Is it time to develop a tiered classification scheme for salivary gland fine-needle aspiration specimens?

Salivary Gland Fine-Needle Aspiration: The Current and Future Landscape

Fine-needle aspiration represents a valid tool for the diagnosis/management of salivary gland lesions. The past years assessed the lack of uniform diagnostic reports for salivary cytopathology leading to interpretative issues. In 2015, an international group of cytopathologists developed an evidence-based tiered classification system for reporting salivary gland fine-needle aspiration (FNA) specimens, the "Milan System for Reporting Salivary Gland Cytopathology" (MSRSGC). The present landscape of salivary cytology is represented by the growing adoption of the MSRSGC and the assessment of its diagnostic role. The future landscape is characterized by the increasing role of ancillary techniques for diagnostic and prognostic purposes.

Implementation of the Milan System for Reporting Salivary Gland Cytology: A Two-Year Outcome Cytopathology Data of a Tertiary Care Center

OBJECTIVE

In 2015, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was implemented to eliminate overlapping and disparate morphologies in salivary gland lesions. This approach helps track diagnostic findings, describe the risk of malignancy for each group, and advance therapy based on the results. The research aimed to classify fine-needle aspiration (FNA) smears, analyze malignancy risk, correlate cytology with histological diagnosis, and reduce unnecessary surgeries.

METHODOLOGY

We evaluated 217 individuals using FNA, classified their conditions using the Milan System, and followed up on 149 cases through histopathology. Both the risk of malignancy in each cluster and the total risk of malignancy were noted.

RESULTS

The most recent studies, as reported by the MSRSGC, found almost universal agreement about this grouping. The FNA cytopathology test demonstrated a sensitivity of 75% for identifying salivary gland abnormalities and a specificity of 93.16%. The findings indicated that the test had an accuracy of 89.66%, with a positive predictive value of 72.41% and a negative predictive value of 93.97%.

CONCLUSION

The MSRSGC offers a standardized technique for examining the results and assists the physician in determining the treatment plan that will be most beneficial.

Assessment of Risk of Malignancy of Fine-needle Aspiration Cytology in Salivary Gland Lesions Using the Milan System for Reporting Salivary Gland Cytopathology Categorization: A Systematic Review and Meta-analysis

BACKGROUND

Fine-needle aspiration cytology (FNAC) of the salivary gland is crucial in the identification of salivary gland lesions, but the variation in morphological pattern and the overlap of morphological traits can result in erroneous interpretation and affect treatment, making FNAC of the salivary gland problematic. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was created to address these problems.

OBJECTIVES

To ascertain whether the FNAC method using MSRSGC was reliable in predicting the risk of malignancy (ROM) in each category of salivary gland lesions.

MATERIALS AND METHODS

The databases PubMed-MEDLINE, Web of Science, Cochrane, Scopus, and Google Scholar were all searched using pertinent keywords, reference searches, and citation searches. A fixed effect model was used to determine the pooled proportion with a 95% confidence interval (CI). All statistical analyses were performed using Meta Disc and R version 4.0.2 (R Foundation for Statistical Computing).

RESULTS

After reviewing the submissions' abstracts and titles, 58 documents that satisfied the necessary inclusion and exclusion criteria were ultimately selected. A total of 19,652 samples from 19,408 individuals was analyzed, out of which 9,958 samples were available for histopathological follow-up. The pooled ROM for category I was 10%, category II was 5%, category III was 28%, category IV A was 2%, Category IV B was 34%, category V was 91%, and category VI was 99%.

CONCLUSION

Milan System for Reporting Salivary Gland Cytopathology is useful for risk stratification and quality control, confirming its validity and diagnostic utility. Widespread use of MSRSGC would improve the accuracy of salivary gland cytology and lead to better patient care and improved treatment strategies. The results of this study are in consonance with reported values as per MSRSGC except for category V.

CLINICAL SIGNIFICANCE

The MSRSGC which was first reported in 2018 is a very useful tool for proper stratification of ROM in salivary gland FNAC. This study allowed us to validate the ROM values in different categories as reported in MSRSGC.

Clinical outcomes and cost-effectiveness of superficial parotidectomy versus extracapsular dissection of the parotid gland: a single-centre retrospective study of 161 patients

Improvements in preoperative diagnostics and intraoperative techniques have made the surgical excision of benign parotid gland tumours less invasive. Extracapsular dissection (ECD) has become more popular in comparison to superficial parotidectomy (SP), the gold standard. Although clinical outcomes have been reported, reports on cost-effectiveness are limited. The aim of this retrospective study was to analyse the surgical outcomes and cost-effectiveness of ECD versus SP in benign parotid tumour surgery. A retrospective cohort of 161 patients treated between 2012 and 2020 was collected. Data concerning demographics, clinical outcomes, and cost-efficiency were recorded. Analysis of the 161 unilateral parotidectomy cases (59 SP, 102 ECD) showed a significantly longer operation time, anaesthesia time, and length of stay for SP patients (all P < 0.001). Regarding postoperative complications, transient facial nerve weakness (P < 0.001) and haematoma formation (P = 0.016) were more prevalent in the SP patients. The frequency of positive margins was lower for SP (P = 0.037). No case of recurrence was identified with either technique. ECD showed excellent clinical outcomes as well as a reduction in complications when compared to SP. ECD is a viable alternative for superficial benign parotid gland tumours after thorough preoperative clinical, pathological, and radiological examination. The reduction in operation, anaesthesia, and hospitalization times with ECD is likely to result in a gain in cost-effectiveness.

Comparative analysis of inter-observer variability between conventional reporting system of salivary gland cytology with Milan system for reporting salivary gland cytopathology

BACKGROUND

Interpretation of salivary gland cytology often leads to inter-observer variability due to heterogenous and complex nature of these lesions. This creates a dilemma regarding their management by clinicians. Proposal of a universal system of reporting of salivary gland lesions leading to agreement in diagnosis and better understanding among clinicians was the need of the hour. Hence Milan system for reporting salivary gland cytopathology (MSRSGC) was proposed in 2015 by the American society of cytopathology and the International Academy of Cytology. Present study was undertaken to assess inter-observer variability in reporting by conventional system and MSRSGC.

MATERIAL AND METHODS

One hundred and seventy-six cases of salivary gland lesions were subjected to fine needle aspiration cytology. Cases were interpreted by two experienced cytopathologists and were reported by both conventional system and MSRSGC. Histopathological correlation was available in 81 cases.

RESULTS

Inter-observer variability was noted in six cases reported by conventional system and in two cases by MSRSGC. Moreover three cases out six cases had different management protocols while both cases of Milan system for reporting salivary gland cytology had same management. Thirteen cases diagnosed by Milan system and 17 cases diagnosed by conventional system were discordant with histopathological diagnosis.

CONCLUSION

Milan system for reporting salivary gland cytology has an edge over conventional system of reporting as it provides better agreement among cytopathologists and better management guidelines for clinicians with the added advantage of assessment of risk of malignancy.

Interobserver variability between cytopathologists and cytotechnologists upon application and characterization of the indeterminate category in the Milan System for Reporting Salivary Gland Cytopathology

BACKGROUND

The indeterminate categories in the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) are diagnostically challenging because of inherent heterogeneity and complexity, with wide interobserver variability (IOV). Herein, the authors explore the concordance rate (CR) between cytopathologists (CPs) and cytotechnologists (CTs) in interpreting indeterminate salivary gland lesions using the MSRSGC.

METHODS

Between 2011 and 2016, 86 indeterminate fine-needle aspirations had slides available for review, of which 48 had follow-up. Four CPs and 2 CTs performed an independent, blinded review of these slides and categorized them according to the MSRSGC. The CRs between CTs and CPs with the final sign-out cytopathologist (FCP) were assessed, and interobserver agreement was categorized into uniform, majority, divided, minimal, or no agreement.

RESULTS

The overall CR with the FCP ranged from 48.8% to 60.5% for CPs and from 22.1% to 36% for CTs. IOV κ scores for the entire group were 0.314 and, with the FCP as the reference, ranged from 0.403 to 0.539 for CPs and from 0.091 to 0.254 for CTs. Uniform, majority, divided, minimal, and no agreement was noted in 12.8%, 31.4%, 38.4%, 10.5%, and 6.9%, respectively, of all cases and in 16.7%, 35.4%, 31.3%, 8.3%, and 6.3%, respectively, of the cases with follow-up. Diagnostic challenges included distinguishing lymphoma from a reactive process and distinguishing mucin from mucin-like material.

CONCLUSIONS

CPs had modestly higher CRs compared with CTs; and, although the variable CRs highlight indeterminate IOV, the MSRSGC enables reproducibility. Characterizing larger cohorts in the indeterminate categories will further improve MSRSGC criteria. Moreover, education on the MSRSGC should include CTs and CPs to improve overall diagnostic accuracy.

Milan System for Reporting Salivary Gland Cytopathology- An Experience from Western Indian Population

Introduction:

Fine-needle aspiration cytology (FNAC) can be challenging to provide a precise diagnosis in salivary gland cytopathology due to diversity of lesions and cytomorphological convergence between the tumors and within the same tumor of salivary gland. The recently proposed Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) provides a risk stratification-based classification system with an intrinsic risk of malignancy (ROM) for each diagnostic category, which aims to furnish useful information to the clinicians. This study was undertaken to evaluate the diagnostic utility and validity of MSRSGC.

Methods and Material:

In this retrospective study, FNAC done for all salivary gland lesions over a period of two years were retrieved. All cases were categorized according to MSRSGC and correlated with histopathological follow-up, wherever available. ROM was calculated for each category.

Results:

The cases belong to following categories: non-diagnostic (1.27%), non-neoplastic (30.38%), atypia of undetermined significance (5.06%), benign neoplasm (46.84%), salivary gland neoplasm of uncertain malignant potential (1.27%), suspicious for malignancy (1.27%), and malignant (13.92%). Out of 79 cases, 50.63% had follow-up. The ROM were 0% for category II and IVa, 50% for category III, and 100% for category IVb, V, and VI. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were recorded as 77.78%, 100%, 100%, 91.3%, and 93.33%, respectively.

Conclusions:

Application of MSRSGC has immense value for standardization of reporting of salivary gland FNAC. Our data corresponds to the studies done worldwide and recommends the use of MSRSGC for future diagnostic purposes.

The risk for malignancy using the Milan salivary gland classification categories: A 5-year retrospective review

Aims:

Since the six-tier Milan salivary gland classification has been introduced, there are very limited studies in literature reporting the risk stratification of the Milan classification.

Methods:

We retrospectively classified a total of 285 salivary gland cytology cases into Milan reporting categories; there were 23 (8.1%) nondiagnostic, 48 (16.8%) nonneoplastic, 19 (6.7%) atypia of undetermined significance (AUS), 138 (48.4%) benign neoplasm, 13 (4.6%) neoplasm of uncertain malignant potential (NUMP), 8 (2.8%) suspicious for malignancy, and 36 (12.6%) malignant. Almost 110 cases (38.6%) had surgical follow-up resections.

Results:

The overall risk for malignancy (ROM) was 12.5% for AUS, 3.2% for benign neoplasm, 72.7% for NUMP, and 100% for the suspicious for malignancy and malignant. The ROM for nondiagnostic and nonneoplastic categories was not representative due to limited follow-up resections. The salivary cytology had sensitivity, specificity, positive predictive value, and negative predictive value of 93.0%, 100%, 100%, and 46.2% for neoplasm and 82.3%, 95.8%, 90.3%, and 92.0% for malignant.

Conclusion:

Our study supports the adaptation of the six-tier Milan classification for reporting salivary gland cytology, as well as emphasizing the utility of the NUMP category.

Moving toward a systematic approach for reporting salivary gland cytopathology: cytohistological correlation with the application of the Milan system for risk stratification at a tertiary care center

INTRODUCTION

Fine-needle aspiration cytology (FNAC) of salivary glands is a well-established technique that plays a critical role in the preoperative diagnosis of lesions. Despite its clinical utility, it remains one of the most challenging areas in cytopathology. This is because there is no consensus on how to report salivary gland cytopathology, which has resulted in inconsistent terminology and confusion in communication among cytopathologists and clinicians. A risk stratification of FNA diagnostic categories has been recently proposed to be useful in reporting.

MATERIALS AND METHODS

A retrospective study of FNAC of salivary gland lesions reported from 2014 to 2017 was performed. The performance of the cytology reporting system was evaluated with histological diagnosis serving as the gold standard. The aspirates were then categorized according to the Milan system. Furthermore, the risk of malignancy was calculated for all diagnostic categories.

RESULTS

A total of 899 salivary gland aspirates were evaluated: 2.2% were nondiagnostic, 55.8% indicated nonneoplastic lesions, and 40.4% indicated neoplastic lesions. Histopathology was available for 172 cases. FNA had a sensitivity of 72.3% and a specificity of 92.6% with an overall diagnostic accuracy of 91.4% for differentiating malignant from benign tumors.

CONCLUSION

A tiered classification scheme as proposed by the Milan system may prove helpful in effectively guiding clinical management of patients with salivary gland lesions. Our experience with this system helps to pave the way for the adoption of the Milan System for Reporting Salivary Gland Cytopathology.

Risk stratification of fine-needle aspiration cytology of parotid neoplasms based on the Milan system-Experience from a tertiary center in Asia

BACKGROUND

The recently described Milan system provides a unified way of categorizing salivary gland fine-needle aspiration (FNA) cytology. We aim to use this system to stratify risk of malignancy in parotid FNAs.

METHODS

In this retrospective case series, 376 FNAs were preoperatively performed for 573 parotidectomies over 14 years.

RESULTS

Risk of malignancy on FNA is as follows: nondiagnostic 14.5%, non-neoplastic 26.7%, atypia of undetermined significance 29.3%, benign neoplasm 2.7%, neoplasm of uncertain malignant potential 19.1%, suspicious for malignancy 87.5%, and malignant 100%. The specific diagnoses of pleomorphic adenoma and Warthin tumor on FNA have high positive predictive value of 97.5% and 96.6%, respectively. Multivariate regression associates smaller size of lesion with a nondiagnostic or indeterminate result. Seniority of operator is associated with a lower likelihood of a nondiagnostic result.

CONCLUSIONS

This large Asian series validates the Milan system as a valuable tool in stratifying malignancy risk of parotid FNAs.

Salivary Gland Fine Needle Aspiration and Introduction of the Milan Reporting System

Fine needle aspiration (FNA) is a well-established procedure for the diagnosis and management of salivary gland lesions despite challenges imposed by their diversity, complexity, and cytomorphologic overlap. Until recently, the reporting of salivary gland FNA specimens was inconsistent among different institutions throughout the world, leading to diagnostic confusion among pathologists and clinicians. In 2015, an international group of pathologists initiated the development of an evidence-based tiered classification system for reporting salivary gland FNA specimens designated the "Milan System for Reporting Salivary Gland Cytopathology" (MSRSGC) that culminated with the publication of the MSRSGC Atlas in February 2018. The MSRSGC consists of 6 diagnostic categories, which incorporate the morphologic heterogeneity and overlap among various non-neoplastic, benign, and malignant lesions of the salivary glands. In addition, each diagnostic category is associated with a risk of malignancy and management recommendations. The main goal of the MSRSGC is to improve communication between cytopathologists and treating clinicians, while also facilitating cytologic-histologic correlation, sharing of data from different laboratories for quality control, and research. Herein, we review the current status of salivary gland cytology and the role of MSRSGC in providing a framework for reporting salivary gland lesions.

A comparison study of the reporting systems for salivary gland fine needle aspirations: Are they really different?

BACKGROUND

Recently a new system for reporting salivary gland fine-needle aspiration (FNA) cytology was proposed, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC). Herein, we evaluated diagnostic accuracy of salivary gland FNA, comparing the system previously used in our hospital with the Milan system.

METHODS

Salivary gland specimens obtained between 2011 and 2017 were reclassified according to MSRSGC. Risk of malignancy for each diagnostic category was determined. Diagnostic yield of both classifications was evaluated.

RESULTS

The cases (n = 388) were classified according to the old system: nondiagnostic (n = 28), benign (n = 246), atypical (n = 36), neoplastic (n = 57), suspicious for malignancy (n = 7) and malignant (n = 14). The lesions were distributed according to the MSRSGC: nondiagnostic (n = 28), non-neoplastic (n = 89), atypia of undetermined significance (n = 39), benign neoplasm (n = 156), neoplasm of uncertain malignant potential (n = 55), suspicious for malignancy (n = 7) and malignant (n = 14). When considering only benign and malignant cases, both classifications showed the same sensitivity (62.5%), specificity (100%) and similar accuracy (95.8%). Comparison between the two systems showed no significant difference.

CONCLUSIONS

Salivary gland FNA has high diagnostic accuracy and assists clinical management independently of the reporting system used, however, in some cases, the use of Milan system could be beneficial, since it allows an enhanced category stratification.

A critical appraisal of the Milan system for reporting salivary gland cytology (MSRSGC) with histological correlation over a 3-year period: Indian scenario

BACKGROUND

Fine needle aspiration cytology (FNAC) is the first line investigation for pre-operative diagnosis of salivary gland lesions, but due to its inherent limitations remains a challenge for the cytopathologists. The recently proposed international risk stratification scheme, the Milan System for Reporting Salivary Gland Cytology (MSRSGC) aims to promote and standardise the communication between cytopathologist and clinician thereby improving patient care.

METHODS

A retrospective study of all salivary gland cytology cases was performed over a 3-year period, reviewed by pathologists and categorised into 1 of the 6 diagnostic categories according to MSRSGC, namely, non-diagnostic, non-neoplastic, atypia of undetermined significance (AUS), benign neoplasm, and salivary gland neoplasm of undetermined significance (SUMP), suspicious for malignancy (SFM), and malignant neoplasm. Cyto- histological correlation was done wherever possible. Risk of malignancy (ROM) was calculated for each diagnostic category.

RESULTS

Out of a total of 150 salivary FNAC cases, histopathology was available for 64 cases. The sensitivity of FNAC was 81.8%, specificity was 100% while the diagnostic accuracy was 96.9%. The positive and negative predictive values were 100% and 96.4% respectively. The ROM for non-diagnostic, non-neoplastic, AUS, benign neoplasm, SUMP, SFM, and malignant categories were 0%, 10%, 50%, 2.5%, 50%, 100%, and 100% respectively.

CONCLUSION

MSRSGC fulfils the critical need for a uniform, internationally acceptable reporting system with ROM specified for each category. However, large scale multi centre studies need to be conducted before its reliability and validity is proven.

Updates in Salivary Gland Fine Needle Aspiration Biopsy: The Use of the Milan System and Ancillary Testing

Salivary gland fine needle aspiration biopsies remain common specimens seen by most cytology services. The diagnostic diversity and overlap between many of the lesions seen with these biopsies impart many challenges for the cytopathologist, rendering most specific diagnoses impossible with cytology alone. Here, the use of the Milan System for the classification of salivary gland fine needle aspiration biopsy FNAB is discussed, together with the potential use of ancillary testing in arriving at definitive diagnoses.

Moving Toward a Systematic Approach for Reporting Salivary Gland Cytopathology: An Institutional Experience and Literature Review

Context.—

Despite the clinical utility of fine-needle aspiration for the diagnosis of salivary pathologies, salivary lesions remain one of the most challenging areas in cytopathology. This is partially because there is no consensus on how to report salivary gland cytopathology, which has resulted in inconsistent terminology among institutions and individual cytopathologists and in confusion in communication among cytopathologists and ordering providers.

Objective.—

To summarize our experience with an institutional salivary gland cytopathology reporting system, as an initiative to promote collaborative work toward a consensus on a reporting system.

Design.—

We developed an empirical 6-tier classification reporting system. Slides of 107 salivary gland fine-needle aspirations with subsequent histology slides were reviewed and reclassified using the 6-tier system. The performance of the cytology reporting system was evaluated with the histology diagnoses serving as the gold standard.

Results.—

Fine-needle aspiration diagnoses made based on the institutional 6-tier classification system were generally consistent with histology diagnoses for the disease spectrum reported in this study. The sensitivity, specificity, positive predictive value, and negative predictive value for diagnosing malignancies with the system were 86% (12 of 14), 93% (40 of 43), 80% (12 of 15), and 95% (40 of 42), respectively. The risk of malignancy increased from 0% (0 of 13) for negative for neoplasm to 7% (2 of 29) for benign neoplasm, 67% (2 of 3) for suspicious for malignancy, and 83% (10 of 12) for positive for malignancy.

Conclusions.—

The institutional 6-tier system provides a succinct, risk-of-malignancy–based system to report salivary gland cytology. Our experience with this system helps to pave the way for the adoption of the Milan System for Reporting Salivary Gland Cytopathology.

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC): An ASC-IAC-Sponsored System for Reporting Salivary Gland Fine-Needle Aspiration

The diagnostic role of salivary gland fine-needle aspiration (SG-FNA) is well established in the preoperative evaluation of patients with salivary gland lesions. At present, most salivary SG-FNA specimens are diagnosed based on conventional diagnostic criteria. However, there exists a lack of uniform reporting for these specimens to guide the clinical management of patients. This void motivated a group of experienced cytopathologists to spearhead the development of a uniform reporting system. This international panel, under the sponsorship of the American Society of Cytopathology (ASC) and the International Academy of Cytology (IAC), gathered in September 2015 at the European Congress of Cytology, held in Milan, Italy, to propose the “Milan System for Reporting Salivary Gland Cytopathology” (MSRSGC). This effort sparked the interest of many and brought forth an agreement to develop an evidence-based tiered classification consisting of 6 diagnostic categories. It is hoped that this standard reporting system will enhance the overall effectiveness of SG-FNA reporting across institutions, with the ultimate result being better communication and improved patient care.

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC): an ASC-IAC-sponsored system for reporting salivary gland fine-needle aspiration

The diagnostic role of salivary gland fine-needle aspiration (SG-FNA) is well established in the preoperative evaluation of patients with salivary gland lesions. At present, most salivary SG-FNA specimens are diagnosed based on conventional diagnostic criteria. Nevertheless, there exists a lack of uniform reporting for these specimens to guide the clinical management of patients. This void motivated a group of experienced cytopathologists to spearhead the development of a uniform reporting system. This international panel, under the sponsorship of the American Society of Cytopathology (ASC) and the International Academy of Cytology (IAC), gathered in September 2015 at the European Congress of Cytology, held in Milan, Italy, to propose "The Milan System for Reporting Salivary Gland Cytopathology. This effort sparked the interest of many and brought forth an agreement to develop an evidence-based tiered classification consisting of 6 diagnostic categories. We hope that this standard reporting system will enhance the overall effectiveness of SG-FNA reporting across institutions, with the ultimate result being better communication and improved patient care.

Post-fine-needle aspiration biopsy communication and the integrated and standardized cytopathology report

Communication between cytopathologists and patients and their care team is a critical component of accurate and timely patient management. The most important single means of communication for the cytopathologist is through the cytopathology report. Implementation of standardized terminology schemes and structured, templated reporting facilitates the ability of the cytopathologist to provide a comprehensive and integrated report. Cytopathology has been among the pathology subspecialties that have led the way in developing standardized reporting, beginning with the 1954 Papanicolaou classification scheme for cervical-vaginal cytology and continuing through the Bethesda systems for gynecological cytology and several nongynecological cytology systems. The effective reporting of cytopathology necessarily becomes more complex as it addresses increasingly sophisticated management options, requiring the integration of information from a broader range of sources. In addition to the complexity of information inputs, a wider spectrum of consumers of these reports is emerging, from patients themselves to primary care providers to subspecialized disease management experts. Both these factors require that the reporting cytopathologist provide the integration and interpretation necessary to translate diverse forms of information into meaningful and actionable reports that will inform the care team while enabling the patient to meaningfully participate in his or her own care. To achieve such broad and focused communications will require first the development of standardized and integrated reports and ultimately the involvement of cytopathologists in the development of the clinical informatics needed to treat all these items of information as structured data elements with flexible reporting operators to address the full range of patient and patient care needs. Cancer Cytopathol 2017;125(6 suppl):486-93. © 2017 American Cancer Society.