Application of the Milan System for Reporting Salivary Gland Cytopathology: A Retrospective 12-Year Bi-institutional Study

Rapid on-site evaluation improves diagnostic performance of fine-needle aspiration cytology for salivary lesions: Comparison of data from two cancer centers in southern China

OBJECTIVES

To evaluate the diagnostic performance of Milan system for reporting salivary gland cytopathology (MSRSGC) in two southern China tertiary cancer centers and investigate the impact of rapid on-site evaluation (ROSE) on FNAC performance.

MATERIALS AND METHODS

Five hundred and forty-nine patients who underwent FNAC for salivary lesions with surgical follow-up from two centers were enrolled in this retrospective cohort study. All slides were recategorized using MSRSGC after consensus on diagnostic criteria for each category. The diagnostic performance of FNAC for salivary lesions was evaluated and compared and the impact of ROSE on FNAC performance was analyzed.

RESULTS

The distribution of cases per category based on the MSRSGC criteria in the whole series was as followed: ND 49 (8.9%), NN 76 (14.4%), BN 262 (47.7%), AUS 20 (3.6%), SUMP 43 (7.8%), SM 21 (3.8%), M 78 (14.2%). The SUMC series had significantly more ND distributions than JXCH did (16.2% vs. 0, p = .000). Risk of malignancy for each category in the total series was as followed: 42.9% for ND, 9.2% for NN, 3.8% for BN, 30.0% for AUS, 23.3% for SUMP, 81.0% for SM, and 94.9% for M. When ND and AUS/SUMP were excluded, the sensitivity, specificity, PPV, NPV, and accuracy were 84.0%, 97.1%, 89.9%, 95.1%, and 94.0%, respectively; sensitivity, specificity, PPV, NPV, and accuracy were comparable between the two centers.

CONCLUSIONS

FNAC using MSRSGC provides a good tool in preoperative evaluation for salivary lesions in southern China. ROSE improves its diagnostic performance by reducing the ratio of the ND category.

Milan system for reporting salivary gland cytology in diagnosis and surgery of parotid gland lesions

INTRODUCTION

A cytology report is always a challenge for both head and neck surgeons and cytopathologists to diagnose and manage parotid gland (PG) diseases, because of the various similar features between the lesions.

OBJECTIVES

The present study was conducted to assess our practice using the Milan System for Reporting Salivary Cytopathology (MSRSGC) and to evaluate the risk of malignancy (ROM) in different categories.

PATIENTS AND METHODS

The patients with parotid gland lesions were diagnosed by clinical examination, ultrasound, and FNAC under ultrasound guidance at our hospital from 1 May 2019 to 30 April 2021. The FNAC results were divided into six categories according to the Milan system. We calculated the ROM for each category of the Milan system based on histopathological follow-up.

RESULTS

This study included 204 patients. There were 115 men (56 %) aged 46-60 years. Pathology results were 33 cases for malignant and 182 cases for benign. The rate of malignancy for each category according to the MSRSGC were 23.1 % (non-neoplastic), 20 % (atypical), 50 % (neoplastic), 1 % (benign), 10.3 % (salivary neoplasm of uncertain neoplastic potential), 84.6 % (suspicious for malignancy), and 100 % (malignant) categories. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNAC with application of Milan system were respectively 90.9 %, 98.2 %, 90.9 %, 98.9 % and 97 %.

CONCLUSION

When the Milan system was applied, FNAC had a high efficacy, suggesting that MSRSGC can improve the communication between the cytopathologist and the surgeon. This system can allow the surgeon to decide the extent of the surgery.

Prioritizing parotid gland surgery: A call for the implementation of the MSRSGC classification

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is developed to aid diagnosis and management of salivary gland tumors. This study evaluates the time-to-treatment initiation (TTI) for parotid gland tumors in the Netherlands and relates these to the MSRSGC classification. Subsequently, the use of the MSRSGC in the Netherlands is evaluated.

METHODS

Data regarding fine-needle aspiration cytology (FNAC) and histopathological resections of the parotid were gathered from the Dutch nationwide pathology data bank (PALGA). The TTI was calculated for each MSRSGC category and type of treating center. FNACs performed from 2018 to 2021 were gathered from PALGA to estimate how frequently the MSRSGC classification was applied.

RESULTS

Median TTI in days were 86 for nondiagnostic (MSRSGC I), 75 for nonneoplastic (MSRSGC II), 65 for atypia of unknown significance (AUS) (MSRSGC III), 89 for benign (MSRSGC IVa), 52 for salivary gland neoplasm of unknown malignant potential (SUMP) (MSRSGC IVb), 31 for suspected malignant (MSRSGC V), and 30 for malignant (MSRSGC VI) categories. Significant variation in the TTI between the types of treating centers was found for the nondiagnostic, nonneoplastic, AUS, SUMP, and suspected malignant categories. In the first 3 years after the introduction of the MSRSGC, the pathologist stated the MSRSGC classification in 6.4% of all reports.

CONCLUSIONS

The median TTI for most categories is long, and there is significant interhospital variation in TTI. Preoperative risk stratification and treatment prioritization in parotid gland surgery in the Netherlands should be improved. The MSRSGC could contribute to this. Until 2021, the MSRSGS classification was implemented on a limited scale in the Netherlands.

Evaluation of Fine Needle Aspiration Cytopathology in Salivary Gland Tumors under Milan System: Challenges, Misdiagnosis Rates, and Clinical Recommendations

(1) Background: Salivary gland tumors are rare in the head and neck. To determine the need and extent of surgical intervention, fine needle aspiration (FNA) is a widely accepted tool to approach salivary gland lesions. However, the FNA cytology varies between entities, while the lack of uniform terminology makes diagnosis more challenging. Since establishing the Milan system for reporting salivary gland cytopathology (MSRSGC) has become an increasingly accepted reporting standard, further examination and detailed recommendations were needed. (2) Methods: Between April 2013 and October 2021, 375 cases with FNA and salivary gland resection were retrospectively collected. All FNA specimens were reclassified according to the criteria of MSRSGC. After surgical excision, the FNA data were compared with the histological diagnosis to estimate the risk of malignancy (ROM), the risk of neoplasm (RON), and the diagnostic accuracy for each diagnostic category. (3) Results: Our cohort's distribution of ROM and RON was similar to the MSRSGC's recommendation. Carcinoma ex pleomorphic adenoma (CXPA) has the highest rate (66.7%) of misdiagnosed as a nonneoplastic lesion or benign salivary gland tumor. Pleomorphic adenoma (PA) and Warthin's tumor were the most common benign salivary gland tumors, while the cytology diagnosis of Warthin's tumor seems more challenging than PAs. (4) Conclusions: Despite the convenience and effectiveness of MSRSGC, we suggest close follow-up, re-biopsy, or surgical removal for salivary lesions even in Milan IVA-Benign for possibly missing FNA of malignancy, mixed lesions, or prevention of malignant transformation.

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.

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.

Validation of the Milan system for reporting salivary gland cytopathology: a single institution's 10-year experience

INTRODUCTION

Fine needle aspiration cytology is often used for the initial diagnosis and management of patients with salivary gland tumors. Because of its global usage, a consensus classification schema was devised in 2018 to initiate universal reporting of salivary gland cytology specimens, termed the Milan system for reporting salivary gland cytopathology (MSRSGC) and composed of distinct diagnostic categories. Few retrospective studies have been undertaken to review the MSRSGC within institutions.

MATERIALS AND METHODS

We analyzed salivary gland fine needle aspirations during a 10-year span from 2011 to 2021, categorized each cytology case to fit the MSRSGC, and subsequently reviewed the corresponding surgical resections, if indicated, to determine the rate of malignancy (ROM) and rate of neoplasia.

RESULTS

Our ROM was higher (>10%) for the following MSRSGC categories: non-neoplastic, atypia of undetermined significance, and suspicious for malignancy. Also, our data correlated well with the following MSRSGC categories: nondiagnostic, neoplasm-benign, salivary gland neoplasm of uncertain malignant, and malignant.

CONCLUSIONS

Although the data were indicative of the ROM for surgically resected salivary gland lesions, the ROM for non-neoplastic lesions could truly be lower given that most lesions in this category will not undergo surgical resection. Additionally, determination of the rate of neoplasia could a tool that could be used to further guide our clinical colleagues.

Application of the Milan system for reporting salivary gland cytopathology using cell blocks

The Milan system for reporting salivary gland cytopathology (MSRSGC) is a novel standardized classification tool for salivary gland cytology specimens based on the use of direct smears. Formalin-fixed paraffin-embedded (FFPE) cell blocks facilitate the use of ancillary studies, leading to improved diagnostic accuracy. However, the application of the MSRSGC with only cell blocks has not been well established. Consecutive cohort of all parotid gland cytology specimens between 01/01/2018 and 30/06/2021 was performed. All cytology specimens were processed into cell blocks only. Cytologic diagnoses were classified prospectively according to the MSRSGC categories. The risk of malignancy (ROM) for each diagnostic category and the diagnostic performance were calculated. A total of 230 FNA samples from 221 patients were identified, including 47% and 78.4% with surgical or clinical follow-up, respectively. The ROMs based on surgical follow-up for the non-diagnostic, non-neoplastic, AUS, neoplasm: benign, SUMP, SFM and malignant categories were 21.4%,0%,50%,0%,30%,100% and 100%, respectively. The ROMs based on the clinical follow-up for these categories were 7.3%,0%,37.3%,0%,27.3%,100% and 100%, respectively. Following surgical excision, all Milan IVa category samples were confirmed as benign, and all Milan V and VI category samples were confirmed as malignant. This study validates the application of the MSRSGC with the sole use of FFPE cell blocks. The diagnostic accuracy of MSRSGC is high and compares favorably to other institutions using traditional cytology assessment methods. Furthermore, FNA results using this technique enabled to provide optimal patient management based on the ROM of the different Milan system categories.

Patient safety and quality improvements in parotid surgery

Parotidectomy is the mainstay treatment for tumors of the parotid gland. In an effort to improve clinical outcomes, several modern surgical techniques and perioperative interventions have been evaluated and refined. This review discusses current and actively debated perioperative interventions aimed at improving patient safety and the quality of parotidectomy. Relevant high-impact literature pertaining to preoperative diagnostic modalities, intraoperative surgical techniques, and postoperative care will be described.

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.

Multi-institutional validation of a modified scheme for subcategorizing salivary gland neoplasm of uncertain malignant potential (SUMP)

BACKGROUND

The salivary gland neoplasm of uncertain malignant potential (SUMP) category in the Milan System is diagnostically challenging. This study aims to validate a modified scheme for subcategorizing SUMP in a large multi-institutional cohort.

METHODS

Retrospective review of salivary gland fine-needle aspirations (FNAs) from 10 institutions were classified based on the Milan System. Cases diagnosed as SUMP with available cytology slides and surgical follow-up were retrieved for review and subcategorized based on a modified scheme as follows: basaloid SUMP (B1: absent/scant nonfibrillary matrix; B2: presence of nonfibrillary/mixed-type matrix), oncocytic/oncocytoid SUMP (O1: with mucinous background; O2: without mucinous background), and SUMP not otherwise specified (NOS).

RESULTS

A total of 742 (7.5%) cases from 9938 consecutive salivary gland FNAs were classified as SUMP. Among them, 525 (70.8%) had surgical follow-up and 329 (62.7%) were available for review. The overall risk of malignancy (ROM) of SUMP was 40.4%. There were 156 cases (47.4%) subcategorized as basaloid SUMP with a ROM of 36.5%, 101 (30.7%) as oncocytic/oncocytoid SUMP with a ROM of 52.5%, and 72 (21.9%) as SUMP NOS with a ROM of 31.9%. The ROM of oncocytic/oncocytoid SUMP was significantly higher than basaloid SUMP (P = .0142) and SUMP NOS (P = .0084). No significant differences in ROM were noted between B1 and B2 (36.7% vs 36.4%, P = 1.0000) and O1 and O2 (65.2% vs 48.7%, P = .2349).

CONCLUSIONS

The ROM of oncocytic/oncocytoid SUMP was 52.5% and significantly higher than that of basaloid SUMP (36.5%, P = .0142) and SUMP NOS (31.9%, P = .0084), whereas no significant differences in ROM were noted for cases with different types of extracellular matrix or background material.

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.

Reclassification of salivary gland aspirates based on “The Milan system for reporting salivary gland cytology”: A five-year retrospective study

Introduction:

The Milan System for reporting salivary gland cytopathology helps standardize reporting systems across institutions, improve communication between clinicians and pathologists and guide the clinical management of patients.

Aims:

This study was undertaken to evaluate the utility of the Milan system classification in cytology reporting.

Settings and Design:

The present study is a retrospective study conducted over a period of five years in tertiary care centre.

Methods and Materials:

All the cases of salivary gland aspirates were reviewed and reclassified into six diagnostic categories according to the Milan system of reporting salivary gland cytology (MSRSGC). Cytological diagnosis was correlated with the histopathological diagnosis wherever available.

Results:

A total of 258 cases were classified using the Milan system as non-diagnostic (20.9%), non-neoplastic (26.3%), atypia of undetermined significance (4.7%), neoplasm benign (37.5%), neoplasm of uncertain malignant potential (3.5%), suspicious for malignancy (0.4%), and malignancy (6.6%). Cytohistological discordance was noted among 8/76 cases (10.5%). The sensitivity and specificity of FNAC were 75% and 98.5%, respectively. The risk of malignancy was 14.2% for Category I, 9% for II, 50% for III, zero for IVA and IVB, and 83.3% for category VI.

Conclusions:

The new classification system helps pathologists to standardize reporting leading to better clinical and surgical management.

Utility of the Milan System for Reporting Salivary Gland Cytology, with focus on the incidence and histologic correlates of atypia of undetermined significance (AUS) and salivary gland neoplasm of uncertain malignant potential (SUMP): A 3-year institutional experience

BACKGROUND

Fine-needle aspiration (FNA) is the preferred diagnostic test for salivary gland lesions. The purpose of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is to standardize salivary gland cytology reporting and guide treatment decisions. The objective of the current study was to evaluate the utility and performance of the MSRSGC, with a focus on the cytomorphology of lesions diagnosed as atypia of undetermined significance (AUS) and salivary gland neoplasm of uncertain malignant potential (SUMP).

METHODS

In total, 123 salivary gland FNAs were included in the study. FNA diagnoses for all cases were reviewed and recategorized, as applicable, according to the MSRSGC. Cytohistologic correlation was performed in 51 cases that had available surgical follow-up, and the risk of malignancy (ROM) was calculated.

RESULTS

Most FNA samples were from the parotid gland. The mean patient age was 61.4 years, and the male-to-female ratio was 1.3:1. The ROM was 0% (categories I and II; nondiagnostic and benign nonneoplastic, respectively), 50% (category III; AUS), 0% (category IVA; benign neoplasm), 40% (category IVB; SUMP), 100% (category V; suspicious for malignancy), and 100% (category VI; malignant). Sensitivity, specificity, positive predictive value, and negative predictive value were 100% each. In addition, the primary factors for an AUS diagnosis were identified as low cellularity and/or the presence of lymphocytes. The presence of oncocytes followed by cellular atypia in an otherwise classic pleomorphic adenoma were principal factors for a SUMP diagnosis.

CONCLUSIONS

The authors report an ROM comparable to that reported in the literature, with a sensitivity and specificity of 100%, supporting adaptation of the MSRSGC into the system for reporting salivary gland cytology. In addition, the findings emphasize the need to refine criteria for AUS and SUMP, thereby improving the predictive capability and subsequent management of salivary gland lesions.

Validation of the Milan System for Reporting Salivary Gland Cytopathology and the diagnostic accuracy of FNA cytology for submandibular gland lesions

BACKGROUND

The Milan System for Salivary Gland Cytopathology (MSRSGC) is a categorical system for salivary gland fine-needle aspiration cytopathology (FNAC) developed to aid clinicians in the management of salivary gland lesions. This classification is widely studied and validated, especially in cohorts that consist of mostly parotid gland lesions. However, only sparse literature describes the use of this classification for submandibular gland lesions in particular.

METHODS

All patients in the Netherlands that underwent a submandibular gland resection between January 1, 2006, and January 1, 2017, with a FNAC before resection were identified with the use of the Dutch Pathology Registry database (PALGA). All FNAC results were retrospectively classified according to the MSRSGC. The risk of malignancy was calculated for all the MSRSGC categories. The sensitivity and specificity of the MSRSGC classification were calculated for submandibular gland FNAC.

RESULTS

A total of 837 patients who underwent 975 FNAC aspirates from the submandibular glands were included in the analysis. Risks of malignancy for each of the MSRSGC categories were 14.4% in nondiagnostic, 4.4% in nonneoplastic, 37.0% in atypia of unknown significance, 3.9% in benign neoplasms, 40.7% in salivary gland neoplasms of unknown malignant potential, 76.2% in suspected malignant, and 91.3% in malignant cytology results. The sensitivity for diagnosing malignant submandibular gland tumors was 71.6% and specificity was 98.4%.

CONCLUSIONS

The results of the present study validate the use of this classification for submandibular gland lesions. Risks of malignancy vary according to the anatomical subsites of the salivary gland lesions.

LAY SUMMARY

The risks of malignancy of the various Milan System for Salivary Gland Cytopathology (MSRSGC) categories vary according to the anatomical subsite of the salivary gland lesion. The proposed management techniques of the MSRSGC are valid for use with submandibular gland lesions.

A multi-institutional study of salivary gland cytopathology: Application of the Milan System for Reporting Salivary Gland Cytopathology in Japan

Background

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a risk‐stratification reporting system that was introduced in 2018. The objective of this multi‐institutional study was to evaluate the utility of the MSRSGC in Japan.

Methods

In total, 1608 fine‐needle aspiration samples with matching histologic diagnoses were retrieved from 12 large institutions in Japan. The diagnostic categories of the MSRSGC were assigned prospectively or retrospectively, and the results were compared with the histologic diagnoses.

Results

The cases were classified as follows: nondiagnostic, 18.1%; non‐neoplastic, 4.1%; atypia of undetermined significance, 11.5%; neoplasm‐benign, 43.7%; salivary gland neoplasm of uncertain malignant potential, 9.6%; suspicious for malignancy, 3.6%; and malignant, 9.4%. The risk of neoplasm and the risk of malignancy in each MSRSGC category were as follows: nondiagnostic, 72.9% and 13.4%, respectively; non‐neoplastic, 15.2% and 9.1%, respectively; atypia of undetermined significance, 77.9% and 24.9%, respectively; neoplasm‐benign, 99% and 1.8%, respectively; salivary gland neoplasm of uncertain malignant potential, 94.8% and 37%, respectively; suspicious for malignancy, 100% and 89.7%, respectively; and malignant, 100% and 99.3%, respectively. The accuracy of the MSRSGC for diagnosing neoplasms was 97.8%, and its accuracy for diagnosing malignancy was 97.3%. Institutions that used Romanowsky‐stained preparations had lower nondiagnostic rates and lower risks of neoplasm and malignancy in the non‐neoplastic category.

Conclusions

The MSRSGC is useful for risk stratification and quality control. Widespread use of the MSRSGC would improve the accuracy of salivary gland cytology and lead to better patient care in Japan.

This is the first multi‐institutional study of a large‐scale application of the Milan System for Reporting Salivary Gland Cytopathology in Japan. It demonstrates the usefulness of the Milan system in the diagnosis of salivary gland lesions and for the quality control of salivary gland cytology results.

Utility of the Milan system for reporting salivary gland cytopathology during rapid on-site evaluation (ROSE) of salivary gland aspirates

OBJECTIVE

Rapid on-site evaluation (ROSE) is a fine needle aspiration (FNA) technique for ensuring sampling adequacy and triaging samples. The Milan system for reporting salivary gland cytopathology (MSRSGC) is a standardised reporting system which aims to improve risk stratification. There is scant literature on the diagnostic value and agreement of MSRSGC on ROSE with final cytological diagnosis in salivary gland FNAs. We aimed to assess the concordance of MSRSCG categorisation and diagnosis on ROSE with final cytological and histological diagnosis.

METHODS

This prospective study included consecutive salivary gland FNAs for which ROSE was performed over a six-month period. MSRSGC category and diagnosis on ROSE were compared with the final cytological diagnosis and MSRSGC category, and histopathological diagnosis, where available.

RESULTS

Sixty salivary gland aspirates were included. The adequacy rate with ROSE was 100%. Using the MSRSGC classification during ROSE, 26 (43.2%) samples were categorised as benign neoplasm, 21 (35%) as malignant neoplasm, 9 (15%) as non-neoplastic, and one each (1.7%) belonged to the remaining four categories. MSRSGC categorisation on ROSE concurred with final the cytological diagnosis in 58/60 cases (96.7%). Discrepancies in MSRSGC categories on ROSE included one atypia of undetermined significance with final report as non-neoplastic, and one non-diagnostic as suspicious for malignancy. Good correlation of MSRSGC categories on ROSE with final histopathological diagnosis (88.9% concordance) was also noted.

CONCLUSIONS

MSRSGC on ROSE shows good concordance with final cytology and histopathology diagnosis, indicating that categorisation according to MSRSGC has utility in ensuring that adequate material is obtained and triaged appropriately for the diagnosis of salivary gland aspirates.

Is Milan for kids?: The Milan System for Reporting Salivary Gland Cytology in pediatric patients at an academic children's hospital with cytologic-histologic correlation

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) provides a useful framework for the diagnosis of salivary gland fine-needle aspiration (FNA) biopsies. In this study, the MSRSGC was applied to salivary gland FNAs in pediatric patients to assess its usefulness and look at pitfalls.

METHODS

The laboratory information system was queried over a 15-year period for all salivary gland FNAs in patients 18 years old or younger. Patient demographics, FNA diagnosis categorized according to the MSRSGC, and follow-up surgical pathology diagnoses were examined and correlated.

RESULTS

Thirty-two cases were identified, with an average age of 12 years (range, 0.6-18 years). A majority of the cases (84.4%) were from the parotid region. Twenty of 32 cases (62.5%) had follow-up resection. MSRSGC recategorization diagnoses of the 32 FNA cases were 34% benign neoplasm, 31% nonneoplastic, 16% nondiagnostic, 9% atypia of undetermined significance, 3% salivary neoplasm of uncertain malignant potential, 3% suspicious for malignancy, and 3% malignant. Overall, the sensitivity and specificity were 100% and 80%, respectively. On follow-up resection, 55% were neoplastic: pleomorphic adenomas (n = 6; 55%), pilomatricoma (n = 3; 28%), mucoepidermoid carcinoma (n = 1; 9%), schwannoma (n = 1; 9%), and myofibroma (n = 1; 9%).

CONCLUSIONS

The MSRSGC performed fairly well in the pediatric population with a low overall risk of malignancy (6%) and high sensitivity. Although the majority of pediatric salivary gland FNAs were benign, 55% of resected cases were positive for a neoplasm, with benign neoplasms outnumbering malignancy. Challenging entities included inflammatory conditions, like immunoglobulin G4-related sialadenitis, and skin and soft tissue lesions near the salivary gland.

The Milan System for Reporting Salivary Gland Cytopathology: An outcome of retrospective application to three years' cytology data of a tertiary care hospital

Objectives:

Fine-needle aspiration cytology (FNAC) of the salivary gland lesions has diverse and sometimes overlapping features that pose a diagnostic challenge for the cytopathologists. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has been introduced to bring uniformity in the reporting of salivary gland FNAC and improve the clinic-pathologic communication resulting in better patient management. The aim of the present study was to assess the application of the MSRSGC on FNAC specimens of salivary gland lesions at a tertiary care hospital.

Material and Methods:

All salivary gland aspiration cytology cases along with histopathology follow-up of salivary gland lesions, wherever available, over a period of 36 months were analyzed and re-categorized according to MSRSGC into six categories and the risk of malignancy (ROM) was computed.

Results:

Of the 123 patients, 23 (18.69%) were classified as non-diagnostic, 39 cases (31.7%) as non-neoplastic, one (0.81%) as atypia of undetermined significance (AUS), benign neoplasm in 49 (39.8%) cases, uncertain malignant potential in two cases (1.63%), suspicious of malignancy in two cases, and malignant in seven cases (5.69%). Out of 123 cases, histopathological correlation was available in 34 cases, for which the ROM was calculated. The ROM was 0% for non-neoplastic, 11.1% for benign neoplasm, and 100% each for salivary neoplasm of uncertain neoplastic potential, and 100% for malignant categories.

Conclusion:

In the present study, the distribution of cases according to MSRSGC was comparable with the previous studies. The proportion of cases classified as AUS was within the goal set by MSRSGC at less than 10%. A risk-based stratification of salivary gland lesions in the form of MSRSGC is essential in the present era to guide and alert the clinician about the subsequent management plan and convey the ROM.

Accuracy of parotid gland FNA cytology and reliability of the Milan System for Reporting Salivary Gland Cytopathology in clinical practice

Background

Differentiating between malignant and benign salivary gland tumors with fine‐needle aspiration cytology (FNAC) can be challenging. This study was aimed at testing the validity of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and at assessing possible differences in the sensitivity and specificity of parotid gland FNAC between dedicated head and neck (H&N) centers, subdivided into head and neck oncology centers (HNOCs) and head and neck oncology affiliated centers (HNOACs), and general hospitals (GHs).

Methods

The Dutch Pathology Registry (PALGA) database was searched for patients who had undergone a salivary gland resection between January 1, 2006, and January 1, 2017, and had a preoperative FNAC result. The FNAC reports were retrospectively assigned to MSRSGC categories. The risk of malignancy (ROM) was calculated for each category. The sensitivity and specificity for diagnosing malignancy were calculated and compared among HNOCs, HNOACs, and GHs.

Results

In all, 12,898 FNAC aspirates were evaluated. The ROMs for each category were as follows: 12.5% in MSRSGC I, 10.3% in MSRSGC II, 29% in MSRSGC III, 2.3% in MSRSGC IVa, 28.6% in MSRSGC IVb, 83% in MSRSGC V, and 99.3% in MSRSGC VI. The sensitivity of FNAC was highest in HNOCs (88.1%), HNOACs scored lower (79.7%), and GHs had a sensitivity of 75.0%.

Conclusions

The MSRSGC is a valid tool for reporting parotid gland FNAC; therefore, these results strongly advocate its use. On the basis of the higher sensitivity of FNAC in dedicated H&N centers, the authors recommend that GHs use the presented management strategies to help to minimize the chances of a preoperative misdiagnosis.

The Milan System for Reporting Salivary Gland Cytopathology is a valid tool for reporting parotid gland fine‐needle aspiration cytology. The sensitivity of fine‐needle aspiration cytology is higher at dedicated head and neck centers.

Contribution of small tissue biopsy and flow cytometry to preoperative cytological categorization of salivary gland fine needle aspirates according to the Milan System: Single center experience on 287 cases

BACKGROUND

Milan system for reporting salivary gland cytopathology (MSRSGC) was proposed to provide a standardized reporting system for salivary gland fine needle aspiration biopsies. Modified Menghini type semi-automatic aspiration biopsy needles provide small tissue fragments (STFs), as well as cellular smears, and immunohistochemical and molecular studies can be performed using the STFs.

AIMS

We aimed to evaluate the contribution of STFs and ancillary techniques to pre-operative diagnosis of salivary gland lesions.

MATERIALS AND METHODS

In this study, smears of 287 cases with histopathological correlation were re-reviewed and assigned to one of the MSRSGC categories. In the second step, histopathological and immunohistochemical findings in STFs were evaluated together with cytological findings. Final diagnoses were obtained with the inclusion of flow cytometry (FC) results when available. Risk of malignancy (ROM) was calculated for each diagnostic category.

RESULTS

In the evaluation based on smears, a specific diagnosis could be obtained in 64.8% of the cases. ROMs were 0% for nondiagnostic (ND), 5.6% for non-neoplastic (NN), 55% for atypia of undetermined significance (AUS), 0.6% for benign neoplasm (BN), 27.8% for salivary gland neoplasm of uncertain malignant potential (SUMP), and 100% for suspicious for malignancy (SFM) and malignant (M) categories. With the addition of histopathological and immunohistochemical findings and FC results, a specific diagnosis could be obtained in 75.2% of the cases. ROMs were 0% for ND, 4.5% for NN, 53.8% for AUS, 0.6% for BN, 0% for SUMP, and 100% for SFM/M categories.

CONCLUSIONS

STFs contribute correct categorization of salivary gland lesions. The major contribution of ancillary methods is in the SUMP category.

The cytology of salivary gland neoplasms with globules of extracellular matrix: Case-based review of adenoid cystic carcinoma and its potential mimics

Fine needle aspiration (FNA) cytology is an important tool for diagnosing salivary gland neoplasms and for guiding clinical management. The classic adenoid cystic carcinoma (AdCC) is a basaloid neoplasm with abundant extracellular matrix. The presence globules of extracellular matrix are quite characteristic of AdCC but not diagnostic. We selected from our files six FNA cases that contained at least some globules of amorphous matrix that are similar to the ones seen in AdCC. The aim of this case-based review is to discuss the pitfalls and some of the common differential diagnoses of AdCC in FNA cytology. By the end of this review, we hope to have shared with the readers the lessons we learned from these cases and to highlight the key criteria needed to make a correct diagnosis of AdCC based on cytomorphology. The importance of considering other entities, in addition to AdCC, whenever a salivary gland FNA presents with globules is emphasized.

Application of the Milan System for Reporting Salivary Gland Cytopathology: A 10-Year Experience in a Single Japanese Institution

OBJECTIVE

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a recently published evidence-based categorization system for salivary gland fine-needle aspiration (FNA). We applied MSRSGC to Japanese cases and evaluated its utility.

STUDY DESIGN

A total of 480 FNA cases were reviewed. We recategorized each case into one of the MSRSGC categories. The risk of neoplasm (RON) and the risk of malignancy (ROM) for each diagnostic category in MSRSGC, and the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for malignancy and for neoplasms were calculated for cases with histological follow-up. In addition, the overall ROM (O-ROM) was calculated for all FNA cases.

RESULTS

RON, ROM, and O-ROM rates were as follows - non-diagnostic: 51.3, 5.1, and 1.0%; non-neoplastic: 0, 0, and 0%; atypia of undetermined significance: 83.9, 12.9, and 7.3%; neoplasm, benign: 100, 0, and 0%; salivary gland neoplasm of uncertain malignant potential: 100, 32.1, and 23.7%; suspicious for malignancy: 100, 85.7, and 60%; and malignant: 100, 100, 81.8%. The sensitivity, specificity, and accuracy with (without) indeterminate cases for malignancy were 65 (100), 99 (99), 92% (99%) and PPV and NPV were 96 and 100%, respectively, and those for neoplasms were 84 (100), 100 (100), 85% (100%), and PPV and NPV were 100 and 100%, respectively.

CONCLUSIONS

The MSRSGC is useful for stratification of ROM and for promoting the performance of salivary gland FNA. The MSRSGC could be easily introduced in Japan and may improve the Japanese salivary gland FNA status.

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.

Application of the Milan System for Reporting Salivary Gland Cytopathology: Experience of an academic institution in a tertiary academic medical center

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) represents a standardized reporting system for salivary gland lesions. The recent literature has demonstrated a wide range of data regarding range of malignancy (ROM) and interobserver variability. The objective of the current study was to evaluate the reproducibility and interobserver agreement of MSRSGC, and establish the ROM in a unique patient population residing within a designated Health Professional Shortage Area.

METHODS

A total of 380 salivary gland fine-needle aspiration cases were obtained over a 3-year period. Corresponding cytology reports and slides were reviewed in a blinded fashion by a panel of cytopathologists and recategorized using MSRSGC. ROM was calculated by cytohistologic correlation in 176 cases. Agreement between review of reports and slides and interobserver reliability were determined using kappa statistics.

RESULTS

The ROMs per MSRSGC category based on review of reports and slides were as follows: 4% and 0%, respectively, for nonneoplastic; 22% and 0%, respectively, for nondiagnostic; 42.9% and 48%, respectively, for atypia of undetermined significance; 1.6% and 1.9%, respectively, for benign-neoplastic; 17.9% and 15.6%, respectively, for salivary gland neoplasm of uncertain malignant potential; 81.8% and 71.4%, respectively, for suspicious for malignancy; and 100% and 90.5%, respectively, for malignant. There was a 59.2% overall agreement between review of reports and slides with regard to recategorizing salivary gland lesions (kappa, 0.51). The interobserver reliability demonstrated a 64.6% agreement (weighted kappa, 0.59).

CONCLUSIONS

The ROMs at the study institution appeared comparable to those in the published literature. There was moderate overall agreement among cytopathologists and low interobserver agreement with regard to the indeterminate categories. Image-guided fine-needle aspiration specimens; rapid onsite adequacy; and integration of clinical, imaging, and ancillary studies can improve diagnostic accuracy among indeterminate lesions.

The Milan system for reporting salivary gland cytopathology: A comprehensive review of the literature

BACKGROUND

The Milan system for Reporting Salivary Gland Cytopathology (MSRSGC) was published in 2018. Since then, many authors have published their institutional experience by retrospectively assigning salivary gland fine-needle aspiration cases to each of the MSRSGC categories and calculated their risk of malignancy (ROM) accordingly.

METHODS

We reviewed all published articles available online in English that used the MSRSGC since or near its publication. We calculated the risk of neoplasm and ROM for each diagnostic category. In addition, the false-negative and false-positive rates from all studies were examined.

RESULTS

Thirty-seven articles were identified in the English literature; 2 were published in 2017, 14 in 2018, 18 in 2019, and 3 in 2020. The total number of cases was 16 394, and 8 468 had surgical follow-up. The mean ROM was 16.9% for category I, 10.5% for category II, 39.3% for category III, 2.9% for category IVa, 39.4% for category IVb, 84.2% for category V, and 97.5% for category VI. The mean false-negative rate for MSRSGC categories II and IVa was 4.5%. Similarly, the mean false-positive rate for MSRSGC categories V and VI was 5.1%.

CONCLUSION

A tiered classification scheme of MSRSGC is helpful in effectively guiding clinical management of patients with salivary gland lesions. The reported mean ROM for each category in most studies is within the recommended range published by the MSRSGC.

Current classification systems and standardized terminology in cytopathology

The history of classification systems and the search for a unified nomenclature in cytopathology spans several decades and expresses the preoccupation of all those involved to make cytopathology a reliable diagnostic tool and a trusted screening method. Early classification schemes, applicable to exfoliative and aspiration cytology, attempted to set some basic standards for how non-gynecological cytopathology findings should be reported. While useful in establishing some basic guidelines, these were not specific to the various fields of non-gynecologic cytopathology, often burdened with specific problems. Cytopathology has evolved tremendously in the last couple of decades, undoubtedly boosted by the emergence of various classification schemes that, more than ever, are based on evidence gathered by professionals across the globe. The benefit of classification systems and standardized nomenclature in cytopathology is to provide useful, clear, and clinically relevant information for clinicians and ultimately to provide the best patient care. Standardized reporting systems make cytopathology reports more meaningful and robust. It now became standard that these include by default elements, such as adequacy criteria, diagnostic groups, risk of malignancy (ROM), and recommendations for patient management. In this brief review, we attempted to summarize how these classification schemes emerged and how they are reshaping the landscape of diagnostic cytopathology.

A multicenter validation of the revised version of the Milan system for reporting salivary gland cytology (MSRSGC)

INTRODUCTION

Fine-needle aspiration cytology (FNAC) is a basic step in the diagnosis of salivary gland tumors that have a wide variety of histological types. The recent Milan system for reporting salivary gland cytopathology (MSRSGC) can correlate the risk of malignancy with precise cytological features. A revised version was recently proposed to improve the surgical relevance and facilitate uniform management.

MATERIAL AND METHODS

A multicenter study retrospectively used the original and revised MSRSGC criteria to classify a series of patients who received surgery after FNAC.

RESULTS

We enrolled 503 patients from three tertiary centers. The risk of malignancy for the MSRSGC resulted 19.5% in cat. I, 14.3% in cat. II, 17.6% in cat. III, 3.6% in cat. IVa, 24.6% in cat. IVb, 66.7% in cat. V, and 96.8% in cat. VI. The results from the revised MSRSGC were consistent with the original values.

CONCLUSION

The MSRSGC is a promising classification system. In our opinion, the revised version of the MSRSGC supplements FNAC with some crucial clinical information and can better identify the appropriate treatment in each category.

Salivary gland fine-needle aspiration cytology with the application of the Milan system for risk stratification and histological correlation: A retrospective 6-year study

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is based on risk stratification. We presented our experience with fine-needle aspiration cytology (FNAC) for the diagnosis of salivary glands lesions by applying the MSRSGC categorization to the cytological diagnoses, and determined risk of malignancy (ROM) for each category.

METHODS

Fine-needle aspiration cytology of salivary gland lesions performed over a 6-year period was retrieved. FNAC results were retrospectively categorized according to the MSRSGC criteria, and correlated with corresponding histologic follow-up. ROM for each diagnostic category was calculated.

RESULTS

A total of 208 FNAC of salivary gland lesions were reviewed and retrospectively categorized as: non-diagnostic (ND) 23 (11%), non-neoplastic (NN) 54 (26%), atypia of undetermined significance (AUS) 10 (4.8%), benign neoplasms (BN) 77 (37%), salivary gland of uncertain malignant potential (SUMP) 13 (6.3%), suspicious for malignancy (SM) 7 (3.4%), and malignant (M) 24 (11.5%). Histopathological follow-up was available for 84 of 208 cases (40.4%). Overall concordance rate between FNAC and histology was 78.8%. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated as 93.3%, 94.6%, 82.4%, and 98.2%, respectively. Diagnostic accuracy to distinguish benign from malignant disease was 94.4%. ROM for each category was ND 0%, NN 0%, AUS 75%, BN 2.2%, SUMP 28.6%, SM 50%, and M 100%.

CONCLUSION

Fine-needle aspiration cytology continues to be an accurate diagnostic tool for most salivary gland neoplasms showing classical morphologic features. However, difficult cases with unusual or overlapping features will occur. In these situations, the use of MSRSGC risk-stratification could be helpful to define appropriate management.

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.

Fine-needle aspiration cytology in the diagnosis of salivary gland lesions. The role of the Milan system for reporting cytopathology

BACKGROUND

Fine needle aspiration cytology (FNAC) is an established technique in the management of salivary gland lesions. The Milan System for reporting salivary gland cytopathology (MSRSGC) intents to standardize diagnostic categories. Current studies are trying to evaluate the diagnostic approach of this system.

METHODS

FNAC of salivary gland lesions were retrieved over an 11-year period. 185 FNAC specimens from 182 patients were reviewed blindly and classified according to the criteria established by the MSRSGC. 136 (74.7%) patients had follow-up of their processes.

RESULTS

The total number of diagnostic categories and risk of malignancy (ROM) in 185 specimens were the following: non-diagnostic 39 (21.1%; ROM 12%), non-neoplastic 35 (18.9%; ROM 0%), atypia of undetermined significance (AUS) 17 (9.2%; ROM 46.1%), benign neoplasm 75 (40.5%; ROM 4.9%), salivary gland neoplasm of uncertain malignant potential 4 (2.2%; ROM 100%), suspicious for malignancy 7 (3.8%; ROM 100%), malignant 8 (4.3%; ROM 100%). No false positives were observed in groups IVb, V, and VI in this series. The overall sensitivity, specificity, negative predictive value, positive predictive value and diagnostic accuracy were 88%, 91.8%, 96.3%, 76.7%, and 91% respectively.

CONCLUSION

The ROM reported in our study was in keeping with ROM published by the MSRSGC. This system provides standardized information for risk stratification. The category AUS encompassed cases causing uncertainty representing a challenge in management. Defining criteria for AUS category need to be refined. The system facilitates communication between pathologists and clinicians favoring improvement in patient care.

The Milan system for reporting salivary gland cytology: A retrospective analysis of 1384 cases in a tertiary Southeast Asian institution

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) aims to provide a common language for risk stratification and management. We examine the incidence of MSRSGC categories and the corresponding risk of malignancy (ROM) within a tertiary referral centre in Southeast Asia.

METHODS

Salivary gland fine needle aspirations (FNAs) performed within a 10-year period were classified retrospectively according to the MSRSGC. Cytohistologic correlation was performed. The results were compared with the existing literature, including Asian and Western studies.

RESULTS

A total of 1384 salivary gland FNAs were evaluated, 421 with corresponding histology. The category distribution was: nondiagnostic, 28.9%; nonneoplastic, 18.0%; atypia of undetermined significance (AUS), 9.8%; benign neoplasm, 32.9%; salivary gland neoplasm of uncertain malignant potential (SUMP), 5.7%; suspicious for malignancy, 1.6%; and malignant, 3.2%. The ROMs were: nondiagnostic, 10.0%; nonneoplastic, 17.5%; AUS, 29.5%; benign neoplasm, 0.5%; SUMP, 17.1%; suspicious for malignancy, 83.3%; and malignant, 100.0%. Our relatively high nondiagnostic rate likely reflects preanalytical factors, whereas our low malignancy rate may be related to population and health care accessibility. Our nonneoplastic ROM was 17.5% compared with 5% to 10% in the literature, likely due to the relatively small number of excised cases; the ROM for SUMP was 17.1% versus 21% to 44% in the literature, possibly reflecting a significant proportion of benign basaloid neoplasms on histology. Interestingly, all false-negative cases in the nonneoplastic category were lymphoid-rich lesions.

CONCLUSION

This is one of the largest single-institution studies in the existing literature documenting both the incidence and ROMs of MSRSGC categories. We also highlight specific challenges surrounding lymphoid-rich lesions.

The Milan System at Memorial Sloan Kettering: Utility of the categorization system for in-house salivary gland fine-needle aspiration cytology at a comprehensive cancer center

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) provides a standardized reporting system for salivary gland fine-needle aspiration (SGFNA). We review the clinical utility of the MSRSGC at a tertiary care cancer center by assessing the rates of malignancy (ROM) among different categories.

METHODS

A retrospective search was performed to retrieve all SGFNA cases performed at our institution between 1/1/07 and 12/31/18. The initial primary diagnoses were recorded and cases were then assigned to appropriate MSRSGC categories. ROM was then calculated for all categories.

RESULTS

A total of 976 cases were identified, and 373 with follow-up. The ROM was 19.7% (192/976) for all-comers and 51.3% (192/374) among cases with follow-up. Using MSRSGC, SGFNA showed a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 65.6%, 87.4%, 100%, and 72.6%, respectively. ROM for MSRSGC categories I, II, III, IVa, IVb, V, and VI were 20.7%, 30.0%, 45.8%, 3.3%, 50.7%, 100%, and 100%, respectively. Utilizing MSRSGC resulted in a nondiagnostic rate of 14.4%. The nondiagnostic rate was lower when the procedure was performed by pathologists vs nonpathologists (12.9% vs 15.8%) but was comparable when rapid on site evaluation (ROSE) was performed (12.9% vs 11.6%).

CONCLUSION

In our patient population, MSRSGC resulted in a perfect PPV and moderate NPV. Utilizing MSRSGC results in a higher nondiagnostic rate due to the inclusion of cases with benign elements or cyst contents only in this category. Performing ROSE is more important in attaining an adequate sample than the specialty of the person performing SGFNA.

Fine-Needle Aspiration Cytology of Cellular Basaloid Neoplasms of the Salivary Gland

Context.—

Cellular basaloid neoplasms of the salivary gland represent a diverse group of benign and malignant neoplasms with significant cytomorphologic overlap on fine-needle aspiration cytology. All are marked by the presence of monotonous and usually bland basaloid epithelium. Distinction between basaloid neoplasms on fine-needle aspiration cytology is based on the presence or absence of additional features, including a second cell population (eg, myoepithelial cells), an acellular stromal component, and/or cytologic atypia within the basaloid epithelium. This review highlights the cytomorphologic features of the most common cellular basaloid neoplasms of the salivary gland, with an emphasis on classification and subclassification within the Milan System.

Objective.—

To provide a comprehensive review of the cytologic features of basaloid epithelial neoplasms of the salivary gland, with an emphasis on classification within the Milan System for Reporting Salivary Gland Cytopathology.

Data Sources.—

Peer-reviewed literature, recent textbooks, and personal experiences of the author.

Conclusions.—

Some basaloid neoplasms, in particular pleomorphic adenomas and adenoid cystic carcinomas, may have characteristic findings on fine-needle aspiration that allow for definitive diagnosis. In other cases, however, fine-needle aspiration can confirm a neoplastic basaloid process, but specific classification of a benign or malignant neoplasm cannot be rendered. The Milan System for Reporting Salivary Gland Cytopathology acknowledges this difficulty, and recommends benign or malignant classification only when definitive diagnostic features of a specific neoplasm are present. For indeterminate cases, the subcategorization of salivary neoplasm of uncertain malignant potential is recommended.

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.