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Objective: To compare the feasibility and outcomes of renal mass biopsies (RMB) of anatomically complex vs non-complex renal masses., Methods: Our institutional renal tumor database was queried for patients who underwent RMB between 2005 and 2019 and with available nephrometry score. Complex masses were: (1) small (<2 cm), (2) entirely endophytic (nephrometry E=3), (3) hilar (h) or (4) partially endophytic (E=2) and anterior. Demographic and pathologic data were compared. Biopsies were deemed adequate if they resulted in a diagnosis. Concordance with surgical pathology was assessed. These were both presented using proportions. Factors associated with biopsy outcomes were identified using multivariable logistic regression. RMB sensitivity and specificity were calculated using contingency methods., Results: A total of 306 RBMs were included, 179 complex and 127 non-complex. A total of 199 (65%) had an extirpative procedure. Complex lesions were less likely to have an adequate biopsy (89% vs 96%, P = .03), and to be concordant with final surgical pathology from an oncologic standpoint (89% vs 97%, P = .03). There was no significant difference in concordance of histology (76% vs 86%, P = .10) or grade (48 vs 51%, P = .66). On multivariable analyses, only male gender was associated with biopsy adequacy (OR 3.31, 95% CI 1.28-8.55, P = .01). Our overall sensitivity was 93%, specificity 93%, and accuracy 93%. There were no significant differences over time in biopsy outcomes during the study period., Conclusion: RMB of complex lesions is associated with excellent diagnostic yield, albeit lower than non-complex lesions. RMB should not be deferred in cases of anatomically complex lesions where additional data could improve clinical decision-making., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: The natural history of nonclear cell renal cell carcinoma following surgery with curative intent remains poorly defined with postoperative surveillance informed by guidelines largely intended for clear cell renal cell carcinoma. We evaluated relapse patterns and potential implications for post-nephrectomy surveillance in patients with nonclear cell renal cell carcinoma enrolled in the E2805 trial, the largest randomized trial of adjuvant antiangiogenic therapy of high risk renal cell carcinoma., Materials and Methods: We retrospectively analyzed the records of patients with completely resected nonclear cell renal cell carcinoma. Participants received up to 54 weeks of postoperative therapy with sunitinib, sorafenib or placebo and underwent surveillance imaging at standardized intervals for 10 years. For recurrence rates by site the cumulative incidence was estimated, accounting for competing risks. The adequacy of strict adherence to post-nephrectomy surveillance guidelines was evaluated., Results: A total of 403 patients with nonclear cell renal cell carcinoma were enrolled in the study. During a median followup of 6.2 years 36% of nonclear cell renal cell carcinomas recurred. Five-year recurrence rates were comparable for nonclear and clear cell renal cell carcinoma in the 1,541 patients, including 34.6% (95% CI 29.8-39.4) and 39.5% (95% CI 36.9-42.1), respectively. However, patients with nonclear cell renal cell carcinoma were significantly more likely to have abdominal sites of relapse (5-year recurrence rate 26.4% vs 18.2%, p = 0.0008) and significantly less likely to experience relapse in the chest (5-year recurrence rate 13.7% vs 20.9%, p = 0.0005). Current surveillance guidelines would potentially capture approximately 90% of relapses at any site., Conclusions: Nonclear cell renal cell carcinoma may show a distinct pattern of relapse compared to clear cell renal cell carcinoma. Our findings emphasize the importance of cross-sectional, long-term imaging in patients with high risk, resected, nonclear cell renal cell carcinoma.

Objective: To externally validate the Spectrum Score (SS) using a modified calculation based on functional parenchymal volumes (FPVs) instead of renal scans. The SS quantifies acute ischemic injury in the ipsilateral kidney after partial nephrectomy. However, this metric requires renal split function assessment via renal scans, which may be unavailable in routine practice., Methods: We retrospectively reviewed patients with a solitary renal mass and contralateral kidney who underwent partial nephrectomy at our institution between 2015 and 2017. FPVs were calculated using cylindrical volume approximation and used to quantitate relative renal function. Based on renal split function and parenchyma preserved, we determined creatinine ideal , assuming no ipsilateral kidney ischemic injury, and creatinine worst-case , assuming temporary ipsilateral kidney nonfunction. FPV-based SS was defined as follows: (observed peak creatinine-creatinine ideal )/(creatinine worst-case -creatinine ideal ). Functional recovery was defined as follows: (% function saved)/(% parenchyma preserved). Factors associated with FPV-based SS and functional recovery were assessed using linear regression., Results: We assessed 174 patients with a median renal mass size of 2.7 cm (IQR 2.0-3.6), warm ischemia time of 26.0 minutes (IQR 19.0-34.3), and parenchyma preservation of 92.6% (IQR 80.8-100). Preoperative ipsilateral kidney % split function (P = .003), preoperative ipsilateral kidney glomerular filtration rate (P = .045), and warm ischemia time (P = .005) were independently associated with FPV-based SS. Only FPV-based SS (P<.001) was independently associated with functional recovery., Conclusion: The FPV-based SS, which does not require renal scans, quantifies acute ipsilateral renal dysfunction and predicts functional recovery after partial nephrectomy., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: To examine relative contributions of functional parenchymal preservation and renal ischemia following nephron-sparing surgery (NSS). While residual functional parenchymal volume (FPV) is proposed as the key factor in predicting functional outcomes following NSS, efforts to curtail ischemia time continue to add technical complexity to partial nephrectomy., Methods: Our kidney cancer database was queried for patients who underwent NSS with warm ischemia time (WIT). Patients with cross-sectional imaging for FPV calculation were included. Cylindrical volume approximation methodology was used to calculate FPV, accounting for the volume of tumor's endophytic component. Percent estimated glomerular filtration rate (eGFR) preservation, perioperatively and at 6 months, was the outcome metric. Spearman correlation and linear regression analyses were used to evaluate associations of WIT and %FPV preservation with renal function preservation., Results: Of the 179 patients included, median preoperative eGFR was 88.4 (9.5% chronic kidney disease III or IV), tumor size was 2.7 cm (interquartile range [IQR] 2.0-3.6 cm), and R.E.N.A.L. nephrometry was low in 34%, intermediate in 57%, and high in 9%. Median WIT was 30 minutes (IQR 24-36), resulting in 97.4% FPV preservation. Median postoperative eGFR at 6.4 months was 80.5 (19.1% chronic kidney disease III or IV), a median of 93.1% eGFR preservation (IQR 85.1-101.7). At discharge, WIT (P <.001), not %FPV (P = .112), was associated with %eGFR preservation. However, 6 months following surgery, on multivariable analysis, both preoperative eGFR (linear regression coefficient = -0.208, P = .006) and %FPV preservation (linear regression coefficient = 0.491, P = .001), but not WIT (P = .946), demonstrated statistically significant association with %eGFR preservation., Conclusion: Residual FPV, and not WIT, appears to be the main predictor of ultimate renal function following NSS., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: The dire shortage of cadaveric kidneys has led to a gradual expansion of donor criteria in the transplant community. The use of kidneys with anatomical fusion anomalies is uncommon and has not been well defined in the literature. We evaluated the surgical strategies and postoperative outcomes of transplanting cadaveric kidneys with congenital fusion anomalies., Materials and Methods: Three cadaveric kidneys with congenital fusion anomalies were procured and transplanted between May 1994 and November 1999. None of the 3 donors had any significant urological history. All fusion anomalies were identified during the organ procurement process., Results: Anomalies included 1 L-shaped cross-fused ectopic and 2 horseshoe kidneys. All 3 kidneys were procured en bloc. One horseshoe kidney with a narrow isthmus was split and the 2 kidneys were transplanted into separate recipients, while the other horseshoe kidney was transplanted en bloc into a single recipient. The L-shaped kidney was transplanted en bloc into 1 patient. All transplants were successful with a serum creatinine of 1.1 to 1.9 mg/dl., Conclusions: To our knowledge we present the initial case of transplantation of an L-shaped kidney. Cadaveric kidneys with congenital fusion anomalies may be transplanted successfully using various individual technical strategies based on the specific renal anatomy. As such, these kidneys may be used to maximize the increasingly inadequate donor pool.

With increased use of computed tomography (CT) and abdominal ultrasonography, the indications for nephron-sparing surgery are also increasing. Triphasic helical CT and three-dimensional (3D) volume rendering can be combined into a single noninvasive test to delineate renal tumors and normal and complex renal anatomy prior to nephron-sparing surgery. This combination technique has proved accurate and very useful for both preoperative and intraoperative planning by demonstrating renal position, tumor location and depth of tumor extension into the kidney, relationship of the tumor to the collecting system, and renal vascular anatomy. Knowledge of the position of the kidney relative to the lower rib cage, iliac crest, and spine helps in planning the initial surgical incision. By depicting tumor location and depth of extension, helical CT with 3D volume rendering helps ensure complete tumor excision and conservation of adjacent normal renal parenchyma. Depiction of the relationship of the tumor to the collecting system helps anticipate further tumor extension and minimize postoperative complications. Identification of normal renal vasculature and anatomic variants can help minimize ischemic injury and intraoperative bleeding. Radiologists should be familiar with current indications for nephron-sparing surgery and understand what information is required prior to surgery.

The importance of proportioning kidney size to body volume was established by clinical studies which demonstrated that in-born defecits of nephron number predispose the kidney to disease. As the kidney develops, the expanding ureteric bud or renal collecting system induces surrounding metanephric mesenchyme to proliferate and differentiate into nephrons. Thus, it is likely that nephron number is related to ureteric bud growth. The expression patterns of mRNAs encoding Fibroblast Growth Factor-7 (FGF-7) and its high affinity receptor suggested that FGF-7 signaling may play a role in regulating ureteric bud growth. To test this hypothesis we examined kidneys from FGF-7-null and wild-type mice. Results of these studies demonstrate that the developing ureteric bud and mature collecting system of FGF-7-null kidneys is markedly smaller than wild type. Furthermore, morphometric analyses indicate that mature FGF-7-null kidneys have 30+/-6% fewer nephrons than wild-type kidneys. In vitro experiments demonstrate that elevated levels of FGF-7 augment ureteric bud growth and increase the number of nephrons that form in rodent metanephric kidney organ cultures. Collectively, these results demonstrate that FGF-7 levels modulate the extent of ureteric bud growth during development and the number of nephrons that eventually form in the kidney.

Purpose: The purpose of this study was to determine the sensitivity, specificity, and clinical usefulness of renography performed in combination with captopril administration ("captopril renography") in diagnosing renal artery stenosis., Patients and Methods: Fifty-five patients with suspected renal artery stenosis underwent renography prior to performance of renal angiography. Renography was performed on two consecutive days using technetium-99m-diethylenetiamine pentaacetic acid (DTPA) as an index of glomerular filtration rate and iodine-131-orthoiodohippurate (OIH) as an index of renal blood flow. Captopril (25 mg orally, crushed) was administered 1 hour before the second study. Renal artery stenosis was defined as a stenosis exceeding 70%. Renographic criteria were then established, retrospectively, to differentiate renal artery stenosis from essential hypertension based on (1) asymmetry of function and (2) the presence of captopril-induced changes., Results: Renal artery stenosis was detected in 35 of 55 patients (21 with unilateral and 14 with bilateral stenosis). Three criteria were established for diagnosing renal artery stenosis: (1) a percent uptake of DTPA by the affected kidney of less than 40% of the combined bilateral uptake, (2) a delayed time to peak uptake of DTPA, which was more than 5 minutes longer in the affected kidney than in the contralateral kidney, (3) a delayed excretion of DTPA, with retention at 15 minutes, as a fraction of peak activity, more than 20% greater than in the contralateral kidney. The presence of one or more of these criteria was diagnostic of renal artery stenosis, with a sensitivity and specificity of 71% and 75%, respectively before captopril administration, and 94% and 95% after captopril administration. Lesser degrees of asymmetry (i.e., uptake of 40% to 50%) had very poor diagnostic specificity. Among patients with bilateral stenoses, asymmetry identified the more severely affected kidney, but the presence or absence of stenosis in the contralateral kidney could not be reliably determined. When pre- and post-captopril studies were compared, the presence of captopril-induced scintigraphic changes was a highly specific finding for renal artery stenosis, but occurred in only 51% of the cases. OIH scintigraphy provided similar results, with slightly lower sensitivity and specificity., Conclusion: Asymmetry of DTPA uptake, time to peak uptake, or retention seen on a single post-captopril renogram is a highly sensitive and specific finding in detecting renal artery stenosis but does not distinguish unilateral from bilateral disease. If renograms are obtained both before and after captopril administration, the presence of captopril-induced change is a highly specific finding for the detection of renal artery stenosis, but the sensitivity of this finding is low.