Aetiology of non-diagnostic renal fine-needle aspiration cytologies in a contemporary series

Implication of cystic fluid cytology of renal cell carcinoma on surgical practice

OBJECTIVES

To evaluate the incidence of positive cystic fluid cytology and its risk factors in cystic renal cell carcinoma (RCC) addressing its implication on the current surgical practice.

METHODS

All clinically diagnosed Bosniak III, IV cystic renal masses from March 2019 to August 2022 were studied prospectively. Database of patients' demographics and cystic tumor characteristics were recorded. Partial or radical nephrectomies were performed by either laparoscopic or robotic approach. Cystic fluid was collected right after specimen retrieval in the surgical field and examined by pathologist. Cytology results were compared to the demographic, perioperative variables using univariate and multivariate analysis.

RESULTS

A total of 70 patients of histologically confirmed cystic RCC were included. Sixty seven patients underwent radical nephrectomy with laparoscopic or robotic approaches, while 3 patients underwent radical nephrectomy. There was no intraoperative cystic rupture or fluid spillage. Positive cystic fluid cytology findings were identified in 34 (48.6%) patients, while negative cystic fluid cytology were identified in 36 (51.4%) cases. Definite malignant cells were observed in 28 patients while the other six patients showed highly suspicious atypical cells. Histologically, 24 (70.8%) patients were proven clear cell RCC and 25 (73%) showed Fuhrman grade 1 or 2 in final histologic review in positive group. Univariate and multivariate regression analysis between positive and negative cytology groups showed that the presence of the malignant cells in cystic fluid was significantly associated with patients' age (> 55 years) and Bosniak grade of cystic tumor (p < 0.05).

CONCLUSIONS

Definite malignant cells in cystic fluid cytology were observed through our study. Additionally, patients' age (> 55 years) and Bosniak grade were the significant risk factors of positive cytology in cystic RCC. Therefore, necessity of meticulous manipulation of cystic renal tumors, despite their clinical features, should not be underemphasized to avoid the least possible tumor cell seeding in case of cystic rupture when operating such high risk of positive cytology.

Nondestructive Diagnosis of Kidney Cancer on 18-gauge Core Needle Renal Biopsy Using Dual-color Fluorescence Structured Illumination Microscopy

OBJECTIVE

To present a novel imaging technique used for rapid, nondestructive histological assessment of renal neoplasias using a dual-component fluorescence stain and structured illumination microscopy (SIM).

MATERIALS AND METHODS

After Institutional Review Board approval, 65 total biopsies were obtained from 19 patients undergoing partial or radical nephrectomy. Biopsies were stained with a dual-component fluorescent, and optically sectioned SIM images were obtained from the surface of the intact biopsies. Specimens were subsequently fixed and analyzed using hematoxylin and eosin (H&E) histopathologic methods and compared with SIM images. A single, board-certified pathologist blinded to specimens reviewed all SIM images and H&E slides, and determined the presence or absence of neoplasias. Results of blinded diagnosis of SIM were validated against traditional pathology.

RESULTS

Of the 19 patients, 15 underwent robotic partial nephrectomies and 4 underwent laparoscopic nephrectomies. Indications included clinical suspicion of renal cell carcinoma. In total, 65 biopsy specimens were available for review. Twenty-one specimens were determined to be neoplastic on H&E, whereas 41 represented benign renal tissue. The final sensitivity and specificity of our study were 79.2% and 95.1%, respectively.

CONCLUSION

SIM is a promising technology for rapid, near-patient, ex vivo renal biopsy assessment. By improving the ability to rapidly assess sufficiency of biopsy specimens and enabling immediate diagnostic capability, SIM aids in more effective biopsy performance, tissue triage, and patient counseling regarding management options. Additionally, because tissue is preserved, effective utilization of downstream diagnostic tests and molecular assessments are possible.

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.

On-site adequacy evaluations performed by cytotechnologists: correlation with final interpretations of 5241 image-guided fine-needle aspiration biopsies

BACKGROUND

Practice patterns regarding on-site assessment of the adequacy of image-guided fine-needle aspiration biopsies (FNABs) vary among laboratories, but in many laboratories primary responsibility rests with the cytotechnologists. On-site evaluation provides feedback on the need for additional passes and facilitates triaging of the specimen for time-sensitive ancillary studies. Prior studies have suggested that cytotechnologists can assess the initially obtained specimens correctly, but they are few in number and limited by small size. The purpose of this study was to assess the frequency with which our cytotechnologists were able to correctly assess specimens as adequate using a large-scale database that included a wide range of image-guided FNABs.

METHODS

The frequency that on-site adequacy assessments of 5241 image-guided FNABs were correct was determined by correlating the cytotechnologists' assessments of adequacy with the final cytologic interpretation. An adequacy assessment was considered correct if the FNAB was ultimately reported as satisfactory and unequivocally benign or malignant. An adequate reading on a case that was ultimately reported as unsatisfactory, atypical, or suspicious was deemed "incorrect." The effect of imaging modality was also analyzed.

RESULTS

Of 5241 FNABs, 2784 (53%) were interpreted as adequate on site. Of these, 2637 (95%) were correctly considered adequate. Of the common biopsy sites sampled, the adequacy assessments for liver FNABs demonstrated the highest frequency for being correctly considered adequate (97%) and those for kidney FNABs showed the lowest (90%). Imaging modality had no effect on accuracy.

CONCLUSIONS

Cytotechnologists are almost always correct when assessing initial FNAB samples as adequate.

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.