Utility of the Proposed Sydney System for Classification of Fine-Needle Aspiration Cytopathology of Lymph Node: A Retrospective Study at a Tertiary Care Center

INTRODUCTION

Fine-needle aspiration cytology (FNAC) is an established first-line technique for the evaluation of lymphadenopathy and, with the help of ancillary testing, can in many instances obviate the need for an open biopsy. The Sydney system was recently proposed to provide consensus guidelines for the performance, classification, and reporting of lymph node FNAC. The present study was undertaken to evaluate its utility and study the impact of rapid on-site evaluation (ROSE).

MATERIAL AND METHODS

A retrospective analysis in which 1,500 lymph node FNACs was reviewed and assigned a diagnostic category from the Sydney system. Cyto-histopathological correlation and adequacy parameters were evaluated.

OBSERVATION AND RESULTS

The cervical group of lymph nodes was the commonest group aspirated (89.7%). A total of 1,205/1,500 (80.3%) cases were category II (benign), and necrotizing granulomatous lymphadenitis was the most common pathology. The 750 cases with ROSE were subclassified as follows: 15 category I (inadequate), 629 category II (benign), 2 category III (atypia of undetermined significance), 9 category IV (suspicious for malignancy), and 95 category V (malignant). Among 750 cases without ROSE, 75 cases were in category I, 576 in category II, 3 in category III, 6 in category IV, and 90 in category V. Category I was thus significantly lower in the ROSE group compared to the non-ROSE group. Overall, the risk of malignancy was L1-0%, L2-0.20%, L3-100%, L4-92.3%, and L5-100%. Accuracy parameters revealed a sensitivity of 97.7%, specificity of 100%, PPV of 100%, NPV of 99.10%, and diagnostic accuracy of 99.54%.

DISCUSSION AND CONCLUSION

FNAC can be used as the 1st line of treatment for lymph node pathology. ROSE can be used as an add-on to FNAC for reducing unsatisfactory rates and help triage material for ancillary testing whenever possible. The Sydney system should be implemented for achieving uniformity and reproducibility.

Utility and Limitations of Fine-Needle Aspiration Cytology in the Diagnosis of Lymphadenopathy

BACKGROUND

Fine needle aspiration cytology (FNAC) is a valuable tool for evaluating lymphadenopathy. The purpose of this study was to assess the reliability and effectiveness of FNAC in the diagnosis of lymphadenopathy.

METHODS

Cytological characteristics were evaluated in 432 patients who underwent lymph node FNAC and follow-up biopsy at the Korea Cancer Center Hospital from January 2015 to December 2019.

RESULTS

Fifteen (3.5%) of the four hundred and thirty-two patients were diagnosed as inadequate by FNAC, with five (33.3%) of these diagnosed as metastatic carcinoma on histological examination. Of the 432 patients, 155 (35.9%) were diagnosed as benign by FNAC, with seven (4.5%) of these diagnosed histologically as metastatic carcinoma. A review of the FNAC slides, however, showed no evidence of cancer cells, suggesting that the negative results may have been due to FNAC sampling errors. An additional five samples regarded as benign on FNAC were diagnosed as non-Hodgkin lymphoma (NHL) by histological examination. Of the 432 patients, 223 (51.6%) were cytologically diagnosed as malignant, with 20 (9.0%) of these diagnosed as tissue insufficient for diagnosis (TIFD) or benign on histological examination. A review of the FNAC slides of these 20 patients, however, showed that 17 (85.0%) were positive for malignant cells. The sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV), and accuracy of FNAC were 97.8%, 97.5%, 98.7%, 96.0%, and 97.7%, respectively.

CONCLUSIONS

Preoperative FNAC was safe, practical, and effective in the early diagnosis of lymphadenopathy. This method, however, had limitations in some diagnoses, suggesting that additional attempts may be required according to the clinical situation.

[New aspects in fine needle biopsies of the lymph nodes]

BACKGROUND

The cytology of lymph nodes is a cost-effective method with a short turnaround time and low risk to patients that delivers valuable information on the cause of the lymphadenopathies.

OBJECTIVES

To discuss the value of lymph node cytology in the diagnosis of lymph node swellings.

METHODS

Analysis of the causes of the controversially discussed aspects of lymph node cytology. Presentation of the diagnostic groups of lymph node cytology according to the Sydney system.

RESULTS

The technical aspects of lymph node sampling during fine needle biopsy, as well as the subsequent preparation of the correctly fixed direct smears and the triage of the sample for the auxiliary studies, may pose a significant challenge for some puncturers. The whole spectrum of modern pathologic auxiliary studies can be applied to correctly triaged cytologic samples. The diagnoses of fine needle biopsies of the lymph nodes can be divided into five groups according to the recently proposed Sydney reporting system: insufficient/non-diagnostic, benign, atypical, suspicious, and malignant. Further details concerning the diagnosis as well as recommendations on how to proceed are additionally included in cytologic reports.

CONCLUSIONS

The improvement of lymph node sampling as well as the technical aspects of the sample handling, including the application of auxiliary studies, considerably increase the diagnostic value of fine needle biopsy of the lymph nodes. Wide implementation of the usage of the diagnostic groups for reporting fine needle biopsies of the lymph nodes can standardize reporting and improve communication with other clinical specialists.

Diagnostic accuracy of Thinprep® in cervical lymph node aspiration: Assessment according to the Sydney system

BACKGROUND

Fine-needle aspiration cytology (FNAC) is a reliable technique that has been used for many years in lymphadenopathy diagnosis. Although conventional smear is the standard approach in FNAC, liquid-based cytology (LBC) is accepted as an alternative method. Reporting standardization is a significant gap in fine-needle aspiration cytology, leading to failure in pathologist-clinician dialog and interobserver variability. In 2020, an expert panel proposed the Sydney system for classifying and reporting lymph node aspiration cytology. This study aimed to evaluate the diagnostic accuracy of LBC in lymph node aspiration cytology under the guidance of the Sydney system.

METHODS

Five hundred-four LBC samples were reevaluated and classified according to the Sydney system. Of these, n = 24 were categorized as L1-inadequate/non-diagnostic, n = 283 as L2-benign, n = 36 as L3- atypical cells of undetermined significance/atypical lymphoid cells of uncertain significance (AUS/ALUS), n = 48 as L4-suspicious, and n = 113 as L5-malignant. Four hundred-one samples were histopathologically confirmed. The diagnostic accuracy of LBC and the risk of malignancy for each Sydney category were calculated.

RESULTS

The results were as follows: sensitivity 98.97%; specificity 98.60%; positive predictive value 94.80%; negative predictive value 99.29%; and overall diagnostic accuracy 98.75%. The ROM was 16.6% for L1, 0.7% for L2, 88.8% for L3, and 100% for L4 and L5.

CONCLUSION

LBC is suitable for use in lymph node aspiration under the guidance of the Sydney system and has high diagnostic accuracy. Future comprehensive studies will increase the applicability of the Sydney system and minimize interobserver variability.

Assessment of risk of malignancy by application of the proposed Sydney system for classification and reporting lymph node cytopathology

BACKGROUND

Fine-needle aspiration cytology (FNAC) is one of the most commonly used techniques for evaluating lymphadenopathy. Recently, the Sydney system was proposed for assessing the performance, classification, and reporting of lymph node (LN) cytopathology. The present study was conducted to assess the risk of malignancy associated with each of the diagnostic categories of the proposed Sydney system.

METHODS

This was a 2-year retrospective study of LN-FNAs; cytologic diagnoses were categorized by the proposed Sydney system. Cytological diagnoses were correlated with the corresponding histopathological diagnoses to assess diagnostic accuracy and risk of malignancy for each diagnostic category.

RESULTS

Of 23,335 FNAs during the study period, 6983 (30%) were performed on LNs. Of these, 289 (4.1%) cases were reported as nondiagnostic/inadequate (L1); 3397 (48.6%) were reported as benign (L2); 33(0.5%) as atypical cells of undetermined significance (L3), 96 (1.4%) as suspicious for malignancy (L4) and 3168 (45.4%) as malignant (L5). Subsequent histopathology was available for 618 (8.8%) cases. On cytohistopathologic correlation, 552 (89.3%) were concordant and 66 (10.7%) discordant. The overall sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of LN-FNA were 79.9%, 98.7%, 98.4%, 83.1%, and 89.3%, respectively. The risk of malignancy was 27.5% for the nondiagnostic category, 11.5% for the benign, 66.7% for the atypical, 88% for the suspicious, and 99.6% for the malignant categories.

CONCLUSIONS

FNAC has high diagnostic accuracy for the diagnosis of various LN pathologies. Application of the proposed Sydney system can help in achieving uniformity and reproducibility in cytologic diagnoses and also help in risk-stratification on cytology.