***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Most early stage kidney cancers are renal cell carcinomas ( RCCs ) , and most are diagnosed incidentally by imaging as small renal masses ( SRMs ) . Indirect evidence suggests that most small RCCs grow slowly and rarely metastasize . OBJECTIVE To determine the progression and growth rates for newly diagnosed SRMs stratified by needle core biopsy pathology . DESIGN , SETTING , AND PARTICIPANTS A multicenter prospect i ve phase 2 clinical trial of active surveillance of 209 SRMs in 178 elderly and /or infirm patients was conducted from 2004 until 2009 with treatment delayed until progression . INTERVENTION Patients underwent serial imaging and needle core biopsies . MEASUREMENTS We measured rates of change in tumor diameter ( growth measured by imaging ) and progression to ≥ 4 cm , doubling of tumor volume , or metastasis with histology on biopsy . RESULTS AND LIMITATIONS Local progression occurred in 25 patients ( 12 % ) , plus 2 progressed with metastases ( 1.1 % ) . Of the 178 subjects with 209 SRMs , 127 with 151 SRMs had>12 mo of follow-up with two or more images , with a mean follow-up of 28 mo . Their tumor diameters increased by an average of 0.13 cm/yr . Needle core biopsy in 101 SRMs demonstrated that the presence of RCC did not significantly change growth rate . Limitations included no central review of imaging and pathology and a short follow-up . CONCLUSIONS This is the first SRM active surveillance study to correlate growth with histology prospect ively . In the first 2 yr , the rate of local progression to higher stage is low , and metastases are rare . SRMs appear to grow very slowly , even if biopsy proven to be RCC . Many patients with SRMs can therefore be initially managed conservatively with serial imaging , avoiding the morbidity of surgical or ablative treatment PURPOSE To evaluate the feasibility and complications of ultrasound (US)-guided biopsy of small renal masses ( SRMs ) and to determine factors that contribute to nondiagnostic biopsy specimens . MATERIAL S AND METHODS Between June 2004 and May 2011 , 58 consecutive patients underwent US-guided core biopsy of a SRM ( > 1 cm and ≤4 cm ) using an 18-gauge core biopsy device .  The diagnostic rate , histologic diagnosis , and complications of US-guided core biopsy were assessed .  Mann-Whitney U  and  Fisher exact tests were used to compare diagnostic and nondiagnostic biopsy specimens . Univariate analysis was performed to determine the predictive factors for nondiagnostic biopsy specimens . RESULTS There were 59 biopsies of SRMs performed , and the diagnostic rate was 81 % ( 48 of 59 ) . The mass size of diagnostic and nondiagnostic biopsy specimens ranged from 1.2 - 3.9 cm ( 2.4 cm±0.7 ) for diagnostic specimens and from 1.1 - 3.5 cm ( 1.9 cm±0.7 ) for nondiagnostic specimens ( P = .024 ) . Of the diagnostic biopsy specimens , 77 % ( 37 of 48 ) were malignant , and 23 % ( 11 of 48 ) were benign . Minor complications developed in 20.3 % ( 12 of 59 ) of biopsies . The lesion size or core number threshold for decreasing diagnostic rate was 2 cm or three cores . A cystic mass , fewer cores ( three or fewer cores ) , an upper pole mass , and a small mass ( ≤2 cm ) significantly predicted a nondiagnostic biopsy specimen ( P = .007-.046 ) . CONCLUSIONS US-guided core biopsy is a feasible and safe procedure for histologic diagnosis of a SRM . However , nondiagnostic rates may increase when a cystic mass is biopsied , a mass is located in an upper pole mass , a mass is 2 cm or less , and three cores or fewer are sample OBJECTIVES To determine the accuracy and clinical utility of fine needle aspiration ( FNA ) of small , solid renal masses . METHODS A total of 25 patients with small ( less than 5.0 cm ) , solid , clinical ly localized renal masses were prospect ively identified and evaluated with computed tomography guided FNA with analysis for presence of malignant cells and determination of nuclear grade . The final pathologic findings were used for comparison in each case . All patients had renal cell carcinoma and were managed with radical or partial nephrectomy ; 3 had low- grade lesions ( Fuhrman 's grade 1/4 ) , 2 had high- grade lesions ( Fuhrman 's grade 4/4 ) , and all other patients had intermediate- grade lesions ( Fuhrman 's grade 2/4 or 3/4 ) on final histopathologic assessment . RESULTS Overall , 10 aspirations yielded diagnostic malignant cells , and 9 were read as rare as rare atypical cells suspicious for malignancy . The remainder were negative ( n = 6 ) . Correlation with final nuclear grade was observed in eight instances and discordance in two instances . Subcapsular hematomas were observed at the time of surgery in 10 patients , but in no instance was the operation adversely affected . CONCLUSIONS The diagnostic yield of FNA of small , solid renal masses appears to be too low to justify the potential morbidity of the procedure Purpose In some cases with uncertain renal tumour lesions , it would be helpful to perform biopsies for the preoperative differential diagnosis . In our study , we evaluated the benefit of multi-colour  interphase fluorescence in situ hybridization  ( M-FISH ) on fine-needle core biopsies in uncertain renal masses . Methods We prospect ively performed  three ultrasound-guided percutaneous biopsies in 25 patients with indeterminate renal masses preoperatively . Histopathology was performed on two remaining cores sample s. M-FISH was performed on one core for chromosomes 1 , 2 , 6 , 9 , 7 , 17 , the loci 3p24pter , and 3p13p14 . After interphase FISH evaluation , we classified tumours and compared the results with histopathological findings . Results 16 were classified as renal malignancies : 14 ( 56 % ) clear cell renal cell carcinomas ( RCCs ) , 1 papillary RCCs ( 4 % ) , and 1 “ adenocarcinoma ” ( 4 % ) . Seven patients ( 28 % ) had a benign tumour , i.e. 6 ( 24 % ) were oncocytomas and 1 was classified as leiomyoma ( 4 % ) . In two cases ( 8 % ) , no renal neoplasms were found . In 19 out of 21 cases ( 90.5 % ) , the preoperative diagnostic fine-needle biopsy matched the final histological findings . The combination of histopathological examination and M-FISH leads to a higher ( 95.5 vs. 90.5 % ) diagnostic fidelity as histology alone . Conclusions Ultrasound-guided percutaneous renal tumour biopsy is an accurate and safety method for the histopathologic evaluation of uncertain renal masses . The M-FISH represents a new highly sensitive and specific method to confirm histopathological classification in less than 24 h which can be used in routine laboratory diagnosis OBJECTIVES We evaluated the reliability of sonographic criteria in selecting solid renal masses for percutaneous fine-needle biopsy . METHODS In study 1 ( intraoperative ultrasound study ) , we prospect ively examined 100 consecutive patients scheduled for partial/radical nephrectomy by using two different high-resolution probes (  Philips HDI 5000 , CT8 - 4 , L12 - 5 ; 4 - 12MHz ) . The main tumor was intraoperatively evaluated by B-mode and power Doppler sonography . Morphologic characteristics seen on ultrasound were categorized in (non-)homogenous and (non-)cystic renal masses and were related to findings of pathological examination . Study 1 provided the selection criteria for study 2 . In study 2 ( percutaneous biopsy study ) , under local anesthesia and with the use of an 18-G needle , we prospect ively performed two to three sonographically guided percutaneous biopsies in 30 consecutive patients whose tumors appeared to be homogenous and noncystic according to the sonograph ( convex array 3.5MHz , HDI 5000 , C5 - 2 and Falcon 2101 EXL , B+K Medical ) . RESULTS In the ultrasound study , only 16 ( 22.9 % ) of the 76 clear-cell carcinomas but all 9 ( 100 % ) oncocytoma appeared homogenous and noncystic on high-resolution intraoperative ultrasound . By applying these results to 30 patients of study 2 ( 18 men , 12 women ; aged 63+/-7.7 yr , tumor size 29+/-11.3 mm ) who met these sonographic criteria on preoperative transabdominal ultrasound  , we bioptically diagnosed 8 ( 26.7 % ) benign tumors ; 25 of 30 ( 83.3 % ) patients were accurately diagnosed . Small tumors ( <3 cm ) , decreased breathing compliance , and medially located renal lesions seem to negatively influence biopsy results . CONCLUSIONS Kidney tumors that appear noncystic and homogenous on preoperative ultrasound are more likely to be of benign origin . Ultrasound-guided percutaneous biopsy of these solid renal masses could determine renal tumor patients for whom surveillance might be an option . However , experienced and dedicated histopathologic evaluation remains crucial to observe patients with clearly benign biopsy results . All even slightly question able biopsy findings require surgical exploration OBJECTIVE Modern imaging modalities increase the detection of small ( < or=4 cm ) renal tumors , of which about 20 % are benign . As a result , minimal invasive treatments , such as radiofrequency ablation and cryotherapy , and surveillance strategies are gaining popularity . Information that would be helpful when choosing the most appropriate management strategy for this patient group could be obtained from pretherapeutic image-guided biopsy . METHODS Under computed tomography (CT)-fluoroscopic guidance  78 patients with solid renal tumors prospect ively underwent 18-gauge core biopsy . In addition , using the same sheath , fine-needle aspiration was taken in 44 patients and analyzed cytologically . The renal masses were subsequently removed surgically and evaluated histologically . RESULTS Mean patient age was 63+/-13.5 yr ; mean tumor size was 4+/-1.8 cm . The sensitivity of  core biopsy and fine-needle aspiration for the detection of renal cell carcinoma ( RCC ) was 93.5 % and 90.6 % , respectively ; Fuhrman grade was correctly predicted in 76 % and 28 % and the correct histologic subtype was identified 91 % and 86 % , respectively . Cytology from fine-needle aspiration revealed a sensitivity in detecting malignant and benign lesions of 100 % and 75 % , respectively . Two of the renal tumors diagnosed as oncocytomas on core biopsy were hybrid tumors with scattered areas of oncocytomas and chromophobe RCC . Complications of CT-guided biopsy included one marginal pneumothorax , which resolved under conservative management , and four small perirenal hematomas detected at follow-up ultrasonography not requiring further therapy . CONCLUSION CT-guided percutaneous preoperative renal tumor biopsy had a high diagnostic accuracy , particularly in predicting malignancy BACKGROUND Percutaneous needle core biopsy has become established in the management of small renal masses ≤ 4 cm ( SRMs ) . Recent series have reported success rates of ≥ 80 % . Nondiagnostic results continue to be problematic . OBJECTIVE To determine the results of SRM biopsy and the outcomes of nondiagnostic biopsy and repeat biopsy . DESIGN , SETTING , AND PARTICIPANTS Patients undergoing renal tumor biopsy ( RTB ) for suspected renal cell carcinoma ( RCC ) were included in a prospect ively maintained data base . MEASUREMENTS The data base was analyzed retrospectively to determine the pathology and outcomes of SRM biopsy . Outcomes of patients with nondiagnostic biopsy  were determined . Patients undergoing repeat biopsy were identified and their outcomes analyzed . RESULTS AND LIMITATIONS Three hundred forty-five biopsies were performed ( mean diameter : 2.5 cm ) . Biopsy was diagnostic in 278 cases ( 80.6 % ) and nondiagnostic in 67 cases ( 19.4 % ) . Among diagnostic biopsies , 221 ( 79.4 % ) were malignant , 94.1 % of which were RCC . Histologic subtyping and grading of RCC was possible in 88.0 % and 63.5 % of cases , respectively . Repeat biopsy was performed in 12 of the 67 nondiagnostic cases , and a diagnosis was possible in 10 ( 83.3 % ) . Eight lesions were malignant and two were oncocytic neoplasms . Pathology was available for 15 masses after initial nondiagnostic biopsy ; 11 ( 73 % ) were malignant . Larger tumor size and a solid nature on imaging predicted 
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CONCLUSIONS RTB is safe and has a high diagnostic yield in experienced centres .
Both CB and FNA have good accuracy for the diagnosis of malignancy and histologic subtype , with better performance for CB .
The accuracy for Fuhrman grade is fair .
The results suggest that RTB has good accuracy in diagnosing renal cancer and its subtypes , and it appears to be safe .