Applicability of Bosniak 2019 for renal mass classification on portal venous phase at the era of spectral CT imaging using rapid kV-switching dual-energy CT

OBJECTIVES

To evaluate the applicability of Bosniak 2019 criteria on a monophasic portal venous phase using rapid kilovoltage-switching DECT (rsDECT).

MATERIALS AND METHODS

One hundred twenty-seven renal masses assessed on rsDECT were included, classified according to Bosniak 2019 classification using MRI as the reference standard. Using the portal venous phase, virtual monochromatic images at 40, 50, and 77 keV; virtual unenhanced (VUE) images; and iodine map images were reconstructed. Changes in attenuation values between VUE and 40 keV, 50 keV, and 77 keV measurements were computed and respectively defined as ∆HU40keV, ∆HU50keV, and ∆HU77keV. The values of ∆HU40keV, ∆HU50keV, and ∆HU77keV thresholds providing the optimal diagnostic performance for the detection of internal enhancement were determined using Youden index.

RESULTS

Population study included 25 solid renal masses (25/127, 20%) and 102 cystic renal masses (102/127, 80%). To differentiate solid to cystic masses, the specificity of the predefined 20 HU threshold reached 88% (95%CI: 82, 93) using ∆HU77keV and 21% (95%CI: 15, 28) using ∆HU40keV. The estimated optimal threshold of attenuation change was 19 HU on ∆HU77keV, 69 HU on ∆HU50eV, and 111 HU on ∆HU40eV. The rsDECT classification was highly similar to that of MRI for solid renal masses (23/25, 92%) and for Bosniak 1 masses (62/66, 94%). However, 2 hyperattenuating Bosniak 2 renal masses (2/26, 8%) were classified as solid renal masses on rsDECT.

CONCLUSION

DECT is a promising tool for Bosniak classification particularly to differentiate solid from Bosniak I-II cyst. However, known enhancement thresholds must be adapted especially to the energy level of virtual monochromatic reconstructions.

CLINICAL STATEMENT

DECT is a promising tool for Bosniak classification; however, known enhancement thresholds must be adapted according to the types of reconstructions used and especially to the energy level of virtual monochromatic reconstructions.

KEY POINTS

• To differentiate solid to cystic renal masses, predefined 20 HU threshold had a poor specificity using 40 keV virtual monochromatic images. • Most of Bosniak 1 masses according to MRI were also classified as Bosniak 1 on rapid kV-switching dual-energy CT (rsDECT). • Bosniak 2 hyperattenuating renal cysts mimicked solid lesion on rsDECT.

The efficacy of the new Bosniak classification v.2019 in benign lesions prediction within the higher Bosniak cysts classes

INTRODUCTION

Identification of benign lesions among higher classes of renal Bosniak cysts who are vulnerable to active surveillance instead of surgical approach is still questionable. We aimed in this study to delineate the efficacy of the new Bosniak v2019 classification in benign lesions identification among those cases with higher Bosniak classes in comparison with the final histopathology.

MATERIALS

In a retrospective review between 2010 and 2021 for patients diagnosed as higher classes Bosniak renal masses was done. Patients' demographics and radiological data i.e.,: age, gender, and final Bosniak v2019 categorization for class III: (1) Enhancing thick wall/septa >4 mm (III-WS) and (2) Enhancing irregular wall/septa or convex protrusion with obtuse margins <3 mm (III-OP) and for class IV as: (1) Enhancing nodule or convex protrusion with obtuse margins >4 mm (IV-OP) and (2) Enhancing nodule or convex protrusion with acute margins of any size (IV-AP).

RESULTS

A total of 137 patients were included. Bosniak III was identified in 56 patients. Malignancy was detected in 74.5% of resected masses. Among resected Bosniak III cyst, 46.4% were benign histopathologically. Male gender and Bosniak III-OP were independent risks for malignancy among the resected Bosniak III cysts. Conversely, in resected Bosniak IV renal cysts, only 9 of resected masses were benign. In univariate analysis, male gender, absence of multilocular cyst and endophytic masses were predictors for malignancy in resected Bosniak IV cyst. None of the previous predictors was significant in multivariate analysis.

CONCLUSION

The Bosniak subclassification v.2019 can define benign lesions. Bosniak III-OP was an independent risk for malignancy detection among the resected Bosniak III cysts.

Pathological report and prognostic meaning of Bosniak IV cysts: results from a contemporary cohort

Introduction

Surgery is the recommended treatment for Bosniak IV renal cysts. We performed a retrospective analysis of Bosniak IV lesions surgically removed to increase evidence on their prognostic meaning.

Material and methods

Patients with a Bosniak IV cyst were considered. A contrast-enhanced computed tomography (CT) scan or magnetic resonance imaging (MRI) detected a solid component with contrast enhancement. In no case a percutaneous biopsy was performed. A radical (9, 21.4%) or partial (33, 78.6%) nephrectomy was performed with laparoscopic (14, 33.3%) or robot-assisted (28, 66.7%) approach. Analysis of the final pathology was performed, and recurrence rate was assessed.

Results

42 patients were included. Median lesion size was 54.7 mm (IQR 20.0-81.2). A solid tumour was detected in 40 patients (95.2%), whereas in 2 cases (4.8%) a benign cyst without neoplastic component was diagnosed. Final pathology revealed a low-grade clear cell renal cell carcinoma (ccRCC) in 16 cases (38.0%), a multilocular cystic renal neoplasm of low malignant potential in 6 cases (14.3%), a low-grade papillary RCC (pRCC) type I in 4 cases (9.5%), a clear cell papillary RCC (ccpRCC) in 10 cases (23.8%) and an oncocytoma in 2 cases (4.8%). A high-grade ccRCC was detected in 2 cases (4.8%), whereas no patients had a pRCC type II. In all cases surgical margins were negative. Median follow-up was 24 months and no recurrence occurred.

Conclusions

Our results increase evidence on the favourable pathology and good prognosis of Bosniak IV renal cysts, supporting the role of surgery as a definitive treatment and suggesting the need for a low-intensity follow-up.

Prevalence of malignant or possibly malignant renal masses among homogeneous low-attenuation masses that are too small to characterize at computed tomography

BACKGROUND

Homogeneous low-attenuation renal masses that are too small to characterize (tstc) are considered clinically insignificant; however, based primarily on expert opinion.

OBJECTIVE

To determine the prevalence of malignant or possibly malignant masses among homogeneous low-attenuation renal masses that are tstc.

MATERIALS AND METHODS

This retrospective cross-sectional study evaluated 75 patients with 104 tstc who underwent renal CT and MRI between Jan 2016 and Jul 2022. Low-attenuation renal masses measuring < 1 cm in size were identified and, independently evaluated by two blinded radiologists measuring attenuation (Hounsfield Units, HU) at non-contrast enhanced CT (NECT) and nephrographic phase contrast-enhanced (CE)-CT when possible. Reference standard for benign cyst was MRI and for other renal masses was pathology or MRI showing enhancement.

RESULTS

Average tstc size was 6 ± 2 (range 2-10) mm. Considering only incidental tstc (CT performed for another reason), 100% (98/98, 95%CI 96-100%) tstc were benign. Overall, considering both incidental and tstc referred for further characterization, there were 94% (98/104; 95% Confidence Intervals [CIs] 88-98%) benign cysts and 6% (6/104; 95%CI 2-12%) other masses (1 Bosniak 2F cystic mass, 2 probable renal cell carcinoma (RCC), three metastases). Pseudoenhancement, attenuation change > 10 HU or > 20 HU, was present in 29% (15/59) and 12% (7/59) benign cysts. All six other masses enhanced by > 20 HU. CECT threshold of ≤ 30 HU correctly classified 62% of benign cysts (61/98). All six other masses measured > 30 HU at CECT.

CONCLUSION

The prevalence of malignant or possibly malignant renal masses among homogeneous low-attenuation too small to characterize masses among incidental tstc masses is near zero. Attenuation measurements misclassify a substantial proportion of these cysts, likely due to their small size.

Application of CECT, CEMRI, and contrast-enhanced ultrasonography in the evaluation of renal cystic lesions: a systematic review and meta-analysis of retrospective studies

The purpose of this meta-analysis was to investigate the role and effect of CECT, CEMRI and CEUS in the detection of renal cystic lesions, and to provide evidence-based basis for clinical examination and treatment. The Cochrane Library, EMBASE, and PUBMED databases were searched from January 2012 to December 2022 for article retrieval. The articles on the treatment of cystic renal disease were searched. According to the inclusion criteria, the included articles were evaluated with the Jad scale and Cochrane manual version 5.1, and the included articles was analyzed by Review Manager 5.4.1. A total of ten relevant articles were included in this meta-analysis. The results of this meta-analysis indicated that CEUS had high sensitivity and specificity in diagnosing renal cystic lesions, which was statistically significant.

Cystic Renal Masses: Old and New Paradigms

Cystic renal masses describe a spectrum of lesions with benign and/or malignant features. Cystic renal masses are most often identified incidentally with the Bosniak classification system stratifying their malignant potential. Solid enhancing components most often represent clear cell renal cell carcinoma yet display an indolent natural history relative to pure solid renal masses. This has led to an increased adoption of active surveillance as a management strategy in those who are poor surgical candidates. This article provides a contemporary overview of historical and emerging clinical paradigms in the diagnosis and management of this distinct clinical entity.

Comparison of Bosniak Classification of cystic renal masses version 2019 assessed by CT and MRI

OBJECTIVE

To compare imaging features in cystic masses imaged with both CT and MRI using Bosniak Classification version 2019 (Bosniak.v2019) and original Bosniak Classification (Bosniak.original).

MATERIALS AND METHODS

This IRB-approved, retrospective, cross-sectional study evaluated sixty-five consecutively identified cystic (≤ 25% enhancing) masses imaged by CT and MRI between 2009 and 2019: 35 with histologic diagnosis and 30 Bosniak.v2019 Class 2 and Class 2F cystic masses verified by an expert radiologist (R1) with minimum 5-year stability. Three radiologists (R2, R3, R4) independently evaluated CT, followed by MRI and assigned Bosniak.original and Bosniak.v2019 class in two sessions separated by ≥ 1 month and assessed the following: septa number, septa/wall thickness, and protrusions. Discrepancies were resolved by consensus with R1.

RESULTS

There was 70.8% agreement (kappa = 0.60, p = 0.0146) in class assigned by CT versus MRI for Bosniak.original and 72.3% agreement (kappa = 0.63, p = 0.006) for Bosniak.v2019. Increased septa number (p < 0.001) and more protrusions (p = 0.034) were identified on MRI, with no differences in septal/wall thickness (p = 0.067, 0.855) or protrusion size (p = 0.467). For both CT and MRI, Bosniak.v2019 improved specificity (79.0% [95% confidence interval 71.0-87.0%] CT, 70% [62.0-77.0%] MRI) compared to Bosniak.original (63.0% [56.0-69.0%] CT, 66.0% [58.0-74.0%] MRI) with maintained sensitivity and higher overall accuracy. Inter-observer agreement was similar-to-slightly higher for Bosniak.v2019 (K = 0.44 CT, 0.39 MRI) versus Bosniak.original (K = 0.35 CT, 0.37 MRI).

CONCLUSION

Class assignment differs in cystic masses evaluated by CT versus MRI for original and v2019 Bosniak Classification with similar-to-slightly higher agreement and improved specificity and higher overall accuracy on both CT and MRI with Bosniak version 2019.

Evaluation of Cystic and Solid Renal Lesions with Contrast-Enhanced Ultrasound: A Retrospective Study

Purpose Renal lesions are frequent random findings on CT, MRI, and conventional ultrasound. Since they are usually found accidentally, the respective examinations have not been performed optimally to provide a conclusive diagnosis, making additional multiphase contrast-enhanced examinations necessary. The aim of the study is to correlate CEUS findings with the final diagnosis and to determine whether it is a suitable method for the conclusive characterization of undetermined renal lesions. Materials and Methods All CEUS examinations of focal renal lesions performed at our institute between 2007 and 2014 were retrospectively examined. 437 patients with a total of 491 lesions and 543 examinations were included. 54 patients had bilateral lesions. One patient had three lesions in one kidney. Histology was available in 49 cases and follow-ups in 124 cases. The sensitivity, specificity, positive and negative predictive value as well as positive and negative likelihood ratios were calculated. Results There were 54 malignant and 437 benign lesions. The sensitivity and specificity were 0.981/0.954 overall, 1.000/0.956 for cystic lesions, 0.977/0.906 for solid lesions, and 0.971/0.071 for the histologically confirmed lesions. Bosniak classification was consistent in 289 of 301 lesions (96%). Only 12 lesions (3.9%) were falsely assessed as malignant. Conclusion CEUS is an appropriate method for the clarification of undetermined renal lesions. The characterization of cystic lesions according to Bosniak is adequately possible, especially for potentially malignant lesions (types III and IV).

Multi-disciplinary team conference clarifies bosniak classification of complex renal cysts

OBJECTIVES

The aims of this study are to determine the progression rate of Bosniak IIF cysts, the malignancy rates of complex renal cysts in patients undergoing surgery and explore the influence of multi-disciplinary team conference (MDT) on re-classification of Bosniak cysts.

MATERIALS AND METHODS

All CT scans from January 2010 to 2017 were pooled into a database. Initially, 167 patients were identified with possible Bosniak IIF, III or IV cysts. Patients with follow up of less than 24 months, without progression or regression were excluded.

RESULTS

Thirty-one (18.6%) cysts of the initial 167 cysts were either up or downgraded at a MDT. Twenty-six of the 31 cysts were up or downgraded at the primary MDT, 13 cysts (50%) were downgraded, five cysts (19.2%) were upgraded and eight cysts (30.8%) were re-classified as solid tumors. Of those 19/26 (73.1%) were primary interpreted by a periphery radiologist and re-classified centrally. The last five patients 5/120 cysts (4.2%) were re-classified during follow up. 116 patients with a total of 120 cysts met the inclusion criteria, 79 (65.8%) Bosniak IIF, 28 (23.3%) Bosniak III and 13 (10.8%) Bosniak IV cysts represented. Median follow up of Bosniak IIF cysts were 46 months. One Bosniak IIF cyst progressed to a solid tumor at 15 months from diagnosis, progression rate 1.3%. Histopathology was papillary renal cell carcinoma. Malignancy rates of Bosniak III and IV cysts were 50% and 78%, respectively.

CONCLUSION

Multi-disciplinary team conference may have an important role in correct classification of Bosniak cysts.

TRIAL REGISTRATION

None.

Contrast-enhanced ultrasound (CEUS) of cystic renal lesions in comparison to CT and MRI in a multicenter setting

PURPOSE

Contrast-enhanced-ultrasound (CEUS) has been frequently used in assessment of cystic renal lesions.

OBJECTIVE

The aim of this study was to investigate the Bosniak classification in CEUS compared to CT and MRI in a multi-center setting.

METHODS

Bosniak classification in CEUS examinations of cystic renal lesions were compared to imaging findings in computed-tomography (ceCT) and magnetic-resonance-imaging (ceMRI). Imaging results were correlated to histopathological reports. All examinations were performed by experts (EFSUMB level 3) using up-to-date CEUS examination-protocols.

RESULTS

Overall, 173 cystic renal lesions were compared to subgroups CT (n = 87) and MRI (n = 86). Using Bosniak-classification 64/87 renal cysts (73.6%) were rated equal compared to CT with upgrade of four lesions (4.6%) and downgrade of 19 lesions (21.8%) by CT (Intra-class-correlation [ICC] coefficient of 0.824 [p < 0.001]). CEUS compared to MRI, presenting different scoring especially in classes Bosniak IIF (n = 16/31) and Bosniak III (n = 16/28) with an ICC coefficient of 0.651 (p < 0.001).

CONCLUSION

CEUS can visualize even finest septal and small nodular wall enhancement, which may result in an upgrade of cystic lesions into a higher Bosniak class compared to CT or MRI. Thus, a modification of the Bosniak classification on CEUS may reduce unnecessary biopsies and surgery.

Management of complex renal cysts in Canada: results of a survey study

Background

Bosniak III and IV cysts have a high risk of malignancy and have traditionally been managed surgically. However, growing evidence suggests that many can be managed by active surveillance. The main objective of this study was to characterize the use of surveillance in the management of complex renal cysts.

Methods

A web-based survey was sent to all registered, active members of the Canadian Urological Association (N = 583) in October 2018.

Results

The survey response rate was 24.7%. Management of Bosniak III cysts varied considerably. A large proportion of respondents (33.1%) offered active surveillance in > 50% of cases. Only 13.7% of respondents reported never or rarely (< 5% of cases) offering surveillance. In contrast, for Bosniak IV cysts, 60.1% of urologists never or rarely offered surveillance, while only 10.1% offer it in > 50% of cases. A significantly greater proportion of academic urologists, compared to non-academic urologists, viewed surveillance as a management option for patients with a Bosniak III or IV cyst. The most commonly reported barriers to a greater adoption of surveillance were concerns regarding its oncologic safety, the lack of data to support surveillance in this population, and the lack of triggers for discontinuation of active surveillance and intervention.

Conclusions

Despite active surveillance being included as a management option in guidelines, many Canadian urologists are reluctant to offer surveillance to patients with Bosniak III or IV cysts. Practice patterns are heterogeneous among those offering surveillance. High-quality studies are required to better define the benefits and risks of cystic renal mass surveillance.

Small (< 4 cm) Bosniak renal cysts: association of initial fluid percentage and enhancing solid volume thresholds with future lesion behavior

PURPOSE

Evaluate the fluid percentage (FP) and enhancing solid volume (SV) of small (< 4 cm) Bosniak 2F, 3 and 4 renal lesions and the association with Bosniak category at baseline and follow-up.

METHODS

Hospital database was searched from 1/1/2010 to 8/3/2018 for small (< 4 cm) Bosniak 2F, 3 and 4 lesions studied with initial and follow-up C+CT/MRI. Two radiologists blindly assigned Bosniak categories to first and last available studies. One radiologist performed volumetric analysis of each lesion, calculating the FP and SV. Association with Bosniak category was explored.

RESULTS

121 patients (84:37 M:F) were identified with 136 renal lesions (84, 37 and 15 Bosniak category 2F, 3 and 4) and followed for 1-12.3 years (mean 3.5 years). 87% (73/84) of 2F lesions were downgraded or remained stable. 48% (25/52) of 3/4 lesions were downgraded. Higher FP was associated with a lower Bosniak category (p value = 0.0042). Increase in FP was associated with the probability of being downgraded on follow-up (OR 1.03, p value = 0.0036), while increase in fluid volume of lesion was directly associated with change in overall lesion size among lesions that were downgraded (b-estimate = 0.03, p value = 0.0003). All Bosniak 3/4 lesions with initial SV less than 0.05 cc were downgraded.

CONCLUSION

FP and SV are useful quantitative surrogates for Bosniak category and future behavior, respectively. Growth of small renal lesions by an increase in fluid volume and FP leads to a downgrade in Bosniak category. Initial SV less than 0.05 cc in Bosniak 3/4 lesions suggests possible future downgrade.

CT and MR imaging of cystic renal lesions

Cystic renal lesions are a common incidental finding on routinely imaging examinations. Although a benign simple cyst is usually easy to recognize, the same is not true for complex and multifocal cystic renal lesions, whose differential diagnosis includes both neoplastic and non-neoplastic conditions. In this review, we will show a series of cases in order to provide tips to identify benign cysts and differentiate them from malignant ones.

Endothelin-1 Level in Patients with Simple Renal Cyst

INTRODUCTION

Endothelin-1 (ET-1) is potent vasoconstrictive peptide and elevated ET-1 levels are associated with hypertension, endothelial dysfunction and atherosclerosis. Research on (ET-1) has demonstrated that elevated ET-1 levels in autosomal dominant polycystic kidney disease leads to systemic hypertension. The prevalence of simple renal cysts increases with age and the association with simple renal cyst and hypertension is not clear. The aim of this study was to investigate the ET-1 levels in patients with simple renal cyst and compare them with those in healthy adults.

MATERIALS AND METHODS

The study included patients that underwent laparoscopic renal cyst decortication in the Department of Urology and healthy controls. Serum and urinary ET-1 levels were measured before surgery and one month after it in the patients with simple renal cyst. Serum ET-1 levels were measured in healthy adult patients. Ambulatory blood pressure was measured in all patients. Glomerular filtration rate was measured according to the chronic kidney disease epidemiology collaboration formula.

RESULTS

Thirty-two patients were included in the present study. Of these, 16 patients with simple renal cyst were allocated into group 1 and 16 healthy patients - in group 2. There was no significant difference between systolic and diastolic blood pressure between the groups (.

CONCLUSIONS

The present study demonstrated that serum EL-1 level in patients with simple renal cyst was lower than that in healthy people. Further studies are needed to investigate the EL-1 levels in simple renal cyst patients.

Clear Cell Papillary Renal Cell Carcinoma: A Recent Entity With Distinct Imaging Patterns

OBJECTIVE. Clear cell papillary renal cell carcinoma (RCC), an entity with strikingly indolent behavior, recently was added to the World Health Organization classification of renal tumors and represents the fourth most common histologic type of renal cell carcinoma. This article aims to describe the imaging features of clear cell papillary RCC along with its clinical and pathologic characteristics. MATERIALS AND METHODS. This retrospective study consisted of 27 patients with 44 clear cell papillary RCC tumors. The inclusion criteria were a pathologically proven clear cell papillary RCC and the availability of preoperative imaging including at least CT or MRI. Two experienced radiologists performed the imaging analysis independently. RESULTS. Patients (mean age, 62 years old) presented with renal failure in 26% of cases, and four had a tumor-predisposing disease. Multiple clear cell papillary RCC tumors occurred in 5 of the 27 patients. Two imaging patterns were recognizable. Solid clear cell papillary RCC (n = 23, 52%) presented as heterogeneous tumors with minor cystic changes (74%) and rarely exhibited calcifications (10%). All solid tumors showed hyperintensity on T2-weighted images compared with renal cortex and maximal enhancement on corticomedullary phase with a delayed washout. Cystic clear cell papillary RCC (n = 21, 48%) were classified as Bosniak IV (57%), III (33%), or IIF (10%), with a predominant unilocular pattern (76%). Pathologic stage according to TNM classification was mostly pT1a and low grade on nucleolar grade. All patients were alive at the date of last follow-up after treatment with no metastasis or recurrence. CONCLUSION. Clear cell papillary RCC exhibits two imaging patterns including cystic and solid in almost equal proportion. Imaging characteristics of solid clear cell papillary RCC including high signal T2 intensity and early arterial enhancement are unexpectedly distinct from papillary RCC and very similar to clear cell RCC.

Long-term oncological outcomes of cystic renal cell carcinoma according to the Bosniak classification

OBJECTIVES

To evaluate the prognostic role of the Bosniak classification on the long-term oncological outcomes of cystic renal cell carcinomas.

MATERIAL AND METHOD

In a national multicentric retrospective study, we included patients treated surgically for localized cystic RCC from 2000 to 2010. Patients with a follow-up of less than 4 years, benign tumors, and ablative treatments were excluded. The primary outcome was disease-free survival.

RESULTS

152 patients met the inclusion criteria: Bosniak II (6%), III (53%), IV (41%), with a median follow-up of 61 (12-179) months. Characteristics of the population and the tumors were [median, (min-max)] age 57 (25-84) years old, tumor size 43 mm (20-280), RENAL score 7 (4-12), PADUA score 8 (5-14). Treatments were 55% partial nephrectomy, 45% radical nephrectomy, 74% open surgery, and 26% laparoscopy. In pathological report, cystic RCC were mainly of low grade (1-2, 77%) and low stage (pT1, 81%). The two main histological subtypes were conventional (56%) and papillary (23%) RCC. Staging at presentation and histological characteristics were similar between Bosniak III and IV, except for high grade which was more common in Bosniak IV (12 vs 36%, p < 0.01). The Bosniak classification was not predictive of the recurrence, as 5- and 10-year disease-free survival were similar in Bosniak III and IV (92% vs 92% and 84% vs 83%, p = 0.60).

CONCLUSION

The Bosniak classification is predictive of the risk of malignancy but not of the oncological prognosis. Regardless of the initial Bosniak categories, almost all cystic RCCs were of low stage/grade and had low long-term recurrence rate.

Active Surveillance Versus Nephron-Sparing Surgery for a Bosniak IIF or III Renal Cyst: A Cost-Effectiveness Analysis

OBJECTIVE

The objective of our study was to evaluate the cost-effectiveness of active surveillance (AS) versus nephron-sparing surgery (NSS) in patients with a Bosniak IIF or III renal cyst.

MATERIALS AND METHODS

Markov models were developed to estimate life expectancy and lifetime costs for 60-year-old patients with a Bosniak IIF or III renal cyst (the reference cases) managed by AS versus NSS. The models incorporated the malignancy rates, reclassification rates during follow-up, treatment effectiveness, complications and costs, and short- and long-term outcomes. An incremental cost-effectiveness analysis was performed to identify management preference under an assumed $75,000 per quality-adjusted life-year (QALY) societal willingness-to-pay threshold, using data from studies in the literature and the 2015 Medicare Physician Fee Schedule. The effects of key parameters were addressed in a multiway sensitivity analysis.

RESULTS

The prevalence of malignancy for Bosniak IIF and III renal cysts was 26% (25/96) and 52% (542/1046). Under base case assumptions for Bosniak IIF cysts, the incremental cost-effectiveness ratio of NSS relative to AS was $731,309 per QALY for women, exceeding the assumed societal willingness-to-pay threshold, and AS outperformed NSS for both life expectancy and cost for men. For Bosniak III cysts, AS yielded greater life expectancy (24.8 and 19.4 more days) and lower lifetime costs (cost difference of $12,128 and $11,901) than NSS for men and women, indicating dominance of AS over NSS. Superiority of AS held true in sensitivity analyses for men 46 years old or older and women 57 years old or older even when all parameters were set to favor NSS.

CONCLUSION

AS is more cost-effective than NSS for patients with a Bosniak IIF or III renal cyst.

Collecting duct carcinoma kidney masquerading as hydatid cyst: A rare case report and review of literature

Cystic renal masses pose diagnostic challenge especially when they belong to Bosniak Type II and III. Septal and nodular enhancement on computed tomography (CT) is the strongest predictor of malignant process. A unilocular cyst with a calcified rim or a multilocular cystic lesion with heterogeneity on CT goes in favor of hydatid disease. We report a case in a 65-year-old female who presented with painless hematuria, was found to have a cystic mass in the right kidney. The mass turned out to be collecting duct carcinoma after histopathological examination though imaging studies were in favor of a hydatid cyst.

Cystic Appearance on Imaging Methods (Bosniak III-IV) in Histologically Confirmed Papillary Renal Cell Carcinoma is Mainly Characteristic of Papillary Renal Cell Carcinoma Type 1 and Might Predict a Relatively Indolent Behavior of Papillary Renal Cell Carcinoma

AIM

The aim of this study was to determine the proportion of cystic tumors according to preoperative CT (Bosniak III, IV) among surgically treated patients with histologically confirmed papillary renal cell carcinoma (pRCC) and to assess progression rates among patients with and without cystic appearance on imaging.

METHODS

A total of 138 patients with pRCC histology surgically treated in the period of January 2007-March 2017 were included. Clinical and radiological characteristics, type of surgery, histopathology results, and follow-up data were recorded and statistically evaluated.

RESULTS

Forty-one cases (29.7%) of cystic lesions (10× BIIF, 14× BIII, 17× BIV) were detected by CT. Patients with pRCC1 significantly more frequently presented with cystic appearance on CT (33/78; 42.3%) in comparison to other papillary types (8/60; 13.3%; p = 0.0002). During a median follow-up time of 49.4 months, only 2 patients with cystic lesions progressed after surgery.

CONCLUSIONS

Cystic appearance on imaging methods is mainly a characteristic of pRCC1 (42.3%). Cystic morphology on imaging might predict a relatively indolent behavior of all pRCC types. Preoperative scoring systems including tumor growth patterns (cystic vs. solid) are needed for further classification.

Bosniak category III renal lesions: likelihood of malignancy based on computed tomography findings

Introduction

Bosniak introduced a classification of renal cysts based on imaging characteristics. Cystic renal changes are categorized determining their risk of malignancy and further management. However, defining the malignancy of category III lesions still remains a challenge and our aim was to evaluate the features of malignancy in computed tomography within this category.

Material and methods

The Vilnius University Hospital Santariškių Klinikos information system was retrospectively searched for computed tomography examinations in which Bosniak category III lesions were reported. Data of genetic disorders and history of malignancy were collected. Longest diameter, location, shape, amount and location of calcification, contrast enhancement of Bosniak category III lesions were evaluated. The relation between collected data and malignancy was estimated.

RESULTS

There were 73 patients with Bosniak category III lesions included and 43 cysts were surgically removed and histologically analyzed. Mean tumor size was significantly lower in malignant lesions. Mean enhancement in arterial and portovenous phase, change of mean enhancement in portovenous and native phases were significantly different between benign and malignant lesions. Significant differences in the contrast enhancement pattern was found: septa and capsular enhancement was detected in 28.6% (n = 12) of cases in malignant lesions, while only 4.8% (n = 2) benign lesions show the same enhancement pattern. Some other features showed tendencies to be more prevalent in malignant lesions, however, no significant differences were found.

Conclusions

The collected data and selected features do not allow us to reliably differentiate Bosniak category III cystic lesions as benign or malignant. Some of the criteria showed some tendencies, however, further studies are required to confirm these findings' potential.

Cystic renal masses

PURPOSE

The purpose of the study is to provide an update on the imaging evaluation of cystic renal masses, to review benign and malignant etiologies of cystic renal masses, and to review current controversies and future directions in the management of these lesions.

CONCLUSIONS

Cystic renal masses are relatively common in daily practice. The Bosniak classification is a time-proven method for the imaging classification and management of these lesions. Knowledge of the pathognomonic features of certain benign Bosniak 2F/3 lesions is important to avoid surgery on these lesions (e.g., localized cystic disease, renal abscess). For traditionally surgical Bosniak lesions (Classes 3 and 4), there are evolving data that risk stratification based on patient demographics, imaging size, and appearance may allow for expanded management options including tailored surveillance or ablation, along with the traditional surgical approach.

Outcomes and complications related to the management of Bosniak cystic renal lesions

OBJECTIVE

The objective of our study was to evaluate outcomes and complications related to the management of Bosniak category IIF, III, and IV renal cysts.

MATERIALS AND METHODS

For this multiinstitutional retrospective study, a Web-based Research Electronic Data Capture (REDCap) data registry was used to record data of 286 adult patients with 312 prospectively classified Bosniak IIF, III, and IV renal cysts diagnosed between January 2000 and October 2011. Included patients were managed by surgery (n = 86), percutaneous ablation (n = 19), or imaging surveillance of 1 year or more (n = 181). The median number of years of clinical surveillance was 2.4 years (range, 0-11.7 years), 2.6 years (range, 0.4-11.4 years), and 3.2 years (range, 1.1-11.6 years) for patients managed by surgery, ablation, and imaging surveillance, respectively. Pathologic and survival outcomes and complications related to management were evaluated.

RESULTS

The malignancy rate at surgical pathology was 38% (3/8) for Bosniak IIF, 40% (29/72) for Bosniak III, and 90% (18/20) for Bosniak IV renal cysts. There were no metastases or deaths (0/144) directly related to Bosniak IIF renal cysts. There were no deaths (0/113) directly related to Bosniak III renal cysts, although one patient (1/113) developed local progression and lung metastases after thermal ablation. One patient with a Bosniak IV renal cyst (1/29) presented with and died of metastatic disease. Moderate to severe complications occurred in 19% (16/86), 5% (1/19), and 0% (0/181) of patients managed by surgery, ablation, and imaging surveillance, respectively (p < 0.0001). Severe complications occurred in 7% (6/86) of surgical patients and included multiorgan failure (n = 2), acute myocardial infarction (n = 1), acute ischemic stroke (n = 1), conversion to hemodialysis-dependent chronic kidney disease (n = 1), and postoperative severe hemorrhage (n = 1).

CONCLUSION

There were no deaths from Bosniak IIF or III renal cysts regardless of management approach. Moderate to severe complications are frequent in patients managed by surgery.

Intensity modulated radiotherapy (IMRT) for patients of the Brazilian unified health system (SUS): an analysis of 508 treatments two years after the technique implementation

The Bosniak classification for renal cysts was developed in the late 1980s in an attempt to standardize the description and management of complex cystic renal lesions. Alterations were made to such a classification in the 1990s and, the last one, in 2005. Currently, five categories of cystic renal lesions are defined - namely, I, II, II-F, III and IV –, according to their degree of complexity and likelihood of malignancy. Despite being initially described for computed tomography, this classification has been also utilized with some advantages also for magnetic resonance imaging. The present article reviews the different phases of this classification, its diagnostic efficacy and the most controversial features of its use.

Bosniak classification for complex renal cysts: history and critical analysis

The Bosniak classification for renal cysts was developed in the late 1980s in an attempt to standardize the description and management of complex cystic renal lesions. Alterations were made to such a classification in the 1990s and, the last one, in 2005. Currently, five categories of cystic renal lesions are defined - namely, I, II, II-F, III and IV –, according to their degree of complexity and likelihood of malignancy. Despite being initially described for computed tomography, this classification has been also utilized with some advantages also for magnetic resonance imaging. The present article reviews the different phases of this classification, its diagnostic efficacy and the most controversial features of its use.