Pathologic concordance of sporadic synchronous bilateral renal masses. Urology. 2008;72:138-142. [PMID: 18336882 DOI: 10.1016/j.urology.2008.01.043]

Multiple and hereditary renal tumors: a review for radiologists

80% of renal carcinomas (RC) are diagnosed incidentally by imaging. 2-4% of "sporadic" multifocality and 5-8% of hereditary syndromes are accepted, probably with underestimation. Multifocality, young age, familiar history, syndromic data, and certain histologies lead to suspicion of hereditary syndrome. Each tumor must be studied individually, with a multidisciplinary evaluation of the patient. Nephron-sparing therapeutic strategies and a radioprotective diagnostic approach are recommended. Relevant data for the radiologist in major RC hereditary syndromes are presented: von-Hippel-Lindau, Chromosome-3 translocation, BRCA-associated protein-1 mutation, RC associated with succinate dehydrogenase deficiency, PTEN, hereditary papillary RC, Papillary thyroid cancer- Papillary RC, Hereditary leiomyomatosis and RC, Birt-Hogg-Dubé, Tuberous sclerosis complex, Lynch, Xp11.2 translocation/TFE3 fusion, Sickle cell trait, DICER1 mutation, Hereditary hyperparathyroidism and jaw tumor, as well as the main syndromes of Wilms tumor predisposition. The concept of "non-hereditary" familial RC and other malignant and benign entities that can present as multiple renal lesions are discussed.

Single-cell transcription analysis reveals the tumor origin and heterogeneity of human bilateral renal clear cell carcinoma

Bilateral renal clear cell carcinoma (BRCC) is a rare type of renal cell carcinoma (RCC) that accounts for only 1-5% of RCC cases and has a poor clinical prognosis. The origin, tumor microenvironment, cellular molecular features, and intra-tumoral heterogeneity of BRCC are still unclear. We downloaded BRCC single-cell transcriptome sequencing data from the gene expression omnibus database biochip GSE171306, containing 3,575 cells from left-sided clear cell renal cell carcinoma (ccRCC) and 3,568 cells from right-sided ccRCC, and used a series of R packages for data quality control (QC) and subsequent analysis of BRCC single-cell transcriptome data, including the use of the R packages Seurat and scCancer for cell QC, identification of major cell types, and cell annotation; R package scran for calculation of cell cycle scores; R package infercnv for malignancy scoring of tumor cells; R package ReactomeGSA for functional enrichment analysis; R package Monocle 2 for the analysis of cell differentiation trajectories; and R package CellphoneDB for the analysis of intercellular interactions. In this study, by analyzing the high-quality single-cell transcriptome data of BRCC, we identified 18 cell types and found that left- and right-sided ccRCC were approximately the same in terms of cell type and the number of each cell but differed significantly in terms of tumor cell malignancy score, tumor microenvironment, and cell stemness score. In the cell differentiation trajectory analysis of BRCC, we found that endothelial cells and macrophages play an extremely important role in its tumor progression. Further cell communication analysis was performed, and we found that it may signal through ligand-receptors, such as vascular endothelial growth factor-vascular endothelial growth factor receptor1 (VEGF-VEGFR1), MIF-(CD74-CXCR4), and growth arrest-specific protein 6-AXL, to influence the development of BRCC. The analysis of single-cell transcriptomic data of human BRCC suggests that left- and right-sided ccRCC may be of the same tumor origin, but the left-sided ccRCC is more malignant and has a better immune response.

Ipsilateral synchronous papillary and clear renal cell carcinoma: A case report and review of literature

BACKGROUND

There is limited information on ipsilateral synchronous papillary renal cell carcinoma (PRCC) and clear cell renal cell carcinoma (CCRCC). Therefore, these rare tumors are often misdiagnosed preoperatively as a single tumor with intrarenal metastasis or some other diseases. Effective management and long-term overall survival might be affected because the prognosis of the two tumors differs.

CASE SUMMARY

We describe a case of ipsilateral synchronous PRCC and CCRCC with two histological variants in a 72-year-old man, whose mass was found incidentally, with no other chief complaints and vital signs were normal. Initial ultrasound revealed a hypoechoic lobular mass with a volume of 7.8 cm × 4.8 cm × 2.8 cm in the middle to lower pole of the left kidney. A subsequent contrast-enhanced computed tomography scan showed a single endophytic mass of 7.5 cm in diameter. The patient underwent laparoscopic left radical nephrectomy. A final diagnosis of ipsilateral synchronous PRCC and CCRCC was confirmed by pathological examination. There was no recurrence or metastasis after 25 mo follow-up.

CONCLUSION

We report a case of ipsilateral synchronous PRCC and CCRCC, and review related literature to estimate the prevalence of similar cases. The above descriptions may be expected to help understand the disease, and improve diagnosis in the future.

sABLATE: a simplified ABLATE score for prediction of complications and outcome in percutaneous thermal ablation of renal lesions

The aim of the study is to evaluate the performance of a simplified ABLATE score (sABLATE) in predicting complications and outcome with respect to RENAL, mRENAL, and ABLATE scores. This study included 136 renal lesions in 113 patients (M:F ratio = 2.5; mean age 70.8 years). 98 tumors underwent cryoablation at San Raffaele hospital between 01/2015 and 03/2020, while 37 underwent microwave ablation at San Paolo or Policlinico hospitals between 07/2016 and 03/2020. RENAL, mRENAL, ABLATE, and sABLATE scores were calculated using pre-procedural imaging. Data regarding complications and follow-up were registered. Mann-Whitney U test, ROC analyses, and logistic regression analyses were used for complications. Cox-regression analyses were performed for outcome. Mean tumor diameter was 23.2 mm. Mean and median RENAL, mRENAL, ABLATE, and sABLATE scores were 6.8 and 7, 6.9 and 7, 5.3, and 5, and 3.5 and 3, respectively. During a mean follow-up of 21.9 months (range 1-73), we registered 7 complications, 3 cases of residual disease, and 10 local tumor progressions. Mann-Whitney U test p values for complications for RENAL, mRENAL, ABLATE, and sABLATE were 0.51, 0.49, 0.66, and 0.056, respectively. ROC analyses for complications showed an AUC for RENAL, mRENAL, ABLATE, and sABLATE of 0.57, 0.57, 0.55, and 0.71, respectively. Regarding outcome, HR and p values of Cox-regression analyses were 1.30 and 0.36 for RENAL, 1.33 and 0.35 for mRENAL, 2.16 and 0.01 for ABLATE, 2.29 and 0.004 for sABLATE. sABLATE was the only score close to significance for complications, representing a progress even if not definitive. Regarding outcome, ABLATE confirmed its value, and sABLATE maintained validity despite being a simplification.

[Bilateral papillary renal cell carcinoma following kidney transplantation: A case report]

With the continuous development of kidney transplantation technique, the survival time after kidney transplantation is gradually prolonged. Thus, the malignant tumor has been the important influencing factor on the long-term survival for kidney transplantation patients. Renal cell carcinoma is a relatively common tumor after kidney transplantation. Besides, clear cell renal cell carcinoma and papillary renal cell carcinoma are the relatively common pathological types for renal cell carcinoma following kidney transplantation. However, bilateral renal cell carcinoma following kidney transplantation is comparatively rare. In this article, we presented a case of bilateral papillary renal cell carcinoma, which occurred after kidney transplantation. And the diagnosis and treatment were introduced in detail. The patient was 37 years old, and he underwent kidney transplantation 13 years ago in our hospital, because of kidney failure. After kidney transplantation, he had regular medical check-up every year. In this year, his urological ultrasound results indicated bilateral renal tumors. And then, he received abdominal and pelvic computed tomography, and the result also showed bilateral renal tumors, which were likely to be malignant tumors. After adequate consultation, the patient chose surgical treatment. The patient received long-term immunosuppressive therapy, because of kidney transplantation. Considering this, the surgeon decided to choose a staging surgical treatment, in order to reduce the bad influence of one-stage surgery. Then, the patient first underwent retroperitoneal laparoscopic radical nephrectomy for right renal tumor in our hospital, and he had no complications after operation. The pathological results showed papillary renal cell carcinoma. He was discharged successfully. He underwent retroperitoneal laparoscopic radical nephrectomy for left renal tumor in our hospital one month later, and he had no complications after operation. The pathological results also showed papillary renal cell carcinoma. He was discharged successfully two days after surgery. In the 3-month follow-up, the patient was recovering well. To sum up, the incidence of bilateral renal cell carcinoma following kidney transplantation is relatively rare, and bilateral radical nephrectomy is effective and safe treatment. Above all, it is the patient's condition that determines the choice of staging surgery or simultaneous surgery.

Retroperitoneal laparoscopic partial nephrectomy for unilateral synchronous multifocal renal carcinoma with different pathological types: A case report

BACKGROUND

The majority of renal cell carcinomas are single lesions; unilateral synchronous multifocal renal carcinoma (USMRC) is rarely reported and poses a treatment challenge for urological oncologists.

CASE SUMMARY

A 56-year-old man was hospitalized for pain and discomfort in the right kidney area for 6 d. Contrast-enhanced computed tomography demonstrated cT1a renal tumors at the lower pole of the right kidney and a cT1b renal tumor at the middle dorsal portion of the right kidney. The patient underwent retroperitoneal laparoscopic partial nephrectomy (RLPN). There were no complications peri-operatively. Histopathology revealed a low-grade, pathologic stage T1a (pT1a), clear cell renal cell carcinoma at the lower pole of the right kidney and a pT1b, chromophobe renal cell carcinoma at the middle dorsal portion of the right kidney. No tumor bed recurrence or metastasis was observed on imaging and his renal function remained stable during the 12-mo follow-up period.

CONCLUSION

RLPN is a safe, effective, and feasible for the management of USMRC, which can obtain equivalent oncological results with optimal renal function preservation.

The Clinicopathologic and Molecular Landscape of Clear Cell Papillary Renal Cell Carcinoma: Implications in Diagnosis and Management

BACKGROUND

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently described tumor entity. Several questions remain about its epidemiology, molecular features, and clinical behavior.

OBJECTIVE

To comprehensively evaluate clinicopathologic and molecular features of CCPRCC, and compare it with more common kidney cancer subtypes.

DESIGN, SETTING, AND PARTICIPANTS

We identified 89 CCPRCC patients and compared their clinicopathologic features with 1120 localized clear cell renal cell carcinoma (ccRCC) and 129 type 1 papillary renal cell carcinoma (pRCC) patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Nonparametric statistical testing was used to compare relevant features between tumor types. Overall, cancer-specific survival (CSS) and metastasis-free survival estimates were calculated from initial diagnosis using the Kaplan-Meier method. Patients with ipsilateral multifocal disease were explored further. A subset of CCPRCC tumors underwent genomic analysis and were compared with other RCC subtypes.

RESULTS AND LIMITATIONS

A higher proportion of female (45% vs 32%) and African-American (19% vs 3%) patients were observed in the CCPRCC cohort than in the ccRCC and pRCC cohorts. CCPRCC tumors also had increased odds of presenting with additional ipsilateral masses (odds ratio [OR]: 4.41 [confidence interval {CI}: 2.34, 8.15], p < 0.001) and bilateral disease (OR: 4.80 [CI: 2.40, 9.59], p < 0.001) compared with ccRCC tumors. On molecular analysis, CCPRCC tumors showed fewer somatic aberrations and a greater degree of mitochondrial DNA depletion. In multifocal CCPRCC tumors, histologic concordance among the different renal cell carcinoma masses was estimated at 44% (7/16), and none of the individuals presenting exclusively with CCPRCC tumors developed metastatic disease after 5 yr. In contrast, multifocal tumors with CCPRCC and other nonconcordant histologies were more likely to experience adverse outcomes (CSS, log rank p = 0.034).

CONCLUSIONS

CCPRCC is characterized by distinct molecular and epidemiologic features that could be used to refine current diagnostic approaches. Although their clinical course is generally indolent, multifocal CCPRCC tumors represent a unique diagnostic challenge. In this context, single-mass biopsies could miss concomitant aggressive disease, with a potential negative impact on patient outcomes. Furthermore, high discordance rates in multifocal CCPRCC tumors have important clinical implications in management.

PATIENT SUMMARY

We explored the molecular and clinical features of clear cell papillary renal cell carcinoma (CCPRCC) relative to other kidney cancer subtypes. While CCPRCC generally conveys a good prognosis, additional caution should be taken when it is diagnosed using biopsy if multiple kidney masses are present.

Bilateral Single-Stage Nephrectomy for Synchronous Bilateral Renal Cell Carcinoma

Bilateral synchronous renal cell carcinoma (RCC) is uncommonly encountered. Debate exists among urologists in managing these cases in a single surgery versus staged surgeries. We aim to report our experience in managing encountered cases using single-stage surgeries. Retrospective collection of cases with pathologically confirmed RCC that had single-stage bilateral renal surgery over the past 2 years. Three cases were identified. Patients were managed using bilateral transverse lateral lumbotomy. All patients did not have intraoperative or postoperative complications. Kidney function stayed stable after surgery. Single-stage bilateral renal surgery is a safe procedure. Bilateral transverse lateral lumbotomy allows for a fast and safe surgery with minimal complications. There is a possible histological dis-concordance in bilateral synchronous RCC.

Outcomes of Microwave Ablation for Small Renal Masses: A Single Center Experience

Purpose: To investigate the safety of microwave ablation (MWA) as an emerging technology for treating small renal masses. Materials and Methods: Patients with renal masses treated at a high-volume center with MWA between March 2015 and June 2019 were retrospectively identified. Safety, changes in renal function, primary treatment efficacy, and the natural history of imaging characteristics of masses postablation were examined. Results: Forty-five patients underwent MWA during the study period. Median age was 71 years (range 31-87). Median RENAL nephrometry score was 6 (range 4-9) with mean tumor size 2.6 ± 0.7 cm. Thirty-three percent of tumors were within 4 mm of the collecting system. Median total microwave energy applied was 400 W (range 105-2600 W). There was no significant change in creatinine (p = 0.21) or glomerular filtration rate (GFR) (p = 0.09) from preoperative to postoperative day 1 (POD#1) levels. There was a statistically but not clinically significant decrease in hemoglobin from preoperative to POD#1 levels (estimated -0.06 from 7 days before procedure to POD#1, p = 0.02). There was no durable change in creatinine (p = 0.16) or GFR (p = 0.72) at median follow-up of 7.5 months. There were 4 (9%) complications: three Clavien grade 1 and one Clavien grade 3 that led to loss of the kidney. Tumor size decreased postoperatively by an estimated -0.03 cm/month (range 0-1.9 cm, p < 0.01). Initial technical success was 100%. Primary treatment efficacy was 94%. Conclusion: MWA shows promise as an alternative thermal ablative technique with excellent short-term outcomes.

Synchronous sporadic bilateral multiple chromophobe renal cell carcinoma accompanied by a clear cell carcinoma and a cyst: A case report

BACKGROUND

Renal cell carcinomas are usually unilateral. However, they are bilateral in 2% to 4% of sporadic cases and is considerably more common in familial cases. Synchronous sporadic bilateral multiple chromophobe renal cell carcinoma (CHRCC) with different subtypes is rare.

CASE SUMMARY

In this case report, we describe a case of synchronous bilateral CHRCC with two histological variants, accompanied by a clear cell carcinoma and a cyst in a 50-year-old male. The patient underwent retroperitoneal laparoscopic bilateral nephron-sparing surgery and there was no serious postoperative renal dysfunction.

CONCLUSION

We report a rare case of synchronous bilateral CHRCC with two histological variants associated with a clear cell carcinoma and a cyst.

Identification and Validation of Radiographic Enhancement for Reliable Differentiation of CD117(+) Benign Renal Oncocytoma and Chromophobe Renal Cell Carcinoma

Purpose: The diagnostic differential for CD117/KIT(+) oncocytic renal tumor biopsies is limited to benign renal oncocytoma versus chromophobe renal cell carcinoma (ChRCC); however, further differentiation is often challenging and requires surgical resection. We investigated clinical variables that might improve preoperative differentiation of CD117(+) renal oncocytoma versus ChRCC to avoid the need for benign tumor resection.Experimental Design: A total of 124 nephrectomy patients from a single institute with 133 renal oncocytoma or ChRCC tumors were studied. Patients from 2003 to 2012 comprised a retrospective cohort to identify clinical/radiographic variables associated with renal oncocytoma versus ChRCC. Prospective validation was performed among consecutive renal oncocytoma/ChRCC tumors resected from 2013 to 2017.Results: Tumor size and younger age were associated with ChRCC, and multifocality with renal oncocytoma; however, the most reliable variable for ChRCC versus renal oncocytoma differentiation was the tumor:cortex peak early-phase enhancement ratio (PEER) using multiphase CT. Among 54 PEER-evaluable tumors in the retrospective cohort [19 CD117(+), 13 CD117(-), 22 CD117-untested], PEER classified each correctly as renal oncocytoma (PEER >0.50) or ChRCC (PEER ≤0.50), except for four misclassified CD117(-) ChRCC variants. Prospective study of PEER confirmed 100% accuracy of renal oncocytoma/ChRCC classification among 22/22 additional CD117(+) tumors. Prospective interobserver reproducibility was excellent for PEER scoring (intraclass correlation coefficient, ICC = 0.97) and perfect for renal oncocytoma/ChRCC assignment (ICC = 1.0).Conclusions: In the largest clinical comparison of renal oncocytoma versus ChRCC to our knowledge, we identified and prospectively validated a reproducible radiographic measure that differentiates CD117(+) renal oncocytoma from ChRCC with potentially 100% accuracy. PEER may allow reliable biopsy-based diagnosis of CD117(+) renal oncocytoma, avoiding the need for diagnostic nephrectomy. Clin Cancer Res; 24(16); 3898-907. ©2018 AACR.

Pathological heterogeneity in sporadic synchronous renal tumors: Is the histological concordance predictable?

OBJECTIVE

To evaluate the pathological concordance rate of multiple synchronous renal masses (MSRM) presumed to be sporadic and to analyze predictive factors of concordance.

MATERIAL AND METHODS

We identified from our institutional database patients with sporadic MSRM treated at our center between January 2000 and December 2015. All tumors were reviewed by a dedicated uropathologist. Pathological concordance rate was analyzed regarding clinical characteristics and preoperative imaging.

RESULTS

We included 112 patients: 50 had unilateral synchronous renal masses and 62 bilateral synchronous renal masses. A total of 291 tumors were analyzed, with an average of 2.6 tumors per patient. Overall, the malignant concordance rate was 91.6%, the pathological concordance rate was 67.3% and the grade concordance rate was 62.5%. In univariate analysis, predictive factors of histological concordance were bilateral synchronous renal masses (odds ratio [OR] = 3.39; 95% CI: 1.06-10.8; P = 0.04), age<60 years (OR = 3.04; 95% CI: 1.2-7.7; P = 0.02) and ≥3 lesions (OR = 2.41; 95% CI: 1.03-5.68; P = 0.04). In multivariate analysis, age<60 remained significantly associated with histological concordance (OR = 3.84; 95% CI: 1.24-11.9; P = 0.02).

CONCLUSIONS

The histological concordance rate of MSRM is low. Age at diagnosis <60 years, bilateral lesions and ≥3 tumors are predictive factors of histological concordance, but the pathological diagnosis remains difficult to predict. This heterogeneity is important to take into account, particularly when choosing the treatment upon the renal biopsy results from a single lesion.

Bilateral renal cancers: oncological and functional outcomes

PURPOSE

The authors assessed the characteristics of bilateral renal cancers.

METHODS

From January 1995 to January 2015, 65 patients underwent surgery for bilateral renal cancers. Thirty-four of the patients had 36 synchronous tumors, while the remaining 29 had metachronous tumors. The mean age of the patients was 60 ± 11 years. There were 22 females and 43 males. In all cases, bilateral partial nephrectomies or unilateral nephrectomy and contralateral nephron-sparing surgery were performed.

RESULTS

The mean sizes of the synchronous tumors were 5.0 ± 2.7 and 4.7 ± 3.0 cm at the first and the second operations, respectively. The average diameters of the metachronous carcinomas were 6.6 ± 3.0 and 3.1 ± 1.6 cm at the initial and the second surgeries, respectively. Histologic concordance was 91.1 % in the synchronous and 96.5 % in the metachronous tumors. The mean postoperative creatinine levels increased by 116 %, while the GFR decreased by 44.8 % in synchronous tumors at the second operation. The mean postoperative creatinine levels increased by 42 %, while the GFR decreased by 30.4 % in metachronous carcinomas at the second operation. The mean follow-up time was 4.8 ± 3.7 years. During this period, distant metastases occurred in two patients with synchronous tumors and in six cases with metachronous tumors. Local recurrences were detected in one case of synchronous tumor and in four patients with metachronous carcinomas. The 5-year overall and tumor-specific survivals were 53 and 80 %, respectively.

CONCLUSIONS

In patients with bilateral renal carcinomas, the histologic concordance was 93.6 %. The bilateral partial nephrectomies or unilateral nephrectomy and contralateral resection provided acceptable oncological and functional outcomes.

Emerging surgical treatments for renal cell carcinoma

Treatment of renal cell carcinoma has evolved considerably over the last few years. While total nephrectomy is necessary at times, nephron-sparing surgery, with a goal of renal function preservation, should always be considered. Although open partial nephrectomy is considered the gold standard approach for nephron-sparing surgery, laparoscopic- or robotic-assisted techniques allow urologists to perform renal surgery less invasively, with excellent long-term oncological outcomes. Cryotherapy and radiofrequency ablation are less invasive management approaches for carefully selected patients with small renal masses. Active surveillance should be considered in elderly or patients who are unfit for surgery. Ultimately, the method chosen for management of a renal mass is an informed decision made by the physician and patient.

Is anatomic complexity associated with renal tumor growth kinetics under active surveillance?

INTRODUCTION

Linear growth rate (LGR) is the most commonly employed trigger for definitive intervention in patients with renal masses managed with an initial period of active surveillance (AS). Using our institutional cohort, we explored the association between tumor anatomic complexity at presentation and LGR in patients managed with AS.

METHODS AND MATERIALS

Enhancing renal masses managed expectantly for at least 6 months were included for analysis. The association between Nephrometry Score and LGR was assessed using generalized estimating equations, adjusting for the age, Charlson score, race, sex, and initial tumor size.

RESULTS

Overall, 346 patients (401 masses) met the inclusion criteria (18% ≥ cT1b), with a median follow-up of 37 months (range: 6-169). Of these, 44% patients showed progression to definitive intervention with a median duration of 27 months (range: 6-130). On comparing patients managed expectantly to those requiring intervention, no difference was seen in median tumor size at presentation (2.2 vs. 2.2 cm), whereas significant differences in median age (74 vs. 65 y, P < 0.001), Charlson comorbidity score (3 vs. 2, P<0.001), and average LGR (0.23 vs. 0.49 cm/y, P < 0.001) were observed between groups. Following adjustment, for each 1-point increase in Nephrometry Score sum, the average tumor LGR increased by 0.037 cm/y (P = 0.002). Of the entire cohort, 6 patients (1.7%) showed progression to metastatic disease.

CONCLUSIONS

The demonstrated association between anatomic tumor complexity at presentation and renal masses of LGR of clinical stage 1 under AS may afford a clinically useful cue to tailor individual patient radiographic surveillance schedules and warrants further evaluation.

Heterogeneity and renal mass biopsy: a review of its role and reliability

Increased abdominal imaging has led to an increase in the detection of the incidental small renal mass (SRM). With increasing recognition that the malignant potential of SRMs is heterogeneous, ranging from benign (15%-20%) to aggressive (20%), enthusiasm for more conservative management strategies in the elderly and infirmed, such as active surveillance (AS), have grown considerably. As the management of the SRM evolves to incorporate ablative techniques and AS for low risk disease, the role of renal mass biopsy (RMB) to help guide individualized therapy is evolving. Historically, the role of RMB was limited to the evaluation of suspected metastatic disease, renal abscess, or lymphoma. However, in the contemporary era, the role of biopsy has grown, most notably to identify patients who harbor benign lesions and for whom treatment, particularly the elderly or frail, may be avoided. When performing a RMB to guide initial clinical decision making for small, localized tumors, the most relevant questions are often relegated to proof of malignancy and documentation (if possible) of grade. However, significant intratumoral heterogeneity has been identified in clear cell renal cell carcinoma (ccRCC) that may lead to an underestimation of the genetic complexity of a tumor when single-biopsy procedures are used. Heterogeneous genomic landscapes and branched parallel evolution of ccRCCs with spatially separated subclones creates an illusion of clonal dominance when assessed by single biopsies and raises important questions regarding how tumors can be optimally sampled and whether future evolutionary tumor branches might be predictable and ultimately targetable. This work raises profound questions concerning the genetic landscape of cancer and how tumor heterogeneity may affect, and possibly confound, targeted diagnostic and therapeutic interventions. In this review, we discuss the current role of RMB, the implications of tumor heterogeneity on diagnostic accuracy, and highlight promising future directions.

Coexisting papillary and clear renal cell carcinoma in the same kidney

Renal cell carcinoma (RCC) is the most common solid lesion of the kidney. Bilateral synchronous benign and malignant renal tumors have been defined in some reports. However, unilateral concordance of malignant renal tumors is very rare and there are only a few cases that had synchronous different subtypes of malignant renal tumors arising within the same kidney. Herein, we describe a 67-year-old male patient who had clear cell RCC and papillary RCC in his right kidney that were successfully treated with radical nephrectomy. We also reviewed the pertinent literature.

Pathological concordance and surgical outcomes of sporadic synchronous unilateral multifocal renal masses treated with partial nephrectomy

PURPOSE

Patients with unilateral synchronous multifocal renal masses represent a unique population with renal cell carcinoma. While pathological concordance rates have been studied for bilateral cases, limited data exist on unilateral multifocal disease. We characterized pathological concordance rates in this population and evaluated the outcomes of nephron preservation.

MATERIALS AND METHODS

Patients who underwent surgery from 2000 to 2012 for unilateral synchronous multifocal renal masses were identified from a prospectively maintained database. Demographic, surgical and pathological outcomes of this cohort were analyzed. Malignant concordance rates were defined as agreement of all malignant tumor types in a single renal unit. Histological concordance was defined as agreement of all resected mass histologies, eg all clear cell carcinomas. Nuclear grade was considered concordant if all tumors excised were low (Fuhrman 1 or 2, type 1) or high (Fuhrman 3 or 4, type 2) grade.

RESULTS

Using our institutional database of 2,569 patients with renal tumors we identified 97 with unilateral synchronous multifocal renal masses. Malignant and benign concordance rates were 77.2% and 48.6%, and histological and grade concordance rates were 58.8% and 51.5%, respectively. In this cohort we identified 76 patients (76.3% male) with a median age of 62.5 years who had a total of 241 unilateral synchronous multifocal renal masses and underwent nephron sparing surgery. Median mass size was 2.0 cm (IQR 1.1-3.1), there was a median of 3 tumors per patient and median followup was 24 months (IQR 13-40). Identified renal cell carcinoma histologies included clear cell in 49.4% of cases, papillary in 33.5%, mixed in 4.5% and chromophobe in 2.8%.

CONCLUSIONS

In what is to our knowledge the largest published report of unilateral synchronous multifocal renal masses we document low pathological concordance rates. As such, percutaneous biopsy of a single renal mass in these patients may not help inform treatment decisions. Nephron sparing surgery may be performed with acceptable oncological and functional results in patients with unilateral synchronous multifocal renal masses.

Simultaneous bilateral single-port radical nephrectomies

The management of bilateral enhancing renal masses can be technically challenging. Simultaneous bilateral laparoscopic nephrectomies in postrenal transplant patients have been previously described, but these typically require multiple port placements in addition to a hand port. Herein, we describe simultaneous bilateral single-port laparoscopic radical nephrectomies in a postrenal transplant patient.

Active surveillance: a potential strategy for select patients with small renal masses

Increased abdominal imaging has led to the significant incidental detection of clinically localized renal masses. While the gold standard remains surgical excision, mortality rates from kidney cancer remain relatively unchanged implying that a proportion of small renal masses may be indolent tumors that do not require surgical intervention. As a result, active surveillance has emerged as an alternative management strategy in select patients with significant competing risks. Although the contemporary literature characterizing the natural history of untreated small renal masses is limited, recent data demonstrate that many incidental renal masses demonstrate slow growth kinetics with a low rate of progression to metastatic disease over an intermediate time period. Prospective trials are necessary to define entry and intervention criteria for active surveillance protocols.

Bilateral synchronous sporadic renal tumors: pathologic concordance and clinical implications

OBJECTIVE

To determine the pathologic concordance rates in patients with bilateral synchronous sporadic renal tumors (BSSRT) and to determine factors predictive of concordance.

METHODS

A retrospective chart review from 1985 to 2008 was completed with search criteria of all patients diagnosed with bilateral renal tumors. We included patients who had image-documented BSSRT or via reported history. We excluded patients with bilateral metachronous renal tumors, cystic renal masses, familial renal cell carcinoma (RCC) syndromes, urothelial cell carcinomas, and other variant histology. Univariate and multivariate analysis were conducted to assess for factors predictive of concordance.

RESULTS

We identified 297 patients eligible for analysis. RCC concordance was exhibited in 222 of 249 (89%) of patients. Benign tumor concordance, specifically oncocytoma, was found in 41 of 59 (71%) of patients. Factors such as age, gender, and tumor size on imaging did not have an association with concordance rates for bilateral RCC or bilateral oncocytoma. On multivariate analysis, multifocal tumors were associated with benign concordance (OR = 6.9, 95% CI = 1.6-29.2, P = .009).

CONCLUSION

Malignant and benign concordance rates are high for patients with BSSRT. Given the high concordance of RCC, the data support a management approach consisting of bilateral nephron-sparing surgery whenever possible. However, given the high concordance rate of oncocytoma in this population as well, less aggressive management (renal mass biopsy and surveillance) of the contralateral kidney may be considered after histologic confirmation of one side.

The impact of germline BHD mutation on histological concordance and clinical treatment of patients with bilateral renal masses and known unilateral oncocytoma

PURPOSE

Managing oncocytoma in the setting of bilateral renal masses is a challenging scenario. Nevertheless, to our knowledge the pathological concordance of an oncocytic neoplasm in 1 kidney with tumors in the contralateral kidney is not known. We evaluated the influence of germline Birt-Hogg-Dubé mutation on concordance rates to assist in managing these cases.

MATERIALS AND METHODS

We reviewed the records of patients at the National Institutes of Health between 1983 and 2009 who had bilateral renal masses, known pathology bilaterally and oncocytoma or an oncocytic neoplasm in at least 1 kidney. Oncocytoma or an oncocytic neoplasm in 2 renal units was considered concordant. Demographic, pathological and clinical data were collected.

RESULTS

The population consisted of 40 patients, including 23 with and 17 without a diagnosis of Birt-Hogg-Dubé syndrome. Patients with the syndrome were younger (p <0.01) but there were no other differences between the 2 groups. However, patients with the syndrome had statistically lower histological concordance between bilateral masses than patients without the diagnosis (Fisher's exact test p <0.01). Also, the 8 patients without Birt-Hogg-Dubé syndrome who had multifocal renal masses showed 100% oncocytoma concordance between renal units.

CONCLUSIONS

Of patients with bilateral renal masses those with Birt-Hogg-Dubé syndrome have significantly lower histological concordance than those without the syndrome. Patients with Birt-Hogg-Dubé syndrome should be monitored and treated differently than those without detected genetic mutations, especially patients with multifocal oncocytomas. Genetic testing for Birt-Hogg-Dubé should be considered in the treatment algorithm of patients with bilateral renal masses and known oncocytoma.