Solid renal masses in adults: Image-guided fine-needle aspiration cytology and imaging techniques—“Two Heads Better Than One?”

A systematic review on performance characteristics of FNA of renal lesions: It is time for a standardized classification system

BACKGROUND

The incidence of renal tumors has steadily increased over the past decade. In this study, the authors performed a systematic review and analysis of the literature on renal fine-needle aspiration (FNA) to determine its performance and explore whether a standardized classification system can be used for reporting renal FNA cytology.

METHODS

A systematic search of published articles on renal FNA was conducted. The data on FNA and histologic diagnosis were extracted and categorized, and the risk of malignancy was calculated. Different scenarios were used to estimate FNA performance statistics.

RESULTS

Of the 3766 potentially relevant studies, 23 met the inclusion criteria of the study. The 2231 FNA cases included were re-categorized according to the classification system, rendering 142 (6.36%) nondiagnostic, 270 (12.1%) nonneoplastic, 271 (12.14%) benign neoplasm, 65 (2.91%) renal neoplasm with unknown malignant potential, oncocytic type, 25 (1.12%) atypia of undetermined significance, 60 (2.68%) suspicious for malignancy, and 1398 (62.66%) malignant FNA diagnoses. The risk of malignancy in these cases was 65.4%, 18.1%, 16.6%, 16.9%, 60%, 73.3%, and 96.9%, respectively. According to the classification system, the study indicated that the accuracy of renal FNA was between 91% and 95%, the sensitivity was 90.9%-96.7%, and the specificity was 82%-92% in different scenarios.

CONCLUSIONS

There is a need for a standardized reporting in renal cytology that will improve the sensitivity and accuracy of renal cytology, reduce the rate of indeterminate diagnoses, and alter the management strategies of renal lesions. Based on the available literature, a new reporting system is proposed, including categories with an associated risk of malignancy.

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.

Indications for renal fine needle aspiration biopsy in the era of modern imaging modalities

Background:

Renal fine needle aspiration biopsy (FNAB) has become an uncommon procedure in the era of renal helical computed tomography (CT), which has high diagnostic accuracy in the characterization of renal cortical lesions. This study investigates the current indications for renal FNAB. Having knowledge of the specific clinico-radiologic scenario that led to the FNAB, cytopathologists are better equipped to expand or narrow down their differential diagnosis.

Materials and Methods:

All renal FNABs performed during a 6 year interval were retrieved. Indication for the procedure was determined from the clinical notes and radiology reports.

Results:

Forty six renal FNABs were retrieved from 43 patients (14 females and 29 males with a mean age of 52 years [range, 4-81 years]). Twenty one cases (45.6%) were performed under CT-guidance and 25 cases (54.4%) under US-guidance. There were four distinct indications for renal FNAB: (1) solid renal masses with atypical radiological features or poorly characterized on imaging studies due to lack of intravenous contrast or body habitus (30.2%); (2) confirmation of radiologically suspected renal cell carcinoma in inoperable patients (advanced stage disease or poor surgical candidate status) (27.9%); (3) kidney mass in a patient with a prior history of other malignancy (27.9%); and (4) miscellaneous (drainage of abscess, indeterminate cystic lesion, urothelial carcinoma) (14.0%). 36 patients (83.7%) received a specific diagnosis based on renal FNAB cytology.

Conclusions:

Currently, renal fine needle aspiration remains a useful diagnostic tool in selected clinico-radiologic scenarios.

Feasibility of differential diagnosis of kidney tumors by comparative genomic hybridization of fine needle aspiration biopsies

The association of a genetic analysis that could improve the diagnostic accuracy of renal cell tumors in biopsy samples would allow better-informed therapeutic decisions. We performed comparative genomic hybridization (CGH) on an ex vivo fine-needle aspiration (FNA) biopsy and a tumor fragment obtained from 75 patients consecutively diagnosed with renal tumors and subjected to radical nephrectomy. The pattern of genomic changes by CGH was used blindly to classify the renal tumors and the genetic findings were subsequently compared with the histopathologic diagnosis. In particular cases, including in two carcinomas with morphologically distinct tumor areas, we performed FISH with several locus-specific probes, and looked for VHL point mutations, exonic rearrangements, or promoter methylation. CGH was successful in 82.7% FNA biopsies and in 96% tumor fragments, with the former allowing genetic diagnosis in 75% of renal cell tumors. The genetic and the initial histological classification differed in two renal neoplasias, but the genetic diagnosis was confirmed after review. The genetic pattern correctly diagnosed 93.5% of clear cell renal cell carcinomas (RCC), 61.5% of chromophobe RCC, 100% of papillary RCC, and 14.3% of oncocytomas, with the negative predictive value being 93.9, 90.7, 100, and 90.2%, respectively. The positive predictive value and specificity of copy number profiles was 100%. We demonstrate that genetic diagnosis by CGH on FNA biopsies can improve differential diagnosis in patients with kidney tumors.

Renal mass sampling: an enlightened perspective

Renal mass sampling (RMS) can be carried out by core biopsy or fine needle aspiration with each presenting potential advantages and limitations. The literature about RMS is confounded by a lack of standardized techniques, ambiguous terminology, imprecise definitions of accuracy, substantial rates of non-informative biopsies, and recurrent diagnostic challenges with respect to eosinophilic neoplasms. Despite these concerns, RMS has an expanding role in the evaluation and treatment of renal masses, in order to stratify biological aggressiveness and guide management that can range from surgery to active surveillance. Non-informative biopsies can be managed with surgical excision or repeat biopsy, with the latter showing encouraging results in recent studies. We propose a new classification in which all biopsies are categorized as non-informative versus informative, with the latter being subclassified as confirmed accurate, presumed accurate or confirmed inaccurate. This terminology will facilitate the comparison of results from various studies and stimulate progress. Incorporation of novel biomarkers and molecular fingerprinting into RMS protocols will likely allow for more rational management of patients with renal masses in the near future.

Biopsy of a renal mass: where are we now?

PURPOSE OF REVIEW

To review the most recent literature concerning renal mass biopsy with special consideration to three points: variation in results related to the standard used as comparison, biopsy in small renal masses (up to 4 cm in diameter) and the case for nondiagnostic biopsy.

RECENT FINDINGS

The overall rate of failed and indeterminate biopsies shows a trend for improvement. However, selection bias and the lack of a uniform index test for comparison preclude a definitive statement. Fine-needle aspiration may equal results of core biopsy, but its role in the diagnostic algorithm is not yet defined. In-vivo accuracy decreases in small renal masses with the same limitations exposed for the overall literature on renal mass biopsy. When nondiagnostic biopsies are considered, there is a need for standardization of the nomenclature in order to compare results. Re-biopsies or surgery after a nondiagnostic biopsy shows malignancy in up to 75% of the cases of renal cell carcinoma.

SUMMARY

There is a trend in increasing interest and accuracy on the subject of percutaneous biopsy of renal masses as well as a decreasing trend in the rate of nondiagnostic biopsies. In the small renal masses, most likely to be benign, a diagnostic percutaneous biopsy may have a definitive role. However, the higher rate of nondiagnostic results in this population calls for prospective studies with standard definitions and when possible homogenous index test to properly assess the diagnostic performance of the biopsy.