Magnetic resonance imaging in the diagnosis and staging of renal masses: a critical appraisal and comparison with computed tomography

Summary The purpose of this prospective study was to compare the accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis and staging of renal masses. MRI was performed with an 0.5 T superconducting MR-scanner using conventional T1- and T2-weighted spin-echo pulse sequences. The results of MRI and CT were compared in 31 patients with a renal mass. In the diagnosis of benign tumors, similar information was obtained by MRI and CT. Regarding malignant tumors, one transitional cell carcinoma, imaged by CT, was not shown by MRI. CT appeared to be slightly more accurate in the determination of perinephric extension of renal cell carcinoma (stage I vs stage II). Similar results were obtained in stage III and stage IV tumors. The main diagnostic limitations which may lead to inaccurate staging of renal cell carcinoma are encountered in MRI as well as CT. They are: the assessment of tumor extension into the intrarenal vein, the differentiation between lymphadenopathy due to reactive hyperplasia and metastatic involvement and the differentiation between tumor extension into adjacent organs and adhesions without tumor spread outside the renal capsule. It is concluded that CT remains the method of choice in the diagnosis and staging of renal masses as long as no substantial improvements in MRI performance have been achieved.     

Complex renal cystic masses: current standards and controversies

Bosniak classification system is the only preoperative diagnostic tool that has proven its efficiency in the management of complex renal cystic masses. However, it is reader dependent, despite its clear definition of each category. The overall incidence of malignancy in each category did not change significantly over the past 20 years. Current limitations are interobserver variability among readers and a fact that a significant proportion of Bosniak III masses have benign character. The goal is to depict these masses preoperatively and spare the patients of unnecessary surgeries, which raises the question: What particular findings will help in differentiating a Bosniak IIF lesion from a Bosniak III lesion? Do we need to define critical variables that could improve accuracy of Bosniak classification by developing a future nomogram or risk calculator? Some radiologists and urologists erroneously tend to group Bosniak II and IIF in one category and observe them regularly. It seems that radiographic growth itself is insufficient factor for intervention. The change of internal architecture and presence of enhancement play the most important role in depicting malignant lesions during the time frame of active surveillance.     

BosniakⅡ~Ⅳ级肾囊性占位临床与病理学特点分析简

目的 探讨Bosniak Ⅱ-Ⅳ级肾囊性占位临床与病理学特点。方法 回顾性分析上海交通大学医学院附属仁济医院从2008年1月至2012年12月CT诊断为囊性肾脏占位（BosniakⅡ、ⅡF、Ⅲ、Ⅳ）的170例患者的病例资料,其中Ⅱ级囊肿73例,ⅡF级囊肿34例、Ⅲ级囊肿38例、Ⅳ级囊肿25例。男105例,女65例;年龄20-85岁,平均（56±14.2）岁;病灶位于左侧87例,右侧66例,双侧17例。80例接受手术治疗的患者中,Ⅱ级囊肿18例,ⅡF级囊肿8例,Ⅲ级囊肿30例,Ⅳ级囊肿24例;行腹腔镜肾囊肿去顶减压术25例,腹腔镜肾部分切除术15例,腹腔镜根治性肾切除术7例,开放肾癌根治术6例,开放肾部分切除术27例。其余90例进行了影像学的随访。分析不同分型囊性肾脏占位的良恶性比例、病理学特点、随访结果。结果 手术病例中Ⅱ级囊肿恶性病例为1例（5.6%）,ⅡF级1例（12.5%）,Ⅲ级16例（53.3%）,Ⅳ级21例（87.5%）,组间比较有明显统计学差异（P＜001）。术后病理结果：恶性肿瘤共39例（透明细胞癌31例,乳头状癌8例）,Fuhrman分级均为Ⅰ级。良性病例共41例（单纯囊肿26例,囊肿伴出血3例,囊肿伴感染5例,囊性肾瘤4例,错构瘤3例）。术后患者随访时间为6-65月,平均随访25月,恶性病例均无发生局部复发或远处转移。影像学随访病例中BosniakⅡ级为55例,ⅡF级26例, Ⅲ级为8例,Ⅳ级为1例,随访时间为6-64月,其中1例Ⅱ级（1.8%）进展至ⅡF级,其余病例均未进展。结论 Ⅱ、ⅡF级囊肿恶性率较低、进展缓慢建议定期随访,而Ⅲ、Ⅳ级恶性率较高应积极手术处理。但由于囊性肾癌组织学分级往往较低,其术后复发、进展及远处转移率较低,保肾手术是首选的治疗方案。     

Comparación entre tomografía computarizada y resonancia magnética en la evaluación de quistes renales complejos empleando la clasificación de Bosniak

Introduction and objectivesThe Bosniak classification of cystic renal lesions was first published in 1986 based on computed tomography (CT). In the present study, we aimed to investigate the effect of magnetic resonance imaging (MRI) on Bosniak category compared with CT, and to determine how this effect changed the treatment modality in the evaluation of complex renal cysts.Material and methodsData of 144 patients were collected retrospectively. After exclusion criteria, 102 cystic renal lesions with a Bosniak category of at least IIF on CT or MRI between 2013 and 2016 were evaluated by 2 abdominal radiologists. The demographic data, Bosniak category, interobserver agreement, and pathologic data of patients who underwent surgery were recorded.ResultsThe coherence between MRI and CT was 75.5%. The Bosniak classification of 17 patients was upgraded with MRI, and the treatment modality changed in 10 patients, and they underwent surgery. The Bosniak category was downgraded from III to IIF in 6 patients out of 8 whose Bosniak category was downgraded with MRI and the treatment modality changed. Surgery was performed in one patient out of these 6 patients, and the pathology was reported as benign. Progression was detected in the follow-up at month 18 of 1 patient out of 5, and surgery was performed. The pathology was reported as renal cell carcinoma. The pathology result was reported as RCC in 35 (68.6%) patients out of 51 who underwent surgery. Progression was detected in 7 patients out of 51 who were followed up (13.7%), and the pathology results were reported as RCC. The majority of the malignant tumors were low stage and grade.ConclusionsMRI may be successfully used in the evaluation of renal cystic lesions. In particular, the challenging Bosniak IIF and all Bosniak III lesions must be evaluated using MRI before making the decision for surgery. The upgrading of Bosniak category with MRI is more possible compared with CT due to its high-contrast resolution, therefore further studies are required to identify whether it was the cause of overtreatment of Bosniak III lesions.     

Extensively Cystic Renal Neoplasms in Adults (Bosniak Classification II or III) – Possible “Common” Histological Diagnoses: Multilocular Cystic Renal Cell Carcinoma,Cystic Nephroma,and Mixed Epithelial and Stromal Tumor of the Kidney

Objective(s): To give an algorithm for resolution of extensively cystic renal neoplasms, preoperatively classified in the Bosniak classification as a category II and III. Methods: From 1991 to 6/2004, 701 patients with 727 renal tumours were surgically treated at our hospital. Extensively cystic tumours were found in 10 cases. Extensively cystic tumours were defined as multicystic tumours without any solid nodules visible neither on CT, nor grossly in the specimen at operation (the Bosniak classification type II or III). Results: Seven multilocular cystic renal cell carcinomas, three mixed epithelial and stromal tumour of the kidney and one cystic nephroma were diagnosed on histology. Conclusion(s): Extensively cystic renal tumours classified as the Bosniak type II or III correspond histologically to the entities mentioned above (multilocular cystic renal cell carcinoma, cystic nephroma, mixed epithelial and stromal tumour of the kidney). These entities cannot be distinguished one from another on preoperative imaging studies. A preoperative biopsy and intra-operative frozen-section analysis do not lead to a correct diagnosis in many cases. Fortunately, the operative strategy is the same for all these tumours. In such cases, the nephron sparing surgery is indicated, whenever technically feasible, as almost all extensively cystic renal tumours have a good prognosis.     

Category migration of renal cystic masses with use of gadolinium-enhanced magnetic resonance imaging

The Bosniak renal cyst classification has been accepted by urologists and radiologists as a way of diagnosing cystic renal masses and determining the management approach. We report two cases of a renal cystic mass that showed a category change from category II on the basis of enhanced computed tomography to category IV after further gadolinium-enhanced magnetic resonance imaging. In both cases, the cysts were later confirmed as kidney cancer by pathology.     

超声造影评估复杂性囊性肾脏肿物的作用

目的：探讨超声造影（CEus）在鉴别囊性肾脏肿物良恶性方面的作用,并评估CEUS在预测恶性囊性肾脏肿物组织学类型方面的作用。方法：回顾性分析2007年1月～2011年12月经常规超声（US）和CEUS检查的43例患者的43个囊性肾性肿物,诊断结果经病理及随访证实。US观察肿瘤的位置、大小、多房或单房、囊壁及分隔最厚处厚度、有无钙化、囊内有无实性结节,实性结节有无彩色血流。CEUS观察病灶的囊壁及分隔增强后厚度、多房或单房、囊壁及囊内容物有无增强、增强程度等。结果：43个病灶中良性13例,恶性30例。恶性肿物中,透明细胞肾癌21例,乳头状肾癌2例,多房囊性肾癌5例,卵巢癌肾转移2例。cEus与US诊断恶性囊性肾脏肿物的ROC曲线下面积分别为0．950、0．806,差异有统计学意义（P=0．034）。多房囊性肾癌与其他亚型囊性肾细胞癌CEUS表现有所不同。多房囊性肾癌多表现为多房囊性肿物,囊内见增强分隔,不伴囊内增强实性结节。其他亚型肾细胞癌多可见囊内增强实性结节。结论：CEUS有助于囊性肾脏肿物良恶性鉴别及恶性囊性肾脏肿物组织学类型的判断。     

Bosniak肾囊性病变分类的临床应用价值

目的 探讨Bosniak分类在肾囊性病变中的临床应用价值.方法 收集2002至2007年手术治疗497例肾囊性病变患者资料.男284例,女213例.平均年龄42岁.病变位于左侧212例,右侧265例,双侧20例.病变直径1.8～11.5 cm,平均5.4 cm.按照Bosniak分类,I类囊肿339例、Ⅱ类49例(其中Ⅱ F 23例)、Ⅲ类44例、Ⅳ类65例.行肾囊肿去顶减压术372例,肾部分切除术51例,根治性肾切除术74例.结果 病理报告为肾恶性肿瘤89例(透明细胞癌74例、乳头状癌12例、低分化癌3例),良性病变408例(单纯囊肿382例、囊肿伴出血6例、囊肿伴感染6例、多房囊性肾瘤5例、纤维囊壁组织9例).I类囊肿中恶性病变3例(O.9%)、Ⅱ类中5例[10.2%,其中非ⅡF为7.7%(2/26),ⅡF为13.O%(3/23)3、Ⅲ类中23例(52.3%)、Ⅳ类中58例(89.2%).组间比较差异有统计学意义(P0.05).403例获随访,随访时间1～5年.75例恶性病变患者中术后1～5年出现肿瘤局部复发和(或)转移9例;328例良性病变中,术后2～5年出现囊肿复发26例.结论 Bosniak分类I类和Ⅱ类肾囊肿一般并不需要积极的外科处理,但ⅡF类囊肿和直径进行性增大以及形态变化明显的囊肿需要引起重视;Ⅲ、Ⅳ类肾囊肿恶变率较高,具备明确手术治疗指征,建议积极处理.     

肾脏小肿块的诊断和治疗（附80例报告）

目的：提高实性或复杂性囊性肾脏小肿块（SRM）的诊断与治疗水平。方法：回顾性分析80例经B超、CT或MRI证实为实性或复杂性囊性SRM患者的临床资料：实性SRM患者75例。BosniakIII级、Ⅳ级囊性SRM患者各3例和2例。良性SRM息者12例,怀疑恶性SRM患者68例。其中行开放根治性肾切除术、腹腔镜根治性肾切除术和开放性保留肾单位手术各52例、5例和11例．对12例良性SRM患者及4例术后病理检查证实为良性者每6～12个月随访1次;对术后病理检查证实为恶性者64例术后每3～6个月密切随访1次。连续3年,以后每年1次。结果：对12例良性SRM患者及4例术后病理检查证实为良性者密切随访未见肿块明显增大、复发或恶变;68例怀疑为恶性SRM患者中,术后病理检查确诊者64例。随访62例无肿瘤复发或转移,1例术后30个月出现肿瘤复发．1例术后16个月死于肿瘤转移。结论：明确SRM的良、恶性,对恶性SRM患者采取合适的治疗方法。仍然是临床处理SRM的关键。     

Multilocular cystic renal cell carcinoma: clinicopathological features and preoperative prediction using multiphase computed tomography

Study Type – Diagnostic (exploratory cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? Multilocular cystic renal cell carcinoma (MCRCC), defined according to the 2004 WHO classification, has good prognosis, which is not affected adversely by large tumour size or advanced stage. Thus nephron‐sparing surgery is proposed when MCRCC is suspected by preoperative radiologic criteria. The present study confirms the low malignant potential of MCRCC. Additionally, the results of the present study provide a simple, useful criteria using a Bosniak classification and Hounsfield unit on multiphase computed tomography images to differentiate MCRCC from other cystic RCC.

OBJECTIVE

? To analyse the clinicopathological and radiological features of multilocular cystic renal cell carcinoma (MCRCC) and to determine the preoperative factors differentiating MCRCC from other cystic RCC (CRCC).

PATIENTS AND METHODS

? The medical records of 53 patients with complex cystic renal masses evaluated by multiphase computed tomography (CT), surgically removed and confirmed as sporadic RCC were reviewed. ? Of these 53 patients, 23 were classified as having MCRCC and 30 as other CRCCs, defined as RCCs with extensive cystic change or cystic necrosis. ? Another 22 patients were treated for complex cystic renal masses presumed to be RCC and diagnosed as having benign cyst.

RESULTS

? Benign cysts and MCRCCs were significantly more likely to be of Bosniak classification III than other CRCCs (77% vs 61% vs 27%, P= 0.001). ? The mean Hounsfield unit (HU) during the corticomedullary phase (CMP) was significantly higher in other CRCCs, with HU ≥38 having 83% sensitivity and 80% specificity for predicting other CRCCs. ? In a multiple regression model, Bosniak classification and mean HU during CMP were independent factors predictive of other CRCCs. ? In the 41 patients with masses >4 cm in diameter, the combination of Bosniak classification IV and HU ≥38 during CMP showed 63% sensitivity, 96% specificity, 91% positive predictive value and 80% negative predictive value, yielding 2% false‐positive and 15% false‐negative rates.

CONCLUSIONS

? The mean HU during CMP and Bosniak classification can differentiate MCRCC from other CRCCs. ? This could help in selecting an appropriate surgical method, such as nephron‐sparing surgery, for complex cystic renal masses >4 cm.     

Treatment of Indinavir sulfate induced urolithiasis in HIV-positive patients

Objectives.To determine the necessity of pelvic computed tomography (CT) in patients of renal cell carcinoma (RCC).Materials and methods. We reviewed the records of 400 patients of RCC, who underwent treatment at our institution between January 1988 and February 2001. These patients were evaluated pre-operatively with ultrasonograms (USG) and contrast enhanced CT scan of the abdomen and pelvis. USG or CT scans of these cases were reviewed for presence of pathology in the pelvis, which were classified into 3 categories viz; benign and likely to be insignificant, benign and likely to be significant; and malignant.Results. Of the 400 cases, 114 were stage I, 68 were stage II, 99 were stage III and 119 were stage IV. In all patients, tumour was identified in the kidney on preoperative CT scan. Fourteen patients (3.5%) had an abnormality on pelvic CT. Five (1.25%) had category 1, three (0.75%) had category 2 and six (1.5%) had category 3 abnormality on pelvic CT. However, all these abnormalities in pelvis were detected prior to CT by other investigations (USG or plain x-ray). Of the six cases with malignant findings, two had superficial bladder cancer, one had RCC in a pelvic kidney and three had bone metastases in the pelvis. Conclusions. Pelvic CT doesnot offer additional information in the vast majority of cases with RCC and should be performed selectively. Thus the cost of diagnostic imaging in RCC can be reduced.     

Mixed epithelial and stromal tumour of the kidney: imaging features

Study Type – Diagnosis (case series)
Level of Evidence 4

OBJECTIVE

To describe the features on ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) of mixed epithelial and stromal tumours of the kidney.

PATIENTS AND METHODS

Five women with renal mixed epithelial and stromal tumours (mean age 55.6 years, range 49–59) who had preoperative imaging were retrospectively analysed. Three ultrasonograms, five contrast‐enhanced CT scans, and one contrast‐enhanced MRI examination were available for review. Specific imaging features analysed included lesion size, location, enhancement and cystic composition. The presence of calcification, septation, nodularity and a capsule were also evaluated.

RESULTS

All mixed epithelial and stromal tumours appeared as well‐marginated, multi‐septate cystic masses with a nodular component. All lesions were classified as Bosniak category III (three) or IV (two). The presence of calcification (four) or a capsule (three) was variable. Two tumours invaginated into the renal pelvis with no invasion.

CONCLUSION

Mixed epithelial and stromal tumours of the kidney have a diverse radiographic appearance, indistinguishable from multilocular cystic nephroma and cystic renal cell carcinoma.     

Contrast-enhanced ultrasound assessment of complex cystic lesions in renal transplant recipients with acquired cystic kidney disease: preliminary experience

We prospectively studied the potential value of contrast-enhanced ultrasound (CEUS) to characterize complex acquired cystic kidney disease (ACKD) or suspected solid renal masses, avoiding the risk of inducing acute kidney injury in 138 renal transplant recipients by contrast-enhanced computed tomography (CT). Forty-three cases (31%) had ACKD; 15 ACKD patients (35%) showed suspicious or nondiagnostic ultrasound. The latter subgroup underwent CEUS and, if the suspicion was confirmed, a contrast-enhanced CT. Thirty five lesions were identified in the 15 patients studied by CEUS. According to the Bosniak classification, 27 cysts were type I (BI), four type II (BII), two type III (BIII) with enhancement at the level of thickened septa; we also identified two solid enhancing lesions (BIV). We followed the BI and BII lesions with serial CEUS, while the remaining four cases underwent contrast-enhanced CT showing two solid lesions and two complex cysts with contrast enhancement in the septea. The four patients underwent surgical resection yielding three renal cell carcinomas one papillary carcinoma as the pathological findings. This preliminary study characterized solid nodules and BIII lesions for further evaluation by CT. CEUS seems to correctly characterize BI and BII cysts that are not clearly defined by standard ultrasound.     

Malignant B-cell lymphoma in renal cyst wall

Renal cysts are frequently found in adults older than 50 years of age. Bosniak type III and IV cysts are commonly associated with malignancy, but most Bosniak I and II lesions are benign, and the optimal management has not been clearly defined. Although computed tomography and ultrasound examinations have improved diagnostic accuracy, some masses will remain indeterminate and require more invasive evaluation. We report a patient with a Bosniak type II renal cyst associated with malignant B-cell lymphoma in the cyst wall diagnosed after laparoscopic renal exploration.     

Laparoscopic evaluation of indeterminate renal cysts: long-term follow-up

PURPOSE: We present our long-term follow-up of patients who have undergone laparoscopic evaluation for their indeterminate renal cysts, specifically reporting those patients who were found to have cystic renal-cell carcinoma (RCC) and assessing the safety and efficacy of the procedure. PATIENTS AND METHODS: Fifty-seven patients with indeterminate renal cysts (28 Bosniak category II and 29 Bosniak category III) underwent laparoscopic evaluation between July 1993 and July 2000. A transperitoneal laparoscopic localization and aspiration of the cyst, cytologic analysis, and biopsy of the cyst wall and base were performed. A total of 11 patients were found to have cystic RCC. Patients with malignancy have been followed for a mean of 40 months (range 6-70 months), and five patients had 5 years or more of follow-up. RESULTS: Eleven patients (19% of the total) were found to have cystic RCC. Three of these patients had Bosniak category II cysts, and eight had category III cysts. All tumors were low grade (I or II), and the stages were T1-2, Nx-0, M0. There has been no evidence of laparoscopic port site or renal fossa tumor recurrence, local recurrence, or metastatic disease to date in these patients. There is no cancer-specific mortality. CONCLUSIONS: Long-term follow-up indicates that laparoscopic evaluation of indeterminate renal cysts is not associated with an increased risk of port site or retroperitoneal or peritoneal recurrence of RCC. It may save a patient from undergoing open surgery and should be considered as a diagnostic option for patients with indeterminate renal cysts.     

Cystic renal cell carcinoma

Cystic renal cell carcinoma includes any malignant neoplasm of renal tubular epithelium which presents as a fluid-filled mass. Approximately 15 per cent of cases of renal cell carcinoma will be cystic on radiologic and pathologic examination. The clinical features of cystic renal cell carcinoma are similar to those which are solid. The radiographic and pathologic findings of cystic renal cell carcinoma are often more confusing and less specific than the findings of renal cell carcinoma which are predominantly solid. There are four basic pathologic mechanisms resulting in cystic renal cell carcinoma: intrinsic multiloculated growth; intrinsic unilocular growth (cystadenocarcinoma); cystic necrosis; and origin from the epithelial lining of a preexisting simple cyst. There are three basic radiologic patterns of cystic renal cell carcinoma: unilocular cystic mass, multiloculated cystic mass, and discrete mural nodule in a cystic mass. Cystic renal cell carcinoma is often extremely difficult to differentiate from non-neoplastic, benign neoplastic, and other malignant neoplastic masses utilizing radiologic studies alone. This review presents the clinical, pathologic, and radiographic features of cystic renal cell carcinoma and discusses its radiologic differential diagnosis.     

Magnetic resonance imaging as an adjunct diagnostic tool in computed tomography defined Bosniak IIF–III renal cysts: a multicenter study

Introduction

CT imaging is the standard examination for renal cystic lesions and defines the Bosniak category, which dictates further management. Given that Bosniak II/IIF/III renal cystic lesions can potentially harbor renal cell carcinoma (RCC), additional diagnostic modalities may be required in management decision making.

Aim

To determine the value of additional magnetic resonance imaging in CT-defined Bosniak IIF–III renal cystic lesions.

Materials and methods

This a multicenter retrospective study of 46 consecutive patients, diagnosed with cystic renal lesions between 2009 and 2016. The inclusion criteria were: (1) cystic renal lesion classified as Bosniak IIF–III on CT, (2) a subsequent MRI examination, and (3) documented outcome via surgery for cystic renal mass or follow-up.

Results

46 patients (35 males, 11 females) were included. The mean size of the cystic lesion was 3.92 cm (0.7–10 cm). According to the CT findings, Bosniak IIF and III were found in 12 (26.1%) and 34 (73.9%) cases. Reclassification of Bosniak category was done after MRI examination in 31 cases (67.4%). An upgrade rate of 58.7% (27 cases) to a higher category was made, while the downgrade rate to a lower category was achieved in 4 cases (8.7%). As a result, significant therapeutic management change was made in 12/31 patients (38.7%), of whom 8 underwent subsequent surgery.

Conclusion

MRI study may reduce the use of Bosniak IIF category (in comparison with CT), which has a direct impact on therapeutic management (surgery vs. surveillance) in a significant proportion of patients.

     

Small renal masses: the value of contrast-enhanced colour Doppler imaging

OBJECTIVE: To assess the value of a microbubble-based ultrasonographic contrast agent for enhancing blood vessels in colour Doppler imaging (CDI) of small renal masses. PATIENTS AND METHODS: Fifty-one patients with small renal masses (< 3 cm in diameter) had prospective CDI before and after intravenous administration of the contrast agent Levovist (Schering, Berlin, Germany). The degree of tumour vascularity was subjectively graded from 0 to IV (indicating an increasing vessel count). Furthermore, peak systolic velocity (PSV), resistive index, and pulsatility index were measured. The CDI findings were then compared with those obtained at histopathological examination. RESULTS: Intra- and/or peritumoral vessels were detected in 26 lesions (51%) by unenhanced CDI and in 48 by enhanced CDI (94%; P = 0.006, McNemar test). Higher grades of tumour vascularity (grade III and IV) were more common in malignant renal masses (P < 0.01). There were PSVs of >80 cm/s only in malignant lesions. Based on receiver operating characteristic analysis, enhanced CDI (area under the curve 0.789) was more accurate than unenhanced CDI (0.576) for differentiating benign from malignant renal masses (P < 0.004). CONCLUSION: Enhanced CDI is better than unenhanced CDI for detecting tumour vascularity, and for discriminating between benign and malignant small renal masses.     

Evaluation of anatomic and morphologic nomogram to predict malignant and high-grade disease in a cohort of patients with small renal masses

ObjectiveTo evaluate a nomogram using the RENAL Nephrometry Score (RENAL-NS) that was developed to characterize masses as benign vs. malignant and high vs. low grade in our patients with small renal masses treated with partial nephrectomy (PN). The nomogram was previously developed and validated in patients with widely variable tumor sizes.Materials and methodsRetrospective review of PN performed between 1/2003 and 7/2011. Imaging was reviewed by a urologic surgeon for RENAL-NS. Final pathology was used to classify tumors as benign or malignant and low (I/II) or high (III/IV) Fuhrman grade. Patient age, gender, and RENAL score were entered into the nomogram described by Kutikov et al. to determine probabilities of cancer and high-grade disease. Area under the curve was determined to assess agreement between observed and expected outcomes for prediction of benign vs. malignant disease and for prediction of high- vs. low-grade or benign disease.ResultsA total of 250 patients with 252 masses underwent PN during the study period; 179/250 (71.6%) had preoperative imaging available. RENAL-NS was assigned to 181 masses. Twenty-two percent of tumors were benign. Eighteen percent of tumors were high grade. Area under the curve was 0.648 for predicting benign vs. malignant disease and 0.955 for predicting low-grade or benign vs. high-grade disease.ConclusionsThe RENAL-NS score nomogram by Kutikov does not discriminate well between benign and malignant disease for small renal masses. The nomogram may potentially be useful in identifying high-grade tumors. Further validation is required where the nomogram probability and final pathologic specimen are available.     

Laparoscopic partial nephrectomy for cystic masses

PURPOSE: Although laparoscopic partial nephrectomy (LPN) has emerged as an effective treatment option in select patients with a solid renal tumor, scant data are available on cystic renal tumors. We report our experience with LPN in 50 patients with a cystic renal lesion. MATERIALS AND METHODS: Of 284 patients undergoing LPN at our institution since August 1999 preoperative computerized tomography identified a suspicious cystic lesion in 50 (17.6%) (group 1). Data were retrospectively compared with those on 50 matched, consecutive patients undergoing LPN for a solid renal mass (group 2). All patients with Bosniak II/IIF cysts were advised to undergo watchful waiting. Surgery was offered if the cyst changed in character or if that was the patient preference. RESULTS: Median tumor size was 3 cm in group 1 and 2.6 cm in group 2 (p = 0.07). Groups 1 and 2 were comparable in regard to perioperative parameters. In patients with Bosniak II (9), IIF (4), III (12) and IV (21) cysts final histopathology revealed renal cell carcinoma in 22%, 25%, 50% and 90%, respectively. All 100 patients had a negative surgical margin. No patient in group 1 had intraoperative puncture/spillage of the cystic tumor. In group 1 during a mean followup of 14 months (range 1 month to 3 years) 1 patient had retroperitoneal recurrence at 1 year despite negative surgical margins during initial LPN. CONCLUSIONS: Surgical outcomes of LPN for suspicious cystic masses are similar to those of LPN for solid tumors. However, extreme caution and refined laparoscopic technique must be exercised to avoid cyst rupture and local spillage.