Updates in head and neck cytopathology: Insights from European Congress of Pathology Short Course

Cytological specimens play a pivotal role in head and neck nodule/mass work up and diagnoses. The specimens´ importance has grown with the onset of personalized medicine and the routine use of molecular markers in the diagnostic work up. The Updates in Head and Neck Cytopathology Short Course ran during the 35th European Congress of Pathology held in Dublin, Ireland, in 2023 and brought together experts in cytopathology, pathology, and related fields to share their expertise and experience in the field of head and neck cytopathology and its future directions. Topics such as a one-stop clinic, the Milan System for Reporting Salivary Gland Cytopathology, next generation sequencing, and human papilloma virus detection in the head and neck area were covered during the short course. These topics are briefly summarized in the present review.

The Milan System for Reporting Salivary Gland Cytopathology: the experience of a tertiary cancer center with emphasis on non-mucinous cysts and improving diagnostic results

INTRODUCTION

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was introduced in 2018 to standardize cytology reporting and guide patient treatment. We aimed to evaluate the utility of this system applied to patients at our cancer center.

MATERIALS AND METHODS

We retrospectively reviewed cases of salivary gland fine-needle aspirations (FNAs) performed in our institution (2019-2022). All were performed by radiologists and immediately assessed for specimen adequacy. The cytologic findings were classified into the MSRSGC except for non-mucinous cystic contents (NMCC) where the lesion was radiologically consistent with a cyst and totally collapsed after FNA. Such lesions were categorized as non-neoplastic (NN) instead of non-diagnostic (ND). The cytologic findings were compared to corresponding histologic findings (212 available cases), and the risk of malignancy was calculated.

RESULTS

Five hundred five FNAs were categorized as: 25 (4.95%) ND; 86 (17.03%) NN, of which 39 were NMCC; 9 (1.78%) atypia of undetermined significance; 138 (27.33%) benign neoplasms; 57 (11.29%) salivary gland neoplasm of undetermined malignant potential; 16 (3.17%) suspicious for malignancy; and 174 (34.46%) malignant. The risk of malignancy rates for the following categories were: ND, 40%; NN, 25%; atypia of undetermined significance, 0%; benign neoplasms, 1%; salivary gland neoplasm of undetermined malignant potential, 54.54%; suspicious for malignancy, 90.9%; and malignant, 100%. Thirty-one NMCC with available follow-up resolved/remained stable.

CONCLUSIONS

Our results validate the reproducibility of the MSRSGC applied in our cancer center. Based on the benign course of cysts with NMCC, we propose that such cases be categorized as NN, provided the cyst is totally resolved after FNA.

Comparison Study of FNAC Using the Milan System Cytopathology versus Definitive Histology for the Diagnosis of Salivary Gland Tumors

INTRODUCTION

Salivary gland tumors (SGT) represent 6 to 8 percent of head and neck tumors. The cytologic diagnosis of SGT is performed by fine-needle aspiration cytology (FNAC) with variable sensitivity and specificity. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) categorizes the cytological results and provides the risk of malignancy (ROM). The aim of our study was to evaluate the cytological findings with the definitive pathological findings to assess the sensitivity, specificity, and diagnostic accuracy of FNAC in SGT according to MSRSGC classification.

METHOD

An observational, retrospective, single-center study was carried out at a tertiary referral hospital over a period of 10 years. Patients that underwent FNAC for major SGT and that have undergone surgery to remove the tumor were included. A histopathological follow-up was performed on the surgically excised lesions. Results from the FNAC were categorized into one of the six MSRSGC categories. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of FNAC for determining benign and malignant cases were calculated.

RESULTS

A total of 417 cases were analyzed. The cytological prediction of ROM was 10% in nondiagnostic, 12.12% in non-neoplastic, 3.58% in neoplasm benign group, 60% in AUS and SUMP groups, and 100% in suspicious and malignant group. The statistical analysis of sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for determining benign cases was 99%, 55%, 94%, 93%, and 94%, respectively, and for determining malignant neoplasm was 54%, 99%, 93%, 94%, and 94%, respectively.

CONCLUSION

In our hands, MSRSGC is highly sensitive for benign tumors and highly specific for malignant tumors. The low sensitivity to differentiate malignant from benign cases makes it necessary to apply an adequate anamnesis, physical examination, and imaging tests to consider surgical treatment in most cases.

Nondiagnostic salivary gland FNAs are associated with decreased risk of malignancy compared with "all-comer" patients: Analysis of the Milan System for Reporting Salivary Gland Cytopathology with a focus on Milan I: Nondiagnostic

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) reports a 25% rate of malignancy (ROM) for the Milan I: Nondiagnostic (ND) category. We clarify the ROM of ND salivary gland fine-needle aspirations (SGFNAs) based on our institutional experience and review of the literature.

METHODS

Overall risk of malignancy (OROM) and that for those with surgical/flow cytometric follow-up (FROM) for each category and "all-comers" were calculated for Emory SGFNAs from January 2010 through March 2021. From a literature review of 50 articles using MSRSGC, distribution of diagnoses, rates of follow-up, FROM, and OROM by category were calculated. FROMs and OROMs between ND FNAs and all-comers were compared. Milan I rate was compared with the ratio of Milan I OROM to all-comer OROM.

RESULTS

Of 819 SGFNAs at Emory, 12.8% (n = 105/819) were ND. Thirty-two had known follow-up, with 12 (37.5%) being malignant. Nonmucinous cyst contents accounted for 26.7% of ND SGFNAs (n = 28/105); all 7 with surgical follow-up were benign. Of 50 MSRSGC studies, 18.2% (n = 2384/13,129) of SGFNAs were classified as ND, 26.6% (n = 635/2384) with known follow-up. Total FROM and OROM for ND FNAs (15.7% and 4.1%, respectively) were significantly lower than those for all-comers (24.9% and 11.4%, respectively) (p < .001). There was no relationship between rate of ND SGFNA and ND ROM.

CONCLUSIONS

The ND category is associated with a lower ROM than that of all-comer SGFNA patients. The "true" ROM for ND SGFNAs is likely best estimated by the 4.1% OROM. SGFNAs showing nonmucinous cyst contents have a particularly low ROM. Rate of ND SGFNAs does not influence ND ROM.

The Milan System classification of Warthin tumor: A large institutional study of 124 cases highlighting cytologic features that limit definitive interpretation

BACKGROUND

Fine-needle aspiration (FNA) is highly accurate for the diagnosis of Warthin tumor (WT). However, there is a minor subset of WT cases that are more challenging to interpret. The goal of this study is to identify factors that limit definitive diagnosis of WT on FNA.

METHODS

All WT surgical specimens diagnosed during a 6.5-year study period were retrospectively identified and the preceding cytologic specimen diagnostic categories were analyzed. Of particular interest were WT cases with indeterminate or malignant interpretations. Cases that noted squamous or mucinous change in either the surgical or cytologic reports were also reviewed.

RESULTS

A total of 157 WT surgical specimens were identified, with 124 (79.0%) having prior FNAs. The distribution of cytologic diagnostic categories was 12 (9.7%) nondiagnostic, 10 (8.1%) nonneoplastic, 13 (10.5%) atypia of undetermined significance (AUS), 82 (66.1%) neoplasm: benign, 4 (3.2%) salivary gland neoplasm of uncertain malignant potential (SUMP), 2 (1.6%) suspicious for malignancy, and 1 (0.8%) malignant. Of the 20 cases in indeterminate/malignant categories, a majority noted either squamoid (9 of 20) or mucinous (2 of 20) changes. The remainder noted scant cellularity as a limiting factor to interpretation. Additionally, 27 cases mentioned squamous or mucinous change in the surgical or cytology report, with a wide spectrum of cytologic categorization including 2 (7.4%) nondiagnostic, 2 (7.4%) nonneoplastic, 7 (25.9%) AUS, 8 (29.6%) neoplasm: benign, 4 (14.8%) SUMP, 2 (7.4%) suspicious for malignancy, and 1 (3.7%) malignant.

CONCLUSIONS

This study identified 2 key causes for indeterminate or misclassification of WT on FNA: specimen hypocellularity and metaplastic changes. Recognition of the potential for squamous and mucinous metaplastic changes combined with observance of some helpful diagnostic clues such as the presence of crystalloids may aid in preventing diagnostic pitfalls.

Evaluation of Accuracy of Salivary Gland Fine Needle Aspirates using the Milan System for Reporting Salivary Gland Cytopathology

CONTEXT

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a standardized six tier-reporting format aimed at ensuring better communication and improved patient management.

AIMS

The main objectives of our study were to classify salivary gland fine needle aspirates into 6 categories of the MSRSGC and assess Risk of malignancy (ROM), specificity, sensitivity, Positive Predictive Value and Negative Predictive Value.

SETTINGS AND DESIGN

It was a retrospective study done over a period of three years from January 2017 to December 2020.

MATERIALS AND METHODS

All salivary gland FNAs performed in the above period were retrieved and classified into six categories based on the Milan system. Histopathological diagnosis was also retrieved wherever available.

STATISTICAL ANALYSIS

Using histopathological diagnosis as gold standard, ROM was calculated. Specificity, sensitivity, PPV, NPV and diagnostic accuracy were also assessed.

RESULTS

Out of the 202 salivary gland FNAs, histopathological diagnosis was available in 102 cases. ROM for Non Diagnostic, Non Neoplastic, Atypia of Undetermined Significance (AUS), Benign, Salivary Gland Neoplasm of Uncertain Malignant Potential (SUMP), Suspicious for Malignancy (SM) and Malignant categories was 30%, 8.3%, 25%, 3.9%, 33.3%, 71.4% and 93.3% respectively. Highest specificity and diagnostic accuracy were achieved when only malignant and SM were considered as positive results. Maximum sensitivity was observed when AUS, SUMP, SM and malignant were included in positive test results.

CONCLUSION

The MSRSGC is an excellent system for accurately classifying salivary gland FNAs with better reproducibility of reports and enhanced communication between pathologist and surgeon.

The Milan System for Reporting Salivary Gland Cytopathology: Assessment of Cytohistological Concordance and Risk of Malignancy

INTRODUCTION

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was proposed by the American Society of Cytopathology and the International Academy of Cytology to bring uniformity in the reporting system and the treatment protocol. A wide range of risk of malignancy for each category has been reported by various authors by applying the system.

AIM

We intend to study the cytohistological concordance and the ROM for each of the diagnostic categories of the Milan system.

MATERIALS AND METHODS

The study included 292 cases of fine-needle aspiration cytology (FNAC) of salivary gland lesions over a period of 3 years. The diagnosis of these cases was reclassified into the 6 categories of the Milan system. The cytohistological concordance and ROM for each category of the Milan system were calculated based on the clinical and histopathological follow-up.

RESULTS

The patients' age ranged from 3 to 81 years with the mean of 42.65 ± 16.3 years. The cases included 189 (64.7%) parotid, 82 (28.1%) submandibular, and 21 (7.2%) cases of minor salivary gland swellings. Follow-up histopathological diagnosis for 102 cases was available. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated to be 64.28, 97.01, 90, 86.67, and 87.37%, respectively. After reclassification, the number of cases in each category was as follows: category I: 31 (10.62%), category II: 80 (27.4%), category III: 2 (0.68%), category IVA: 143 (48.97%), category IVB: 1 (0.34%), category V: 13 (4.45%), and category VI: 22 (7.53%). The calculated ROM was as follows: category I: 42.86%, category II: 26.67%, category III: 100% category IVA: 10.17%, category IVB: 0%, category V: 71.42%, category VI: 100%.

CONCLUSION

FNAC is an excellent procedure to differentiate benign from malignant tumors, and MSRSGC is a useful system for risk assessment and deciding the further treatment protocol. Our findings also suggest that in addition to the surgical follow-up, inclusion of the clinical and radiological follow-up may be a better strategy for calculation of ROM, especially for categories I and II.

Retrospective application of the Milan System for reporting salivary gland cytopathology: A Cancer Center experience

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was recently proposed. Herein, we retrospectively applied this nomenclature system to salivary gland lesions sampled by ultrasound-guided fine-needle aspiration (FNA).

METHODS

All cases of salivary gland FNA with available surgical follow-up, in the period from 2014 to 2017 at our institution were reviewed and reclassified according to one of the six categories of the MSRSGC, blind to the surgical outcome. Overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated, as well as risks of neoplasm (RON) and risk of malignancy (ROM) for each of the proposed categories.

RESULTS

There were 104 salivary gland lesions, with a female predominance (57.7%), most cases from the parotid gland (89.4%). Mean age was 53.2 years. Distribution of the specimens according to the Milan System was as follows: 19.2% nondiagnostic (ND), 8.7% non-neoplastic (NN), 9.6% atypia of undetermined significance (AUS), 40.4% benign neoplasm (BN), 14.4% salivary gland neoplasm of uncertain malignant potential (SUMP), 1.9% suspicious for malignancy (SFM), and 5.8% malignant. Sensitivity, specificity, PPV, and NPV using MSRSGC were calculated as 75%, 98.4%, 88.9%, and 95.3%, respectively. RON/ROM for each category were 60%/15% for ND, 44.4%/0% for NN, 90%/40% for AUS, 100%/9.5% for BN, 100%/13.3% for SUMP, 50%/50% for SFM and 100%/100% for malignant.

CONCLUSION

The use of the Milan System proved to be a useful method to predict the risk of neoplasm and malignancy in the sample studied, with high sensitivity and specificity.

[Salivary gland cytopathology: Milan system 2018]

The salivary glands cytology is one of the most challenging area in cytopathology because of the wide diversity of benign and malignant tumors also because of their heterogeneity. However, fine needle aspiration cytology, with magnetic resonance imaging, represents a first-line examination to guide a possible surgical procedure and its extent. An accurate diagnosis of a specific tumor is sometimes difficult to assess in cytology. Also, as for gynecological, thyroid or urinary cytologies, a panel of experts met to develop a cytological classification of salivary gland lesions associated with a risk of malignancy and management proposals. The Milan System for Reporting Salivary Gland Cytopathology was published in 2018. The French Society of Clinical Cytology (SFCC) offers here an official summarized French version oh this terminology and recommends its use.

Application of the Milan System for Reporting Salivary Gland Cytopathology: A retrospective study in a tertiary institute

BACKGROUND

Fine needle aspiration (FNA) cytology has been widely used in the preoperative evaluation of salivary gland lesions. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a tiered risk-stratification scheme designed to standardize reporting and facilitate decision making. We aimed to clarify the validity and diagnostic utility of the MSRSGC-based classification of salivary gland lesions.

METHODS

A total of 1020 salivary gland FNA specimens were retrieved between 2008 and 2017, with histologic follow-up data available for 349 specimens. Within the present retrospective study, each specimen with follow-up data was reclassified according to the MSRSGC diagnostic categories: nondiagnostic, nonneoplastic, atypia of undetermined significance (AUS), benign neoplasm, salivary gland neoplasm of uncertain malignant potential (SUMP), suspicious for malignancy (SM), and malignant. The risk of malignancy (ROM) was calculated based on the histologic follow-up data.

RESULTS

The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the MSRSGC-based classification of the malignant potential of salivary gland lesions were 80.1%, 70.4%, 99.2%, 90.5%, and 96.7%, respectively. The ROM calculated for specimens assigned to the nondiagnostic, nonneoplastic, AUS, benign neoplasm, SUMP, SM, and malignant categories were 8.6%, 15.4%, 36.8%, 2.6%, 32.3%, 71.4%, and 100%, respectively.

CONCLUSION

The present results confirm the validity and diagnostic utility of MSRSGC, supporting its use in clinical practice to help devise adequate management strategies for salivary gland lesions.

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.

Risk-based Stratification of Salivary Gland Lesions on Cytology: An Institutional Experience

BACKGROUND & OBJECTIVE

Fine needle aspiration cytology (FNAC) of salivary gland lesions is an accepted and useful diagnostic tool to differentiate between benign and malignant lesions. Majority of the neoplasms are benign, and specific diagnosis on cytology can be made in most of the cases. However, the utility is limited by the overlapping and heterogeneous morphological features of benign and malignant neoplasms. The current study aimed at investigating the cytomorphological features of salivary gland lesions with histopathological correlation and performing risk based stratification of these lesions using the recommended Milan system for reporting of salivary gland cytopathology (MSRSGC).

METHODS

The current study was conducted on 192 retrospective and prospective cases of salivary gland lesions over a period of three years from October 2014 to September 2017. Cytohistopathological correlation was observed in 62 cases. Subsequently,cytomorphological features were further revaluated, classified according to MSRSGC into six groups, and correlated with clinico-histopathological features.

RESULTS

Diagnostic sensitivity and specificity of FNAC for salivary gland lesions was 63.16% and 97.62%, respectively. The positive predictive value was 92.31% and negative predictive value was 85.42%. The diagnostic accuracy to differentiate between benign and malignant lesions was 86.88%.The number of cases in each diagnostic category and the risk of malignancy (ROM) were as follows: nondiagnostic - three cases (ROM - 33.33%), nonneoplastic - 14 cases (ROM - 7.14%), atypical - one case (ROM - 100%), benign - 28 cases (ROM - 7.14%), NUMP - one case (ROM - 100%), suspicious - one case (ROM -100%), and malignant - 13cases (ROM - 92.30%).

CONCLUSION

Risk based stratification scheme as recommended by MSRSGC can provide a standard method to analyse the results and help to plan the management of salivary gland lesions.

Impact on clinical follow-up of the Milan System for salivary gland cytology: A comparison with a traditional diagnostic classification

INTRODUCTION

No universally accepted classification exists for salivary gland FNA. The proposed Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) offers a uniform classification with management recommendations. We compared FNA diagnoses from a prior study with specific diagnoses with corresponding MSRSGC diagnoses.

METHODS

One-hundred and sixty-four cases from a prior cytological study with histological follow-up were re-reviewed by one of the authors and assigned to one of the MSRSGC categories. The original and MSRSCG diagnoses were compared, as were follow-up recommendations.

RESULTS

The MSRSGC system classified 29 specimens as non-diagnostic (seven histologically shown to be benign salivary gland, two non-mucinous cysts, 14 sialadenitis, one pleomorphic adenoma, one haemangioma, one lymphoma, one adenoid cystic carcinoma, one squamous carcinoma and one benign lymphoid proliferation). The original study diagnosed these lesions as: seven benign cysts, 15 benign salivary gland tissue, one benign neoplasm and two insufficient for diagnosis. In seven cases, MSRSGC disagreed with original diagnoses and surgical resection showed lesions where optimal follow-up was more consistent with original cytological diagnosis. In 10 cases with disagreement, the MSRSGC was associated with a more appropriate follow-up based on the surgical diagnosis. Malignancy risks for the Milan categories were: non-diagnostic (12%), non-neoplastic (5%), atypia of undetermined significance (19%), neoplasm, benign (5%), neoplasm (40%), suspicious for malignancy (60%) and malignant (93%).

CONCLUSION

MSRSGC was comparable with the original reported diagnoses in the majority of cases. Both systems had high accuracy for distinguishing benign from malignant lesions and both were associated with appropriate follow-up in most cases.