985 to 2006. Samples were stained using an ALDH1 monoclonal antibody and expression was quantified by degree of staining. Membrane and cytoplasm staining were considered separately. A retrospective chart review enabled correlation with clinical outcomes. RESULTS: ALDH1 expression did not vary significantly based on tumor stage (P = 0.6274) or grade (P = 0.1666). ALDH1 showed significantly more membranous expression in clear cell RCC versus other subtypes (P < 0.0001), as well as in the primary setting compared to metastases (P = 0.0216). In terms of progression free survival, no significant differences were seen based on ALDH1 expression levels. In a subanalysis of clear cell tumors, ALDH1 membranous expression was decreased in tumors of higher stage (P = 0.0233). CONCLUSIONS: ALDH1 may be useful in characterizing RCC tumors as clear cell subtype. However, unlike in other malignancies, ALDH1 may not be useful in prognosticating renal cancers. The clinical significance of decreased ALDH1 expression in the high stage and metastatic setting remains to be determined in further investigations.

Enhancer of zeste homolog 2 expression is associated with metastasis and adverse clinical outcome in clear cell renal cell carcinoma: a comparative study and review of the literature.

CONTEXT: Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase mediating chromatin condensation and epigenetic modulation, is overexpressed in various human carcinomas and is associated with adverse clinicopathologic characteristics and biologic behavior. The expression of EZH2 in renal cell carcinomas (RCCs) has not been fully characterized yet. OBJECTIVE: To evaluate the prognostic role of EZH2 in RCC by analyzing the immunohistochemical staining pattern of the marker in relation to pathologic features and clinical outcome. DESIGN: We correlated the immunolabeling of EZH2 with multiple clinicopathologic features, including Fuhrman nuclear grade, pathologic stage, metastatic status, and clinical outcome in 223 clear cell RCCs (CRCCs) and 21 papillary RCCs, by using tissue microarrays of primary and metastatic cases. RESULTS: Most CRCCs (75%) showed positive EZH2 staining, with most primary tumors showing focal staining in comparison to nonfocal staining in metastatic cases. In primary tumors, EZH2 expression was associated with higher nuclear grade and lower pathologic stage. Metastatic tumors showed a higher number of positive cases (81% versus 67%) and a more diffuse and more intense pattern of staining than primary CRCCs. For the 22 locally advanced primary tumors (T3/4) and 43 metastatic RCCs, patients who experienced RCC-related deaths significantly overexpressed the marker in comparison to patients who did not experience RCC-related mortality. CONCLUSIONS: By showing that EZH2 expression is associated with increased metastatic potential and a worse clinical outcome, this study suggests that EZH2 can serve as a prognostic biomarker for RCC, thus confirming it as a key molecule driving oncogenesis and metastasis.

Extensive renal infarction following percutaneous biopsy of a small renal mass: A case report.

Percutaneous renal biopsy has become increasingly used particularly in patients undergoing active surveillance for small renal masses. We present a patient, who was recently diagnosed with laryngeal squamous cell carcinoma, with significant complication following biopsy of a solid renal mass. The patient was planned for nephron-sparing surgery that was converted to radical nephrectomy due to extensive renal infarction secondary to significant subcapsular hemorrhage inflicted by the biopsy.