Evaluation of fine-needle aspiration cytology for renal masses

Perioperative characteristics, histologic diagnosis, complications, and outcomes of dogs undergoing percutaneous drainage, sclerotherapy or surgical management of intrarenal cystic lesions: 18 dogs (2004-2021)

BACKGROUND

Canine intrarenal cystic lesions (ICLs) are infrequently reported in the veterinary literature. Several treatment options have been described including cyst fenestration (partial nephrectomy/deroofing) +/- omentalization, sclerotherapy using alcohol as a sclerosing agent, percutaneous cyst drainage (PCD), and ureteronephrectomy. Information regarding presenting clinical signs, physical examination findings, histologic diagnosis and outcomes of dogs with ICLs treated by different methods is limited. Medical records of 11 institutions were retrospectively reviewed to identify dogs that underwent PCD, sclerotherapy, surgical deroofing +/- omentalization, or ureteronephrectomy for management of ICLs from 2004 to 2021. Six weeks postoperative/post-procedural follow-up was required. Cases suspected to represent malignancy on preoperative imaging were excluded. The study objective was to provide information regarding perioperative characteristics, complications, and outcomes of dogs undergoing treatment of ICLs.

RESULTS

Eighteen dogs were included, with 24 ICLs treated. Ten had bilateral. There were 15 males and 3 females, with crossbreeds predominating. PCD, sclerotherapy, deroofing and ureteronephrectomy were performed in 5 (5 ICLs treated), 7 (11 ICLs), 6 (6), and 7 (7) dogs, respectively, with 5 dogs undergoing > 1 treatment. Seven dogs experienced 8 complications, with requirement for additional intervention commonest. PCD, sclerotherapy and deroofing resulted in ICL resolution in 0/5, 3/11 and 3/6 treated ICLs, respectively. Histopathology identified renal cysts (RCs) in 7/13 dogs with histopathology available and neoplasia in 6/13 (4 malignant, 2 benign). Of 5 dogs diagnosed histopathologically with neoplasia, cytology of cystic fluid failed to identify neoplastic cells. Among 7 dogs with histologically confirmed RCs, 4 had concurrent ICLs in ipsilateral/contralateral kidney, compared with 2/6 dogs with histologically confirmed neoplasia.

CONCLUSIONS

Benign and neoplastic ICLs were approximately equally common and cystic fluid cytology failed to differentiate the 2. Among renal-sparing treatments, deroofing most commonly resulted in ICL resolution. Presence of concurrent ICLs in ipsilateral/contralateral kidney does not appear reliable in differentiating benign from malignant ICLs.

Improving ROSE: Discrepant touch preparation and histology findings in cytology of renal masses: A 10-year retrospective review

BACKGROUND

The number of "renal incidentalomas" is on the rise due to increasing use of radiologic studies. Image-guided core needle biopsies (CNB) with touch preparations are performed to guide specimen collection and triage of sample for additional studies. Results allow the clinical team to make appropriate treatment decisions.

DESIGN

Our electronic database was searched for a 10-year period to identify 180 image-guided biopsies of renal masses with rapid on-site evaluations (ROSE) and corresponding biopsy/resection specimens. Touch preparations were classified as non-diagnostic, negative/benign, adequate/positive for malignancy/oncocytic predominance, or atypical. These results were compared to the final diagnosis on the biopsy or resection specimen (if available). Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were determined. Non-diagnostic cases and cases in which ROSE and final diagnosis were discordant were reviewed by cytopathologists blinded to the original interpretation to reconcile discrepancies and highlight interpretation pitfalls.

RESULTS

A ROSE diagnosis was rendered in 133 of 180 cases; 47 cases were non-diagnostic. Of the 133 diagnostic cases, the ROSE diagnosis was concordant with the core biopsy final diagnosis in 125 cases, yielding a diagnostic accuracy of 94%. The overall sensitivity was calculated to be 80.1%; specificity 72.4%; positive predictive value 94%; and negative predictive value 41.2%.

CONCLUSIONS

Touch preparation slides are vital but imperfect tools in evaluating renal masses. In our study, distinction between malignant and benign samples was accomplished in most cases (94% accuracy), but there are limitations. Awareness of interpretation pitfalls allows informed decisions to be made regarding specimen collection and patient management.

Percutaneous image-guided core biopsy of solid renal masses: analysis of safety, efficacy, pathologic interpretation, and clinical significance

PURPOSE

To determine the efficacy, safety and clinical utility of CT and US-guided percutaneous renal mass biopsy.

MATERIALS AND METHODS

A retrospective IRB-approved, HIPAA-compliant study of a cohort of 183 consecutive patients who underwent percutaneous, CT or US-guided renal mass biopsy (RMB) from March 2002 through December 2012 was performed. RMB was performed in 183 consecutive patients for suspected solid renal mass of whom 14/183 (7.7%) were excluded because biopsies were performed at an outside institution, medical records were incomplete, or lesions were poorly visualized. Ten patients had multiple biopsies for new growing masses. Using US, CT or CT/US fusion-guidance, a 17G or 19G cannula needle was placed at the margin of the mass and an 18G or 20G core biopsy gun was used to obtain several tissue cores. Renal parenchymal biopsies for medical renal diseases were excluded. Imaging variables (including size, location, and extent of disease), number of core biopsies, patient demographics (age, gender), clinical indication, final pathologic diagnosis, immunohistochemical (IHC) studies, and subsequent final pathological diagnosis on nephrectomy were evaluated.

RESULTS

Of the 169 patients with 184 RMB, 121/169 (71.6%) were male with a mean age of 67.5 years. Of 184 RMB, 126 were malignant [126/184 (68.5%)], 37 [37/184 (20.1%)], were benign, and 21 (21/184 (11.4%) were nondiagnostic. IHC was performed in 131 biopsies (71.1%) and was diagnostic in 88.5% of those cases. Twenty-eight patients underwent subsequent partial nephrectomy; in 27/27 (100%) cases, RMB was concordant with nephrectomy for malignancy and in 21/27 (77.8%) RMB was concordant for subtype of RCC. Overall, the RMB sensitivity for detection of malignancy, specificity, and positive predictive value were 100%. The negative predictive value of benign RMB diagnosis was also 100%. There was a total of 14 (7.6%) complications, 13 minor (7.1%) and 1 major (0.5%). Of the minor complications, ten (5.5%) were postprocedural minor hematomas that resolved conservatively; one (0.5%) postprocedural vasovagal reaction; one (0.5%) episode of hematuria; and one (0.5%) episode of nausea and abdominal discomfort. No cases of renal pseudoaneurysm or tumor seeding attributed to biopsy were identified.

CONCLUSION

Percutaneous image-guided RMB is safe and highly diagnostic when combined with IHC and supports a greater role of RMB and imaging in evaluating renal masses when rendering appropriate treatments.

Percutaneous ultrasound-guided renal biopsy; A comparison of axial vs. sagittal probe location

BACKGROUND

Renal biopsy is an important method for diagnosis of renal parenchymal abnormalities. Here, we compare the effectiveness and complications of percutaneous ultrasound-guided renal biopsy using axial vs. sagittal probe locations.

METHODS

In a cross-sectional survey, in 2012, patients with a nephrologist order were biopsied by a radiology resident. Renal biopsy was done on 15 patients using axial (A group) and the same number of biopsies done with sagittal probe location (S group). The two groups were compared in term of the yields and complications of each method.

RESULTS

In the A group, the ratio of glomeruli gathered to the number of obtained samples was significantly higher than in the S group. Nine patients in the A group (60%) required only two samplings, whereas 66.7% in the S group required more than two attempts. Microscopic hematuria was more common in the A; conversely, gross hematuria was less common in the A group. Meagre hematomas were more frequent in the S group. When compared with hemoglobin level before biopsy, its level 24 hours after biopsy was similar within groups.

CONCLUSION

Our study shows that percutaneous ultrasound-guided renal biopsy using axial probe provides better yield with fewer efforts and fewer serious complications.

Smears are important for adequate cytologic diagnosis of kidney lesions

INTRODUCTION

Traditionally at our institution, smears with or without liquid-based cytology (LBC) and core biopsies (CBs) have been obtained by radiologists performing image-guided fine-needle aspiration biopsies (FNABs) of deep organs. Since 2015, however, there has been a shift to providing cytology with samples for LBC only when obtaining CBs. The impression among our institution's cytologists is that LBC alone is less often adequate for diagnosis compared with smears and LBC together. We examined a series of kidney FNABs pre- and post-"LBC only" to evaluate this impression.

MATERIALS AND METHODS

With institutional review board approval, we compared all kidney FNABs from 2012 to those from 2015. We recorded the type(s) of cytology preparation(s), the number of cytology slides, the cytology diagnosis, the concurrent CB diagnosis, and whether there was a subsequent excision and the excision diagnosis. We examined cytology and CB slides as needed.

RESULTS

In 2012, 105 patients underwent 111 kidney biopsies, 109 with smears made. In 2015, 58 patients underwent 62 kidney biopsies, 7 with smears made. In 2012, there were 13 (12%) nondiagnostic (ND) cytology cases and 19 (17%) cases where the cytology and CB diagnoses were discrepant. By comparison, in 2015, there were 20 (32%) ND cytology cases and 21 (33%) discrepant cases.

CONCLUSIONS

There were more cytology slides per case and fewer ND diagnoses in 2012 compared with 2015 (12% versus 32%, respectively, P = 0.001). Concordance was also better in 2012 (83% versus 67%, P = 0.015). We believe that our metrics would improve if we returned to the procedures followed in 2012.

Renal Tumor Biopsy Technique

Objective:

To review hot issues and future direction of renal tumor biopsy (RTB) technique.

Data Sources:

The literature concerning or including RTB technique in English was collected from PubMed published from 1990 to 2015.

Study Selection:

We included all the relevant articles on RTB technique in English, with no limitation of study design.

Results:

Computed tomography and ultrasound were usually used for guiding RTB with respective advantages. Core biopsy is more preferred over fine needle aspiration because of superior accuracy. A minimum of two good-quality cores for a single renal tumor is generally accepted. The use of coaxial guide is recommended. For biopsy location, sampling different regions including central and peripheral biopsies are recommended.

Conclusion:

In spite of some limitations, RTB technique is relatively mature to help optimize the treatment of renal tumors.

Systematic Review and Meta-analysis of Diagnostic Accuracy of Percutaneous Renal Tumour Biopsy

CONTEXT

The role of percutaneous renal tumour biopsy (RTB) remains controversial due to uncertainties regarding its diagnostic accuracy and safety.

OBJECTIVE

We performed a systematic review and meta-analysis to determine the safety and accuracy of percutaneous RTB for the diagnosis of malignancy, histologic tumour subtype, and grade.

EVIDENCE ACQUISITION

Medline, Embase, and Cochrane Library were searched for studies providing data on diagnostic accuracy and complications of percutaneous core biopsy (CB) or fine-needle aspiration (FNA) of renal tumours. A meta-analysis was performed to obtain pooled estimates of sensitivity and specificity for diagnosis of malignancy. The Cohen kappa coefficient (κ) was estimated for the analysis of histotype/grade concordance between diagnosis on RTB and surgical specimen. Risk of bias assessment was performed (QUADAS-2).

EVIDENCE SYNTHESIS

A total of 57 studies recruiting 5228 patients were included. The overall median diagnostic rate of RTB was 92%. The sensitivity and specificity of diagnostic CBs and FNAs were 99.1% and 99.7%, and 93.2% and 89.8%, respectively. A good (κ = 0.683) and a fair (κ = 0.34) agreement were observed between histologic subtype and Fuhrman grade on RTB and surgical specimen, respectively. A very low rate of Clavien ≥ 2 complications was reported. Study limitations included selection and differential-verification bias.

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. Overall, the quality of the evidence was moderate. Prospective cohort studies recruiting consecutive patients and using homogeneous reference standards are required.

PATIENT SUMMARY

We systematically reviewed the literature to assess the safety and diagnostic performance of renal tumour biopsy (RTB). The results suggest that RTB has good accuracy in diagnosing renal cancer and its subtypes, and it appears to be safe. However, the quality of evidence was moderate, and better quality studies are required to provide a more definitive answer.

Role of percutaneous needle biopsy for renal masses

The role of percutaneous renal mass biopsy has expanded considerably in the past 10 years. The incidence of incidentally detected small (< 4 cm) solid renal masses is on the rise, and despite a commensurate increase in nephron-sparing treatment, the mortality rate from renal cell carcinoma remains the same. Earlier detection and treatment have not had dramatic effects on population outcome, implying that not all small renal masses will grow to be life-limiting. Indeed, many small solid renal masses are benign, and among those that are malignant, not all share the same malignant behavior. Percutaneous biopsy provides a minimally invasive method for discriminating benign from malignant renal masses, and portends the potential for stratifying malignant risk. With recent improvements in image-guided equipment and technique, percutaneous renal mass biopsy can be performed safely and effectively, with a low complication rate (< 5%) and a high diagnostic yield (> 90%).

Genitourinary cytopathology (kidney and urinary tract)

FNA of kidney masses have been performed for the diagnosis of mass lesions,confirmation of advanced neoplasia and metastases, and staging of tumors. In the past, the decision of whether to perform a nephrectomy used to be based on radiographic features and size, precluding the use of FNA. Today, where treatment is not limited to surgery alone, the indications for renal FNA have expanded. Most small renal masses are asymptomatic and are detected incidentally due to improved imaging techniques. Although most urologists agree that the standard of care for renal masses is surgery, if the patient is an elderly individual, or has comorbidities a preoperative FNA could be useful in guiding the management.When we look at data from large referral institutions such as Mayo Clinic, Johns Hopkins Medical Institutions, and the Cleveland Clinic approximately 30 %of the renal masses are benign [86---88]. Therefore, as astutely pointed out by Volpe et al.[3], there is a role for precise pretreatment characterization of the renal masses by FNA, which would decrease the unnecessary treatment for benign diseases and reduce the treatment-related mortality and morbidity in addition to reducing patient care costs.To date, urine cytology remains the gold standard for bladder cancer screening.It has been, and still is, the test against which all new tests are compared when evaluating potential bladder tumor markers. The answer to whether urine cytology possesses the optimal combination of sensitivity and specificity to retain consideration as the best screening device depends on the goals of the practice. Urine cytology has excellent specificity with only few false-positive cases. Its overall sensitivity (including both high grade and low grade lesions) is poor, but this is explained by poor criteria for identifying well-differentiated, low-grade urothelial carcinoma in cytology. The natural history of low grade lesions is that of multiple superficial recurrences in 70 - 80 % of patients, with only a minority ( 10-15 %)progressing to muscle invasive or metastatic disease [89]. Patients with low-grade urothelial carcinoma are at low risk for progression, they are monitored primarily for the development of a subsequent high grade tumor [90]. Therefore, as suggested by Koss, detection of new low-grade lesions may be clinically irrelevant as compared to early detection of disease progression [39]. Contrary to the low grade lesions, however, urine cytology often results in the identification of high-grade malignant cells even before a cystoscopically distinguishable gross lesion is present. In the last 20 years, a number of noninvasive test have been developed to detect urothelial carcinoma. Although some have been able to show a better sensitivity compared to cytology, only a few have been close to reaching the sensitivity seen in cytology. Most of these tests have not added much to the diagnostic evaluation. Combining some of the new markers with each other and/or cytologic evaluation may optimize their performance status.

[Imaging renal cell carcinoma]

Renal cell carcinoma is the eighth most common malignancy in adults and the most common malignancy in the kidney. It is thus a very common disease for radiologists. This review aims to provide a general overview of the imaging techniques used to diagnose, characterize, and help plan the treatment of renal cell carcinoma as well as to review basic aspects related to staging, imaging-guided percutaneous treatment, and follow-up in the most common clinical scenarios.

Renal cell carcinoma seeding of a percutaneous biopsy tract

We report the case of a 68-year-old male with extension of papillary renal cell carcinoma (Fuhrman grade III) along a percutanous biopsy tract detected at the time of partial nephrectomy. Biopsy was performed to a obtain tissue diagnosis of a complex renal cyst as the patient was unable to receive intravenous contrast for imaging due to a severe allergy. Although biopsy of indeterminate renal lesions can provide valuable diagnostic information, there are inherent risks associated with this procedure. The rare occurrence of tumour seeding should be considered when recommending percutaneous biopsy to a patient with a renal mass.

Ablative therapies for renal tumors

Owing to an increased use of diagnostic imaging for evaluating patients with other abdominal conditions, incidentally discovered kidney masses now account for a majority of renal tumors. Renal ablative therapy is assuming a more important role in patients with borderline renal impairment. Renal ablation uses heat or cold to bring about cell death. Radiofrequency ablation and cryoablation are two such procedures, and 5-year results are now emerging from both modalities. Renal biopsy at the time of ablation is extremely important in order to establish tissue diagnosis. Real-time temperature monitoring at the time of radiofrequency ablation is very useful to ensure adequacy of ablation.

Is there a contemporary role for percutaneous needle biopsy in the era of small renal masses?

OBJECTIVE

To evaluate based on the best available data whether there is a contemporary role for percutaneous needle biopsy in the era of small renal masses.

PATIENTS AND METHODS

SRMs are acknowledged to be tumours less than 4cm and account for 48%-66% of new kidney cancers. Renal mass biopsy (RMB), traditionally limited to specific clinical scenarios and with inherent diagnostic accuracy problems has increased in popularity in recent years and is a potential valuable tool in the assessment of SRMs. Our discussion focuses on these issues. We performed a thorough Medline literature review using a combination of the following keywords; small renal mass, renal biopsy, percutaneous renal biopsy, renal mass biopsy and renal cell carcinoma. We identified the seminal articles with data/information pertaining to renal mass biopsy in small renal masses.

RESULTS

The facts that 1) a significant number of SRMs are diagnosed in an elderly patient cohort, 2) 20% of SRMs are benign on formal histology, 3) there are various management strategies now available and 4) modern RMB has a diagnostic accuracy >90% with few complications, are all reasons why there has been renewed interest in RMB.

CONCLUSION

  There is a contemporary role for RMB in the era of SRM as the incorporation of molecular profiling of tissue from RMB would augment our ability to risk stratify SRMs on an individual patient basis and adopt management accordingly. However, clinical judgement is paramount as there remains an unpredictable non-negligible risk of disease progression and metastasis whilst on surveillance.

The current role of renal biopsy in the management of localized renal tumors

Introduction:

In the current era of nephron-sparing surgery (NSS) for localized tumors, pretreatment tissue biopsy is being revisited and re-evaluated. Whether a renal biopsy can supplement imaging investigations to change patient management is a subject of current research.

Materials and Methods:

We performed a database search in PubMed for manuscripts from 1988 to 2008 using the appropriate keywords. Manuscripts were selected according to their relevance to the current topic and incorporated into this review.

Results:

Preoperative renal biopsy has been utilized to effectively distinguish between benign and malignant tumors localized to the kidney with minimal additional morbidity attributable to the procedure. Tissue diagnosis can also potentially grade renal tumors and uncover unusual malignancies. Although its acceptance remains limited, with fear of false negative results, bleeding and tumor seeding, its ability to influence management decisions has been demonstrated in literature.

Conclusions:

The role of preoperative renal biopsy for localized renal tumors is likely to increase rapidly in the coming times. With the expanding scope and utilization of NSS, this diagnostic modality will find increased applicability and acceptance in individualizing management protocols in the future.

Can renal oncocytoma be distinguished from chromophobe renal cell carcinoma by the presence of fibrous capsule?

The most important differential diagnosis of chromophobe renal cell carcinoma (CRCC) is renal oncocytoma. Due to overlapping morphological characteristics of renal oncocytoma and CRCC, particularly its eosinophilic variant, making a correct diagnosis can be challenging. To date, no data are available on the presence of the tumor fibrous capsule as a diagnostic feature in differentiating these tumors. The main purpose of this study was to establish the presence and compare the thickness of the tumor fibrous capsule between two tumor groups. A total of 37 tumors--18 cases of CRCC (three eosinophilic and 15 classic) and 19 cases of renal oncocytoma--were analyzed. Four slides of each tumor stained with hematoxylin and eosin were first scanned at low-power magnification (x40) to assess the presence of the capsule. If present, the capsule was measured in three different thickest areas at higher magnification (x200). The mean value of capsule thickness was calculated and taken into consideration. The capsule was present in 12 (66.7%) cases of CRCCs and in only two (10.5%) cases of renal oncocytomas. Statistical analysis showed significant difference between the presence of fibrous capsule in these two observed tumor groups (P = 0.001). Average thickness of capsule in CRCCs was 337.7 microm, and 115.4 microm in renal oncocytomas, but the median was not statistically significant (P = 0.198). Studies with a larger number of cases are needed to conclude if this characteristic could be a low-cost, reliable microscopic feature in differentiating between CRCC and renal oncocytoma.

EUS-guided FNA aspiration of kidney masses: a multicenter U.S. experience

BACKGROUND

Tissue sampling of renal lesions is traditionally performed with percutaneous US or CT guidance. To date, only 3 known cases of EUS-guided FNA (EUS-FNA) of a renal mass have been reported.

OBJECTIVE

To describe a multicenter experience with the indications, yield, and complications from attempted EUS-FNA of a kidney mass.

DESIGN

Retrospective case series.

SETTING

Six tertiary referral hospitals in the United States.

PATIENTS

Consecutive subjects undergoing attempted EUS-FNA of a kidney mass. Endosonographers at 15 other teaching hospitals were contacted regarding EUS findings and follow-up of any EUS-guided renal biopsies previously attempted or considered at that institution.

INTERVENTIONS

EUS-FNA of a kidney mass.

MAIN OUTCOME MEASUREMENTS

Biopsy indications, yield, diagnosis, and complications.

RESULTS

Fifteen procedures in 15 patients (9 men; median age 67 years) were performed at 6 (37%) of 16 hospitals (Indiana University plus 15 other hospitals). Kidney masses (median diameter 32 mm; range 11-60 mm) were located in the upper (n = 12) and lower (n = 3) poles of the left (n = 10) and right (n = 5) kidneys, respectively. Initial mass detection was by previous imaging in 13 (87%) patients or by EUS in 2 (13%) patients. Results of EUS-FNA (median 3 passes; range 2-4 passes) in 13 (87%) procedures were diagnostic of (n = 7) or highly suspicious for (n = 1) renal cell carcinoma (RCC), atypical cells (n = 2), oncocytoma (n = 1), benign cyst (n = 1), and nondiagnostic (n = 1). No complications were encountered. Surgical resection confirmed RCC in 7 patients in whom preoperative EUS-FNA demonstrated RCC (n = 5) or oncocytoma (n = 1) or was not performed (n = 1).

LIMITATIONS

Retrospective series, small number of patients.

CONCLUSIONS

EUS-FNA of renal masses is rarely performed at the U.S. teaching hospitals surveyed. This technique appears safe and feasible and should be considered when results would affect patient management.

Renal tumor natural history: the rationale and role for active surveillance

Renal cell carcinoma (RCC) is the most common malignancy of the kidney. Despite widespread treatment at diagnosis, overall mortality rates associated with RCC have not decreased. Partly because of the more frequent use of abdominal imaging, diagnosis as an incidental finding has increased. The largest increase in incidence is in tumors smaller than 4 cm, termed small renal masses (SRMs). SRMs that are RCC may frequently be growth slowly and have a low risk of early progression. Initial active surveillance with delayed treatment for progression for selected patients should be considered. This should result in an overall decrease in treatment burden and cost saving.

Interventional uroradiology

With advances in imaging capabilities and percutaneous instruments, many urologic diseases that were once managed surgically are now managed with minimally invasive image-guided techniques. Interventional uroradiology has evolved from simple renal biopsies for diagnostic confirmation, to percutaneous management of stones, to ablation of renal and adrenal tumors. Central to this evolution is the close cooperation with the urologist and nephrologist, each of whom provides specific skill sets and knowledge that can be used to successfully manage the patient. The purpose of this article is to detail the wide range of image-guided interventional techniques, including a discussion of indications, methods, success rates, and complications.

Pathologic concordance of sporadic synchronous bilateral renal masses

OBJECTIVES

To review the collective experience evaluating pathologic concordance rates of sporadic bilateral synchronous renal tumors reported in the Surveillance, Epidemiology, and End Results (SEER) database and the published English literature and treated at Fox Chase Cancer Center; specifically, to analyze concordance rates of malignant versus benign disease, histologic type, tumor stage, and nuclear grade.

METHODS

We reviewed the SEER database, the published English language literature, and our own institutional tumor registry to identify all cases of sporadic, synchronous localized (cT1-3N0M0) bilateral renal masses. Malignant and benign concordance rates were defined as agreement of any benign or malignant tumor type bilaterally. Histologic concordance was defined as bilateral histologic agreement. Tumors with mixed histologies were discordant unless all patterns were identical bilaterally. Nuclear grades were concordant if bilateral tumors were either "high" grade or "low" grade.

RESULTS

The malignant concordance rate in the SEER data was 99% (273 of 274), and benign concordance was 0 (0 of 1). In the published literature and Fox Chase Cancer Center series, malignant concordance rates ranged from 84% to 95%, whereas benign concordance ranged from 39% to 67%. The SEER data revealed a histologic concordance rate of 93% (256 of 274), and nuclear grade concordance was 85% (88 of 103).

CONCLUSIONS

These data demonstrate that in cases of bilateral sporadic localized synchronous renal masses, a diagnosis of ipsilateral renal cell carcinoma is associated with contralateral renal cell carcinoma in the vast majority of patients, whereas ipsilateral benign pathology is associated with contralateral benign disease at a substantially lower rate. Histologic concordance is similarly high, meaning most cases of clear cell or papillary tumors ipsilaterally are concordant in the contralateral kidney. Concordance rates of nuclear grade were slightly lower. These data are important when counseling and managing patients with bilateral synchronous sporadic renal tumors.

[Usefulness of cytology in diagnosis and management of renal and perirenal tumors in adults]

INTRODUCTION

The use more and more extended of tumorectomy, partial nephrectomy and nonsurgical treatments of renal tumors has supposed a renewed interest in the diagnosis use of cytology. Whether during preoperative period, through the puncture aspiration with fine needle (PAAF), or during the intraoperative analysis, the cytology offers the possibility of a specific morphologic diagnosis. In this revision the information concerning the diagnostic value of the cytology in renal tumors is updated.

MATERIAL AND METHODS

The references related to renal masses cytological descriptions has been reviewed. For this purpose we have searched both with computer in Medline data base and also manually. In the same way we include authors experience as much in the PAAF of these lesions as in the intraoperative use of the cytology.

RESULTS

Between neoplasias with more cytological typical presentation are the clear cell renal and papillary carcinomas. The chromophobe and oncocytoma can show similarities, although the accumulated experience in the last years reflects that its differentiation is possible in most of the cases. For the diagnosis of angiomyolipoma, urothelial carcinoma and kidney metastasis, the clinical and image information are of great interest for the pathologist. The integration of these data usually allows a specific diagnosis.

CONCLUSION

Generally, cytology reflects with accuracy the histological characteristics of renal neoplasias, allowing in many cases a specific diagnosis. We consider much appropriated the use of cytology, due to the more and more frequent situation of "incidentaloma". The PAAF minimum invasive nature and the possibility of performing a fast cytological analysis during intraoperative studies offer important information for the therapeutic management of these patients.

[Differential diagnosis of changes in kidney tumors of a small size]

The paper is aimed at presenting several patients treated at the CCS Institute of Urology and Nephrology using the retrospective analysis, in whom differentiation of the kidney tumor change nature and size smaller than 3 cm were decisive for further treatment. Similar cases were not reported or were reported exceptionally rarely in the literature. The diagnosis was established based on ultrasound examination, intravenous urography, computed tomography, magnetic resonance imaging as well as angiography, percutaneous biopsy and pathohistological analysis of the surgical preparation.

[Imaging features of xanthogranulomatous pyelonephritis]

Pseudotumoral xanthogranulomatous pyelonephritis is a rare chronic renal infection. Preoperative diagnosis is difficult because of its non-specific presentation. The purpose of this retrospective review of 8 cases is to assess the value of different imaging techniques in the evaluation of this pathology. Six males and 2 females, aged 29 to 75 years were included. The right kidney was involved in 5 cases and the left kidney was involved in 3 cases. Involvement was upper polar in 2 cases and lower polar in 6 cases. A kidney stone was present in 3 cases. US showed a heterogeneous hypoechoic lesion in 3 cases, a homogeneous hypoechoic lesion in 3 cases, and isoechoic lesion in 1 case and a cystic lesion in 1 case. CT showed a focal solid lesion with peripheral enhancement in 4 cases and a cystic mass with peripheral enhancement in 3 cases. US features are non-specific. CT shows a non-specific renal mass, the presence of obstruction and demonstrates perirenal involvement. Preoperative MRI, not performed in our patient population, demonstrates specific changes in the perirenal fat that suggests the diagnosis. The diagnosis of pseudotumoral xanthogranulomatous pyelonephritis can be suspected on a constellation of clinical and laboratory findings combined with non-specific features on CT and US and specific MRI features of perirenal fat changes. Percutaneous biopsy may be needed in selected cases to confirm diagnosis.

Techniques, Safety and Accuracy of Sampling of Renal Tumors by Fine Needle Aspiration and Core Biopsy

PURPOSE

The incidence of renal cell carcinoma is increasing worldwide and there are new treatments for localized as well as metastatic tumors. The traditional role for percutaneous biopsy of renal masses has been limited, and so there is little general experience. There have been concerns about safety and accuracy. This review provides an update on the current techniques, indications and accuracy of needle biopsy of renal tumors.

MATERIALS AND METHODS

PubMed and MEDLINE were searched for English language reports of percutaneous needle core biopsy and fine needle aspiration of renal tumors that were published from 1977 to 2006.

RESULTS

With the development of new biopsy techniques and wider experience with percutaneous probe ablation therapies the risk of tumor seeding appears negligible. Significant bleeding is unusual and almost always self-limiting. At centers with expertise needle core biopsy with or without fine needle aspiration appears to provide adequate specimens for an accurate diagnosis in more than 90% of renal masses.

CONCLUSIONS

Percutaneous biopsy of renal masses appears to be safe and it carries minimal risk of tumor spread. Urologists should consider increasing the indications for renal biopsy of small renal masses that appear to be renal cell carcinoma, especially in elderly and unfit patients. With more experience and followup preoperative biopsy has the potential to decrease unnecessary treatment since up to a third of small renal masses are now reported to be benign at surgery. Percutaneous biopsy may also allow a better selection of renal tumors for active surveillance and minimally invasive ablative therapies. Finally, there is potential for stratifying initial therapy for metastatic renal cell carcinoma by histological subtype and in the future molecular characteristics.

CT-guided biopsy for the diagnosis of renal tumors before treatment with percutaneous ablation

OBJECTIVE

Percutaneous thermal ablation is an emerging technique in the management of renal cell carcinoma (RCC), with greatest efficacy in tumors < or = 3 cm. The purpose of this retrospective study was to evaluate the role and utility of pretreatment CT-guided biopsy in patients referred for percutaneous thermal ablation of renal tumors.

CONCLUSION

Less than 5% of samples in our study were benign, and 11.8% were nondiagnostic. Biopsy in smaller lesions was less accurate; therefore biopsy is less useful for these renal lesions. Because fine-needle aspiration (FNA) has higher sensitivity than core biopsy, an appropriate algorithm may be to begin with FNA and reserve core biopsy for cases in which an onsite cytotechnologist is unavailable or deems the sample of inadequate cellularity.

Contrast-enhanced ultrasonography in the follow-up of cryoablation of renal tumours: a feasibility study

OBJECTIVE

To determine whether evaluating perfusion patterns with contrast-enhanced ultrasonography using contrast-pulse sequence imaging (CPS; a new imaging method that enables selective visualization of perfusion) is possible at different times after cryoablation of renal tumours, and to describe the characteristics of CPS in a small group of patients.

PATIENTS AND METHODS

The efficacy of renal cryoablation is mainly judged using imaging. Seven randomly selected patients, each at a different time after laparoscopically assisted cryoablation of a renal tumour, were investigated with CPS and a microbubble-contrast agent. The perfusion characteristics in the lesions were scored by two investigators and described, and the lesions were measured.

RESULTS

In the seven patients treated with cryoablation for small renal tumours, eight CPS studies were performed. Five lesions showed no enhancement and one lesion, investigated 18 months after treatment was not recognized. In one patient, no enhancement was seen after 1 month but 7 months later, there were minimal contrast signals inside the treated area. The lesions could be measured with a mean standard deviation of 1.1 mm and a mean difference between the two investigators of 0.7 mm.

CONCLUSION

Our first experiences with CPS imaging for the follow-up of renal cryoablation show that this technique can be used to characterize perfusion defects at different times after cryoablation.

Renal Mass Core Biopsy: Accuracy and Impact on Clinical Management

OBJECTIVE

The objective of our study was to determine the accuracy of imaging-guided percutaneous renal mass biopsy and its impact on clinical management.

MATERIALS AND METHODS

With institutional review board approval, we retrospectively reviewed imaging-guided renal biopsies performed by radiologists at our institution between February 1999 and July 2005. Patient records, pathology reports, and imaging studies were reviewed. Concordance of biopsy diagnosis and follow-up data was assessed. Significant impact on clinical management was determined in collaboration with two experienced urologists and was defined as a change from no therapy to therapy, including surgery, tumor ablation, chemotherapy, or radiation.

RESULTS

Two hundred seventy-six renal biopsies were performed during the study period. Of these, 123 were random biopsies and fine-needle technique was used for one; these 124 were excluded. One hundred fifty-two renal mass biopsies were performed using coaxial 18-gauge core needle technique in 125 patients (55 women, 70 men; average age, 60 years; range, 28-90 years). There were two (1.3%) postprocedural hematomas (one [0.7%] requiring blood transfusion) and one (0.7%) delayed renal pseudoaneurysm attributed to biopsy. No tumor seeding was identified. In 85 biopsies (56%), malignant neoplasm was found, 61 biopsies (40%) yielded benign findings, and six (4%) were nondiagnostic. The sensitivity for malignancy was 97.7%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 100%. At least 92 (60.5%) biopsy results significantly impacted clinical management.

CONCLUSION

Imaging-guided percutaneous core needle biopsy of renal masses is safe and highly accurate. Tissue diagnosis alters clinical decision making in a majority of the cases and may allow a number of unnecessary nephrectomies to be avoided.

Renal Masses in the Adult Patient: The Role of Percutaneous Biopsy

Although percutaneous renal mass biopsy with cross-sectional imaging guidance has long been considered to be safe and accurate, there have been recent advances in imaging, interventional, and cytologic techniques that have increased the role of percutaneous biopsy in the diagnosis of renal masses. Today, biopsy plays a fundamental role in the care of patients with a renal mass. Biopsy results are used to confirm the diagnosis of renal cancers, metastases, and infections, and there is increasing evidence to suggest that biopsy can help subtype and grade many primary renal cancers. Because a considerable fraction of small solid renal masses are benign and do not need treatment, there is an increasing need to diagnose them. Biopsy after a full imaging work-up can help prevent unnecessary and potentially morbid surgical and ablation procedures in a substantial number of patients. Although more data are needed to understand the overall accuracy of biopsy for the diagnosis of benign lesions, many can be diagnosed with the aid of biopsy findings. This article reviews reported experience with percutaneous renal mass biopsy, discusses the technical factors that contribute to results, and details seven specific clinical settings that should prompt the clinician to consider percutaneous biopsy when encountering a renal mass.

The Use of MN/CA9 Gene Expression in Identifying Malignant Solid Renal Tumors

OBJECTIVE

Small solid renal tumors are increasingly encountered. It is important to determine the malignancy of solid renal tumors for the choice of treatment. MN/CA9 is expressed in malignant renal cells but absent in normal cells. MN/CA9 is one of the most powerful gene markers available for RCC. The objective of this pilot study is to utilize MN/CA9 gene expression in FNA biopsy to determine the malignancy of imaging-indeterminate solid renal tumors.

METHODS

A total of 35 patients with an imaging-indeterminate solid renal mass entered into this study. The molecular protocol consisted of a rapid column extraction of RNA and one-step RT-PCR for the detection of MN/CA9 gene expression. The preoperative molecular diagnosis was compared with postoperative pathology.

RESULTS

There were 28 RCCs (19 clear cell carcinomas, 7 papillary carcinomas and 2 chromophobe carcinomas) and 7 benign tumors proved by postoperative pathology. The overall sensitivity and specificity for MN/CA9 were respectively 68% and 100%. MN/CA9 was positive in 16/19 (84%) FNA biopsies of clear cell RCCs. No false positive appeared for MN/CA9 gene expression. Moreover, MN/CA9 gene expression was positive in 8/13 (62%) of false negative or suspect cytology.

CONCLUSION

Detection of MN/CA9 gene expression in FNA biopsy is possible. Its detection can be helpful in identifying the malignancy among renal tumors.

Renal oncocytoma: a clinicopathological analysis of 45 consecutive cases

OBJECTIVE

To evaluate the clinical behaviour and pathology of renal oncocytoma in a well-defined population over a 30-year period.

PATIENTS AND METHODS

In a retrospective population-based study we assessed relevant clinical and pathological factors in 45 patients (31 men and 14 women) diagnosed with renal oncocytoma in Iceland between 1971 and 2000. Clinical presentation, pathology, survival and causes of death were evaluated.

RESULTS

The age-standardized incidence was 0.3 per 100,000 per year for both men and women, the incidence of oncocytomas being 5.5% of renal cell carcinomas (RCCs) diagnosed during the same period in Iceland. Fourteen patients were diagnosed at autopsy for an unrelated disease. Of 31 living patients (mean age 70.5 years), seven were diagnosed incidentally (23%), and the others had presented with haematuria (32%), abdominal pain (29%), and weight loss (10%). All the patients had a radical nephrectomy, except for one with bilateral oncocytoma who had a partial nephrectomy. The mean (range) tumour size was 5.7 (0.9-12) cm. Eighteen patients (58%) were diagnosed at Tumour-Node-Metastasis stage I, 10 at stage II (32%) and three at stage III (10%), all of those at stage III having renal capsular penetration or tumour invasion into perirenal fat tissue (T3aN0M0). No patients were diagnosed with lymph node or distant metastasis. Two cases of coexisting RCC were detected. After a median follow-up of 8.3 years there were no recurrences or deaths from oncocytoma (100% disease-specific survival). The overall 5-year survival was 63%, with most patients dying from cardiovascular diseases or nonrenal cancers.

CONCLUSIONS

In most cases renal oncocytoma behaves like a benign tumour; the long-term prognosis is excellent. Thus, in the present patients, radical nephrectomy could be regarded as an over-treatment and nephron-sparing surgery as more appropriate, especially in patients with small tumours. However, both coexisting RCC and perirenal fat invasion, a hallmark of malignant behaviour, might indicate that more radical surgery is warranted in some of these patients.

2-Deoxy-2-[F-18]fluoro-D-glucose-Positron Emission Tomography in Characterization of Solid Renal Masses

The present study was aimed to evaluate the ability of 2-deoxy-2-[F-18]fluoro-D -glucose (FDG)-positron emission tomography (PET) in characterization of solid renal masses visualized by computed tomography (CT)/magnetic resonance imaging (MRI) in patients with suspected or known malignancies.

METHODS

Twenty-eight solid renal masses (20 unilateral and four bilateral, Size ranges, 1.0-8.4 cm) were evaluated in 24 patients. The results were correlated with histopathology in 15 patients, and clinical follow-up and conventional imaging in all patients.

RESULTS

Of the 28 solid renal masses, 10 were primary (nine malignant, one benign) and 18 were metastatic renal tumors. FDG-PET accurately depicted 23 of 27 (85%) malignant renal masses. Of the 10 primary renal tumors, FDG-PET was true positive in eight of nine (89%), true negative in one and false negative in one. The maximum and average standardized uptake values (SUVs) for FDG positive primary renal malignant tumors were 7.9 +/- 4.9 and 6.0 +/- 3.6, respectively. In addition to the characterization of primary tumors, FDG-PET was valuable in primary staging and altered treatment in 30% of patients (three of 10). Of the 18 metastatic renal masses, FDG-PET was positive in 15 (83%) masses. The maximum and average SUVs of metastatic renal masses were 6.1+/- 3.4 and 4.7+/- 2.8, respectively. There was no significant difference in maximum and average SUVs between primary and metastatic renal masses (p=0.3 and p=0.3).

CONCLUSION

Despite the physiological excretion of FDG by the kidneys, FDG-PET can be employed effectively in characterization of solid renal masses in patients with suspected or known malignancies. We propose that FDG-PET could be useful as a complimentary modality to conventional imaging in these patients.

Short-term efficacy of temperature-based radiofrequency ablation of small renal tumors

OBJECTIVES

To present our experience using radiofrequency ablation (RFA) for the treatment of small renal tumors. Our objective was to assess the short-term (1 to 3 years) oncologic efficacy of RFA.

METHODS

Consecutive renal tumors treated since May 2001 with a minimal follow-up of 6 months were included. Patients were treated with a temperature-based radiofrequency generator and were followed up with serial imaging at 6 weeks, 3 and 6 months, and every 6 months thereafter.

RESULTS

A total of 109 small renal tumors (91 patients) were treated with computed tomography-guided percutaneous RFA (n = 63) or laparoscopic RFA (n = 46). The mean tumor size was 2.4 cm (range 0.8 to 4.7). The initial ablation was successful in 107 (98%) of 109 tumors. The two incomplete ablations were successfully re-ablated. Of the 60 patients with at least 1 year of follow-up, 60% had biopsy proven renal cell carcinoma (an additional 24% had no tissue diagnosis). In this group, one local recurrence (1.7%) was detected during a mean follow-up of 19.4 months (range 12 to 33), and in those with known renal cell carcinoma, none had evidence of distant progression (0%). The local recurrence was successfully re-ablated such that all 109 cases had no clinical or radiographic evidence of disease at last follow-up. Three patients died of causes unrelated to cancer.

CONCLUSIONS

The results of our study have shown that in the short term, RFA appears to be a reasonable therapeutic nephron-sparing approach for treating select patients with small renal tumors. The cancer control appears adequate to date, but longer follow-up is necessary before widespread application.

Characteristics of image-detected solid renal masses: Implication for optimal treatment

BACKGROUND

Solid renal masses are found increasingly. Further analysis of the characteristics of solid renal masses is useful for optimal treatment.

METHODS

A retrospective analysis of all solid renal masses was conducted from December 1998 to May 2003 at the Urology Department, Central University Hospital of Saint-Etienne, France. A total of 162 solid renal masses were treated. The preoperative imaging diagnosis of ultrasound and computed tomography, and final pathological results were reviewed.

RESULTS

One hundred and forty-five tumors were pathologically confirmed to be renal cell carcinomas (RCC); 17 tumors (10.5%) were benign. There were eight renal oncocytomas, eight renal angiomyolipomas and one benign mixed epithelial/stroma tumor. Three oncocytomas and five angiomyolipomas were strongly suspected before surgery. The majority of the benign tumors were < or =4 cm. The percentage of small benign tumors (< or =4 cm) was significantly higher than large benign tumors (>4 cm). Although it is possible to use imaging to detect some benign tumors, the majority of benign tumors cannot be diagnosed definitively by imaging before surgery.

CONCLUSIONS

Malignancy in solid renal masses is tumor-size related. Benign solid renal tumors appear mainly as small-sized tumors. The preoperative differentiation between an RCC and a benign tumor can be difficult. Our data suggest that a biopsy is necessary in selected patients to achieve the maximum accuracy in order to provide optimal treatment.

Evaluation of sonographically guided percutaneous core biopsy of renal masses

OBJECTIVE

Our objective was to determine the utility of sonographically guided percutaneous core biopsy to evaluate renal masses.

MATERIALS AND METHODS

We conducted a retrospective analysis of our imaging-guided procedures from January 1999 to June 2001. We performed 26 sonographically guided percutaneous core biopsies of renal masses in 26 patients. From two to five specimens were obtained from a single mass in each patient using an 18-gauge automated biopsy system. We examined the patients' medical records, pathology results, and imaging studies. Core biopsy results were compared with surgical pathology (n = 6) or clinical follow-up (n = 20).

RESULTS

All biopsies provided sufficient material for analysis. Biopsy findings were positive for malignancy in 19 (73%) of 26 masses. Histologic diagnoses included renal cell carcinoma were (n = 11), metastasis (n = 3), lymphoma (n = 2), and transitional cell carcinoma (n = 2). Specific cell type characterization could not be made on one biopsy, but the specimens were highly suspicious for malignancy. Biopsy revealed seven (27%) of 26 benign diagnoses: oncocytoma (n = 3), angiomyolipoma (n = 2), and fibrosis (n = 2). The average follow-up period for patients with benign diagnoses was 10 months. One case of surgically proven necrotic pyelonephritis was mischaracterized as fibrosis at core biopsy. Sonographically guided percutaneous core biopsy of renal masses showed a sensitivity of 100% and a specificity of 100% for the diagnosis of malignancy. The core specimens yielded a specific diagnosis in 92% (24/26) of masses. No immediate complications occurred after the procedure. One patient developed a pseudoaneurysm that presented 3 months after the biopsy. CONCLUSION. Sonographically guided percutaneous core biopsy is a reliable and accurate method for evaluating renal masses.