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The incidence of small renal masses is increasing, as a result of the wide adoption of imaging exams. Their management, however, is complicated, especially in patients with decreased life expectancy or comorbidities. Approximately 20% of small renal masses are benign and, even if malignant, just 10% show aggressive pathological features. Furthermore, competing cause mortality seems to exceed the cancer-specific mortality in patients aged over 70 years. The role of percutaneous tumor biopsy is still not well defined. All these observations raise the concern as to whether surgery might represent an overtreatment for some cases of small renal masses, calling into question the role of active surveillance. The aim of this review was to evaluate the current evidence pertaining to several hot questions that need to be addressed when contemplating active surveillance for small renal masses. The most relevant publications on this subject available in the literature were selected. Five representative series of active surveillance along with the main related variables were identified. Some relevant items surrounding the field of active surveillance were identified and submitted to an evidence-based discussion. According to the recent evidence, small renal masses under active surveillance tend to show an indolent course with a low probability of disease progression, the latter being triggered most of the time by a tendency to grow faster. Unfortunately, we are currently unable to predict those few cases with aggressive behavior. According to the current evidence, active surveillance is feasible and safe in elderly and comorbid patients. [ABSTRACT FROM AUTHOR]

Purpose: Stringent radiological follow-up is essential after renal tumor ablation. Drawbacks of postablation follow-up by contrast-enhanced computed tomography (CECT) are the associated ionizing radiation and nephrotoxic contrast agent. Contrast-enhanced ultrasound (CEUS) has shown potential to demonstrate microvasculature without using either ionizing radiation or toxic contrast agent. We assessed the concordance of enhancement patterns of CEUS and CECT/MRI in cryolesion assessment after laparoscopic renal cryoablation (LCA). Methods: From 01/2006 to 01/2009, a CEUS was performed before and after LCA (3 and 12 months) in addition to regular CECT/MRI. Using an enhancement score (0=no enhancement, 1=rim enhancement, 2=diffuse enhancement, 3=localized enhancement, 4=no enhancement defect), the cryolesion was assessed by both modalities, and concordance of enhancement score was assessed. Results: In total, 45 tumors were included (29 biopsy proven renal cell carcinoma (RCC), mean size 2.66 cm). One cryoablation failed, resulting in a nonenhancing cryolesion apart from the persisting renal tumor. There were no postablation recurrences during the study period. Pre-LCA: Both modalities were available in 26 cases. In 20 out of 26, there was concordance of enhancement score (77%, all cases score 3 or 4). Three months: Both modalities were available in 32 cases. Enhancement score corresponded in 23 out of 32 cases (72%). Seven cases showed enhancement on CECT/MRI ('1' in six cases, '4' in one case) with enhancement score '0'on CEUS. Two cases showed enhancement on CEUS without enhancement on CECT/MRI (specificity 92%, negative predictive value [NPV] 77%). Except one case, all enhancement resolved on subsequent imaging. Twelve months: Both modalities were available in 21 tumors. Enhancement score corresponded in 19 out of 21 cases (91%). Two cases showed enhancement on CEUS without enhancement on CECT/MRI (specificity 90%, NPV 100%). Conclusion: This pilot study shows that CEUS is a safe imaging technique with high concordance of enhancement score between CEUS and CECT/MRI. While cross-sectional imaging seems sensible to demonstrate successful ablation at first follow-up, CEUS might be used to diminish the burden of contrast-enhanced cross-sectional imaging in the long-term follow-up. [ABSTRACT FROM AUTHOR]

What's known on the subject? and What does the study add? Optical Coherence Tomography (OCT) was developed in the early 1990s for ophthalmological application and is currently widely accepted in ophthalmology for retinal imaging purposes. In kidneys, the first experiments were performed on transplant kidneys to investigate the ability of OCT to assess ischaemic damage of kidneys. An ex vivo pilot study on the ability of OCT to differentiate normal renal tissue from malignant renal tissue, showed positive results and here we present the results of the first in vivo experiment. The study shows for the first time that in vivo OCT is feasible and safe to perform in humans and that a significant different attenuation coefficient (as a quantitative measurement of the OCT images) is found between normal renal tissue and malignant renal tumours with a clear trend towards significance in the difference between benign and malignant renal tumours in a small pilot study. This suggests potential use of OCT in different clinical settings for diagnostic purposes in the course of renal tumours, and justifies further research. OBJECTIVE To determine the ability of optical coherence tomography (OCT) in differentiating human renal tumours in an in-vivo setting by assessing differences in attenuation coefficient (µOCT; mm-1) as a quantitative measurement., METHODS Consecutive patients undergoing nephrectomy (partial/radical) or cryoablation for an enhancing solid renal tumour were included in our centre between October 2010 and May 2011., In vivo OCT images were obtained from renal tumour and normal parenchyma during surgery. Ex vivo OCT images of internal (subcapsular) tissue were obtained after longitudinal dissection of the extirpated specimen., Attenuation coefficients of the OCT images were determined off-line and compared between normal renal parenchyma and renal tumours (grouped per tissue type and per individual patient); and between OCT images recorded from tissue surface vs internal (subcapsular) tissue., RESULTS In vivo OCT was performed in 16 cases (11 renal cell carcinoma, three benign tumours, one non-diagnostic biopsy and one not-accessible tumour)., Median attenuation coefficient of normal renal parenchyma was 5.0 mm−1 vs 8.2 mm−1 for tumour tissue ( P < 0.001) with normal parenchyma differing significantly from malignant tumour (9.2 mm−1, P < 0.001) and non-significantly from benign tumour (7.0 mm−1, P= 0.050). The attenuation coefficient of benign tumours did not differ significantly from that of malignant tumours (7.0 vs 9.2 mm−1, P= 0.139)., Using patients as their own control, attenuation coefficients of normal renal parenchyma differed significantly from malignant tumour ( P < 0.001) and non-significantly from benign tumour ( P= 0.109)., Assessed in 10 patients, there was no significant difference between attenuation coefficients of tumour surface and internal tumour (8.5 vs 9.7 mm−1 respectively, P= 0.260)., CONCLUSIONS In this first in vivo study on OCT for differentiation of renal tumours in humans the attenuation coefficients (as a quantitative assessment) differed significantly between normal renal parenchyma and malignant tumour., Tumour surface and internal tumour did not differ significantly, suggesting that a superficial OCT attenuation coefficient reliably assesses tissue composition inside the tumour., These results justify further research on OCT for various clinical applications in the diagnosis of renal tumours. [ABSTRACT FROM AUTHOR]

Purpose: To define in which patients who present with microscopic or macroscopic hematuria CT urography (CTU) is indicated as an imaging mode for the upper urinary tract (UUT). Patients and Methods: We conducted a prospective study on consecutive patients who attended a modern protocol-driven hematuria clinic from January 2006 to February 2010. Standard tests (history taking, physical examination, urinalysis via dipstick method, ultrasonography of kidneys and bladder performed by urologists, cystoscopy, and cytology) were directed to all patients, whereas the mode of additional UUT imaging (ultrasonography by a radiologist or four-phase CTU/magnetic resonance (MR) urography (MRU) when CTU was contraindicated) was selected according to a risk factor-based management algorithm. The added value of cross-sectional urography (CTU/MRU) supplementary to ultrasonography (by urologists) to detect renal masses, UUT tumors, and stones was assessed. Univariate and multivariate analysis on predictive factors for cross-sectional urography result were performed. Results: From the total of 841 patients, lesions that might account for hematuria could not be identified in 462 (54.9%), whereas in 250 (29.7%) and 124 (14.7%) patients, hematuria was from benign and malignant disease, respectively. Cross-sectional urography revealed relevant UUT lesions in 73 of 525 (13.9%) patients. Only result of ultrasonography (odds ratio [OR] 7.7, 95% confidence interval [CI] 4.0-14.9), P<0.001) and type of hematuria (OR 2.6, 95% CI 1.3-5.1, P=0.01) were significant predictors for cross-sectional urography result. In 44 of 456 (9.6%) patients with no abnormalities on ultrasonography, CTU/MRU revealed that these were false negatives, with most lesions missed being stones. In 253 of 309 (81.9%) patients with macroscopic hematuria, no lesions were detected in the UUT on CTU/MRU, in contrast to 199 of 216 patients (92.1%) with microscopic hematuria. Conclusion: For patients who present with microscopic hematuria, ultrasonography is sufficient to exclude significant UUT disease. For patients with macroscopic hematuria, the likelihood of finding UUT disease is higher, and a CTU as a first-line test seems justified. [ABSTRACT FROM AUTHOR]

Abstract: The diagnostic problems in the subtyping of renal tumors were evaluated by a panel of five pathologists studying a set of selected tumors. Five pathologists independently assessed a single hematoxylin-and-eosin (HE)-stained slide from 28 selected renal tumors. After this independent assessment, the pathologists reevaluated and discussed all discordant cases. Additional HE-stained sections and immunohistochemically (IHC) stained slides were available. The generalized kappa for interobserver agreement was calculated. After independent assessment of the HE-stained slides, the five pathologists unanimously reached an agreement in the decision between malignant and benign in 82% of the cases. Fifty percent of the cases were correctly subclassified. The overall generalized kappa value for the five pathologists was 0.320 (CI 95% 0.090–0.551), which is considered a moderate agreement. A 100% agreement was reached for all 28 cases after examination of more slides from different tumor areas and IHC-stained sections. An accurate histologic distinction between benign and malignant renal tumors is possible on one HE-stained section. Correct assignment of the subtype is difficult on one slide alone and relies on IHC-markers and additional slides. Tumors composed of an eosinophilic cell type and tumors with a papillary growth pattern were the major causes of an incorrect diagnosis on an HE-stained section alone. [Copyright &y& Elsevier]

Abstract: Background: Fine needle aspiration (FNA) cytology is under consideration as an auxiliary preoperative diagnostic technique in the diagnosis of renal masses. However, reports for FNA are contradictory with regard to diagnostic accuracy and applicability. Objective: To evaluate the diagnostic accuracy and reproducibility of FNA from renal masses. Design: FNAs performed in-bench (hematoxylin and eosin [H&E] stains) from 66 consecutive renal tumours (58 malignant and 8 benign tumours) were presented twice with a 6-mo interval to five pathologists with little experience in renal cytology. Pathologists were blinded for the results of the first round as well for the surgical specimen. The FNAs were stained for Papanicolaou and Giemsa. Measurements: Diagnostic accuracy, concordance between smears and surgical specimens, and the generalized kappa for interobserver/intraobserver agreement were calculated. Results and limitations: The number of nondiagnostic and nonconclusive cases ranged from 5–14% in the first and 3–8% in the second round. Overall accuracy varied between 73–89% and 71–91% for the first and second round, respectively. Sensitivity (72–97%) and positive predictive value (PPV) (93–100%) to classify a malignant tumour in both rounds was high. Sensitivity (25–100%) and PPV (28–100%) to classify a benign tumour was lower with a wide confidence interval. Overall concordance in subtyping ranged from 39–70% in the first, and from 52–74% in the second round. Interobserver agreement ranged from fair (κ =0.039) to substantial (κ = 0.540) for the different subtypes. The intraobserver agreement (mean κ = 0.357, CI 95%=0.304–0.411) was moderate for all pathologists. The low number of benign tumours in this study precludes sound statements regarding the diagnostic accuracy of FNA to classify benignity. Conclusion: Despite the lack of experience in renal cytology, all pathologists showed a high diagnostic yield and good overall accuracy in distinguishing between malignant and benign tumours. Concordance in subtyping varied widely among pathologists and was reliable only for clear cell renal cell carcinoma (ccRCC). These results suggest that FNA may have a potential role in the diagnosis of renal tumours although its value in subtyping was limited in our setting. [Copyright &y& Elsevier]