Salivary gland tumor fine-needle aspiration cytology: a proposal for a risk stratification classification

Oncologic outcomes of the most prevalent major salivary gland cancers: retrospective cohort study from single center

BACKGROUND

The preoperative diagnosis of salivary gland cancer (SGC) is crucial for the application of appropriate treatment, particularly involving the extension of the resection.

METHODS

Retrospective search of medical database identified 116 patients treated surgically with malignant tumors of salivary gland between 2010 and 2020. Analysis included the demographical data, clinical course, type of surgical and adjuvant treatment, histology type and margin status, perivascular invasion (LVI), perineural invasion (PNI), metastatic lymph nodes (LN). Facial nerve function, recurrence-free and overall survival were evaluated. Adequate statistics were used for data analysis.

RESULTS

The final cohort included 63 SGC patients, with adenoid cystic carcinoma the most common pathological type (27%, n = 17), followed by adenocarcinoma (17.4% n = 11). T1 and T2 patients accounted for majority cases (n = 46). The lymph node metastases were confirmed with the histopathology in 31.7% (n = 20). Distant metastases were observed in 4.8% of cases (n = 3). 38% (n = 24) of SGC were treated selectively with surgery, 49.2% (n = 31) had postoperative radiotherapy and 15.9% (n = 10)-radio-chemotherapy. The final facial nerve function was impaired in 38% of patients. Mean overall survival (OS) for all patients was 108.7 (± 132.1) months, and was the most favorable for acinar cell carcinoma (118.9 ± 45.4) and the poorest for squamous cell carcinoma (44 ± 32). Cox regression analysis of disease-free survival and OS identified significant association only with patients' age over 65 years, the hazard ratio of 7.955 and 6.486, respectively.

CONCLUSIONS

The efficacy of treatment modalities for SGC should be verified with regard to the histopathological type, but also the patients' age should be taken into account.

How important are the cytomorphologic subtypes of the salivary gland neoplasm of uncertain malignant potential (SUMP) category in the Milan system for reporting salivary gland cytology? An institutional experience 2018-2024

INTRODUCTION

Salivary gland neoplasm of uncertain malignant potential (SUMP) is an important diagnostic category of the Milan System for reporting salivary gland cytology (MSRSGC). Further subcategorization by cytomorphologic subtypes has been recommended to risk-stratify cases. In this study, our institutional experience with the risk of neoplasm (RON) and risk of malignancy (ROM) based on cytomorphologic subcategorization of SUMP is reported. We also report the prevalence of malignancy (POM) at our institution.

METHODS

The pathology database was queried for cases of fine-needle aspiration (FNA) diagnosed as SUMP along with follow-up at our institution from 2018-February 2024. This study was approved by an institutional review board.

RESULTS

Of 1159 cases of salivary gland FNA specimens reported as per MSRSGC at our institution, 14.8% (171/1159 cases) were diagnosed as SUMP, with these reports verified by at least 16 cytopathologists. Surgical follow-up was available for 139/171 (81.3%) of these cases, for which the original cytomorphologic subgroups were as follows: 65 (46.8%) basaloid, 48 (34.5%) oncocytic/oncocytoid, 14 (10.1%) myoepithelial, 9 (6.5%) other, 2 (1.4%) clear cell, and 1 (0.7%) mucinous. The POM within SUMP at our institution is within a range of 29.8%-36.7%. When considering all cases, our institutional RON for SUMP was 97.8% (136/139), and the ROM was 36.7% (51/139). Notably, a significant portion of cases (36%, 50/139) underwent review at a daily intradepartmental consensus conference. Analysis revealed that SUMP cases that underwent consensus review had a ROM of 46% (23/50), versus 31.5% (28/89) in independently verified cases (p = .13). Of the cytomorphologic subgroups, basaloid SUMP in particular was more likely to be benign on resection when the case had been independently verified than after consensus review (p = .0082). When considering only the independently verified cases, the ROM for each subgroup was as follows: 38.7% (12/31) in oncocytic/oncocytoid, 20% (9/45) in basaloid, 33.3% (2/6) in myoepithelial, 60% (3/5) in "other", and 100% (1/1) in both mucinous and clear cell (p = .0407).

CONCLUSION

While the RON is high across all cytomorphologic subgroups of SUMP, the ROM does vary across the groups, with basaloid cytomorphology having the lowest ROM. This effect is seen in independently verified cases but not in cases having undergone consensus review.

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.

Molecular testing in salivary gland cytopathology: A practical overview in conjunction with the Milan system

Recently, significant advances in the molecular characterization of salivary gland neoplasms have facilitated the classification and diagnosis of specific diagnostic entities. In the highly challenging diagnostic scenario of salivary malignancies, molecular testing is increasingly being adopted in routine practice to refine the cytological diagnosis of salivary lesions. Here, we reviewed the most recent evidence in the field of salivary glands molecular cytopathology.

Second edition of the Milan System for Reporting Salivary Gland Cytopathology: Refining the role of salivary gland FNA

The use of standardised reporting systems for non-gynaecologic cytopathology has made enormous gains in popularity during the past decade, including for thyroid fine-needle aspiration, urine cytology, serous effusions, pancreas, lymph nodes, lung and more. In February 2018, the first edition of the Atlas of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was published. The MSRSGC defines six diagnostic fine-needle aspiration categories encompassing the spectrum of non-neoplastic, benign and malignant lesions of the salivary glands. The goal of the MSRSGC is to combine each diagnostic category with a defined risk of malignancy and a specific clinical and/or surgical management algorithm. Since its initial publication in 2018, more than 200 studies and commentaries have been published, confirming the role of the MSRSGC. The second edition of the MSRSGC, published in July 2023, includes refined risks of malignancy based on systematic reviews and meta-analyses, a new chapter summarising the use of salivary gland imaging, new advances in ancillary testing and updates in nomenclature.

Second edition of the Milan System for Reporting Salivary Gland Cytopathology: Refining the role of salivary gland FNA

The use of standardized reporting systems for nongynecologic cytopathology has made enormous gains in popularity during the past decade, including for thyroid fine-needle aspiration, urine cytology, serous effusions, pancreas, lymph nodes, lung, and more. In February 2018, the first edition Atlas of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was published. The MSRSGC defines six diagnostic fine-needle aspiration categories encompassing the spectrum of Non-Neoplastic, benign, and malignant lesions of the salivary glands. The goal of the MSRSGC is to combine each diagnostic category with a defined risk of malignancy and a specific clinical and/or surgical management algorithm. Since its initial publication in 2018, more than 200 studies and commentaries have been published confirming the role of the MSRSGC. The second edition of the MSRSGC, published in July 2023, includes refined risks of malignancy based on systematic reviews and meta-analyses, a new chapter summarizing the use of salivary gland imaging, new advances in ancillary testing, and updates in nomenclature. CONCISE SENTENCE: The second edition of the Milan System for Reporting Salivary Gland Cytopathology, published in July 2023, includes refined risks of malignancy based on systematic reviews and meta-analyses, a new chapter summarizing the use of salivary gland imaging, new advances in ancillary testing, updates in nomenclature, and a guide to the practical application of the latest ancillary markers for the diagnosis of selected salivary gland fine-needle aspiration cases.

Second edition of the Milan System for Reporting Salivary Gland Cytopathology: Refining the role of salivary gland FNA

The use of standardized reporting systems for non-gynecologic cytopathology has made enormous gains in popularity during the past decade, including for thyroid fine-needle aspiration, urine cytology, serous effusions, pancreas, lymph nodes, lung, and more. In February 2018, the first edition Atlas of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was published. The MSRSGC defines six diagnostic fine-needle aspiration categories encompassing the spectrum of non-neoplastic, benign, and malignant lesions of the salivary glands. The goal of the MSRSGC is to combine each diagnostic category with a defined risk of malignancy and a specific clinical and/or surgical management algorithm. Since its initial publication in 2018, more than 200 studies and commentaries have been published confirming the role of the MSRSGC. The second edition of the MSRSGC, published in July 2023, includes refined risks of malignancy based on systematic reviews and meta-analyses, a new chapter summarizing the use of salivary gland imaging, new advances in ancillary testing, and updates in nomenclature.

Application of the Milan System for Reporting Salivary Gland Lesions and Its Cytohistological Correlation for Risk Stratification: A Single-Institution Experience

INTRODUCTION

 Salivary gland tumors are known to have a heterogeneous profile with variable clinical presentation and a wide variety of histological subgroups of prognostic significance. Immunocytochemical markers that aid in the diagnosis and characterization of the cell type of origin are critical for this heterogeneous group of malignancies.

AIMS AND OBJECTIVES

To study the application of The 'Milan System' for Reporting Salivary Gland Cytology and the diagnostic utility of a panel of immunocytochemical markers in the diagnosis of salivary gland neoplasms and their cytohistological correlation for their risk stratification.

MATERIALS AND METHODS

This was a prospective study carried out in which a total of 60 patients were enrolled in the study. Fine-needle aspiration cytology (FNAC) smears and cell blocks were prepared with standard techniques and staining procedures. Immunocytochemistry (ICC) was performed on cell block sections by immunoperoxidase procedure. Immunocytochemical (ICC) stains were used for the differentiation of the lesions in cell blocks. Histopathology was also studied if the patient underwent excision of salivary gland lesions.

DISCUSSION AND RESULTS

Almost 60 cases were studied under FNAC and cell block evaluation, as well as ICC, among those five (8.33%) samples were inadequate, eight (13.3%) were non-neoplastic, 27 (45%) were benign, one (1.7%) was neoplasm with uncertain malignancy potential, one (1.7%) was suspected of malignancy, and 19 (31.7%) were malignant. The histopathological diagnosis was confirmed in 47 cases. Of these, 24 (51.1%) were benign and 23 (48.9%) were malignant. The malignancy rate for Milan Categories I, II, III, IVa, IVb, V, and VI was 0%, 0%, 100%, 24%, 50%, 80%, and 84.6%, respectively. The study showed that malignancy risk stratification could be further improved by using cell block with immunocytochemistry as a complementary diagnostic modality.

CONCLUSIONS

The present study was carried out to assess the usefulness of the Milan system to report salivary gland cytology results. Thus, the findings of the present study show that the Milan system is helpful in stratifying the risk of malignancy in salivary gland tumors.

Salivary gland neoplasms in small biopsies and fine needle aspirations

Salivary gland neoplasms are rare and represent a diverse group of head and neck tumors. Their diagnosis in limited cellularity specimens can be challenging as many of these have overlapping clinical, radiological presentation, and pathologic features. Fine needle aspiration and/or core biopsies are more of a norm than rarity to be performed preoperatively to provide invaluable information that can guide clinical management including surgery. Even though these limited specimens may not always provide a definitive diagnosis; they have high sensitivity in confirming primary neoplasia, assessing the tumor grade, and ruling out non-surgical disease. An algorithmic pattern based approach can help narrow the differential diagnosis; leading to a definitive diagnosis with the help of specific ancillary studies.

A systematic review on the role of biomarkers in liquid biopsies and saliva samples in the monitoring of salivary gland cancer

BACKGROUND

Salivary gland cancer is a rare disease, and approximately 20% of tumors in the salivary glands are malignant. Reliable biomarkers may have a role in monitoring salivary gland cancer.

AIM

To review the current literature on the role of biomarkers in liquid biopsies and saliva samples in the monitoring of salivary gland cancer.

MATERIALS AND METHOD

This study systematically reviewed the literature on studies detecting salivary gland cancer by biomarkers in liquid biopsies and saliva samples by systematically searching PubMed and Embase between 1 January 2013 and 7 March 2023.

RESULTS

Five studies covering 64 malignant cases of salivary gland cancer were included, which considered inflammatory biomarkers or markers of genetic material in either blood or saliva. In saliva, there were demonstrated elevations of CA-19-9 in malignant cases, and elevations of miRNA in malignant and benign cases. In blood, there were demonstrated elevations of IL-33 in malignant and benign cases, elevations of ctDNA in malignant cases, and elevations of CTC in malignant cases.

CONCLUSION AND SIGNIFICANCE

The studies indicate that there is potential in the detection method. The studies detecting genetic material by liquid biopsies showed the most promising results. At present, there is still progression to be made before the method can be implemented for diagnostic use.

Diagnosis and Management of Parotid Gland Cancer with Focus on the Role of Preoperative Fine-Needle Aspiration Cytology: A 10-Year-Long Retrospective Study with 5-Year Follow-Up

Introduction

Salivary gland cancers represent a rare heterogeneous group of neoplasms with complex clinicopathological characteristics and distinct biological behaviour. The appropriate diagnosis and management of parotid gland cancer are challenging and should be based on the clinical, imaging, cytological, and histological features. The present study analysed the use of preoperative fine-needle aspiration cytology (FNAC) and intraoperative frozen section (FS) to guide the appropriate surgical and postoperative treatment of parotid gland cancers.

Materials and Methods

We selected 48 patients with primary malignancy of the parotid gland surgically treated between 1 January 2008 and 30 June 2017 at the Maxillo-Facial Surgery Division, University Hospital of Parma, Italy. The patients had postoperative histological diagnosis of malignant parotid cancer and were followed up for longer than 5 years.

Results

The 48 patients included in this study had a mean age of 56.7 years. The most frequent type of parotid gland cancer was carcinoma ex pleomorphic adenoma (22.9%), followed by mucoepidermoid carcinoma (16.7%) and acinic cell carcinoma (14.6%). All 48 patients underwent preoperative FNAC: 29 (60.4%) and 19 (39.6%) were suggestive of malignant and benign lesions, respectively. In 31 patients, intraoperative FS was performed.

Discussion

Compared to previous studies, the present study showed significantly lower diagnostic sensitivity of FNAC for parotid gland cancers. The preoperative diagnostic accuracy for suspected malignant cases may be improved by repeat analysis of the cytological specimen by experts, preoperative core needle biopsy, and/or intraoperative FS analysis of the suspected mass.

Salivary gland fine-needle aspiration biopsy: quality assurance results from a tertiary cancer center

INTRODUCTION

Fine-needle aspiration biopsy (FNAB) plays a critical role in the management of patients with salivary gland lesions. A specific diagnosis can be difficult due to the wide range of lesions with overlapping morphologic features, potentially leading to interpretation errors. We analyzed the cytologic-histologic discrepancies identified in the quality assurance program of a major cancer center in cases of salivary gland FNAB and performed a root cause analysis.

MATERIALS AND METHODS

Salivary gland FNAB specimens performed during a 12-year period at a major tertiary cancer center were reviewed. The inclusion criteria for this study included FNAB cases of salivary glands with subsequent histologic or flow cytometry follow up. The cytologic diagnoses for these cases were recategorized according to the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) based on the original reports. The risk of neoplasm and malignancy based on the cases with subsequent resection or flow cytometry and the most common causes of discrepancy were analyzed.

RESULTS

The risk of neoplasm ranged from 41% to 99% and the risk of malignancy ranged from 22% to 99% among the different MSRSGC categories. Lymphoid and myoepithelial rich lesions were the most common miscategorized lesions using the MSRSGC. Reactive changes due to inflammation were associated with overcalls. The most common malignancy in the atypical category was mucoepidermoid carcinomas.

CONCLUSIONS

Myoepithelial and lymphoid rich lesions arising in the salivary gland are associated with a higher risk of misclassification. The use of category IVB in the MSRSGC is appropriate for lesions with abundant myoepithelial cells. Reactive atypia seen in sialadenitis was the most common feature associated with overcall.

A rare case of canalicular adenoma in the parotid gland: Highlighting diagnostic limitations of fine-needle aspiration

BACKGROUND

Canalicular adenoma is a rare, benign tumor of primarily salivary gland origin that presents mostly in the upper lip. However, there are only six reports in the English literature detailing canalicular adenoma of the parotid gland, none of which discuss discrepancy between preoperative cytology and surgical pathology. In this report, we present a rare case of parotid gland canalicular adenoma where preoperative ultrasound-guided fine-needle aspiration (USFNA) suggested malignancy. The patient was treated with deep lobe parotidectomy due to the FNA results and her multiple comorbidities. However, her tumor may have been treated with observation alone if canalicular adenoma had been suspected prior to surgery.

MAIN FINDINGS

A 59-year-old female with a history of heart and lung disease presented with a 1.6 cm well defined, enhancing lesion involving the superficial portion of the right parotid gland. This lesion was incidentally noted on CT angiography (CTA) of the neck and chest. The well-defined characteristics of this lesion on CT imaging suggested benign neoplasm. However, USFNA results were suggestive of a malignant parotid lesion. The patient subsequently underwent right deep lobe parotidectomy with facial nerve dissection and superficial musculoaponeurotic system (SMAS) rotational flap reconstruction. Surgical pathology and immunohistochemistry yielded a final diagnosis of benign canalicular adenoma.

CONCLUSIONS

USFNA diagnosis of CA is extremely difficult due to its low-grade neoplastic cells mimicking neoplastic cells in other benign and malignant tumors of the head and neck. FNA remains a useful tool for assessing malignancy risk, but the results always have some level of uncertainty and do not provide sufficient detail. Therefore, FNA results should be interpreted in concert with imaging and patients' medical history. Cytopathologists can also report salivary gland FNA results in a more uniform and detailed manner by utilizing the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC).

Fine-Needle Aspiration Cytology for Parotid Tumors

Fine-needle aspiration (FNA) cytology is widely used in clinical practice as a simple and minimally invasive test for parotid tumors that allows for preoperative estimation of benignancy and malignancy, histological type, and malignancy grade and can be performed on an outpatient basis. In recent years, cell blocks prepared with core needle biopsy (CNB) and liquid-based cytology (LBC) have increased the reliability of immunostaining and molecular biological testing, leading to improved diagnostic accuracy. In 2018, the Milan System for Reporting Salivary Gland Cytology was introduced, but it does not include malignancy grade or histological type, so we proposed the Osaka Medical College classification as a more clinically based cell classification that includes both types of information, and we have reported on its usefulness. This review gives an overview of the history and use of FNA and describes CNB and LBC and the two classification systems.

Multiplexed single-cell analysis of FNA allows accurate diagnosis of salivary gland tumors

Diagnosing salivary gland tumors (SGTs) through fine-needle aspiration (FNA) biopsies is challenging due to the overlapping cytomorphologic features between benign and malignant tumors. The authors developed an innovative, multiplexed cycling technology for the rapid analyses of single cells obtained from FNA that can facilitate the molecular analyses and diagnosis of SGTs. Antibodies against 29 protein markers associated with 7 SGT subtypes were validated and chemically modified via custom linker-bio-orthogonal probes (FAST). Single-cell homogenates and FNA samples were profiled by FAST cyclic imaging and computational analysis. A prediction model was generated using a training set of 151,926 cells from primary SGTs (N = 26) and validated on a separate cohort (N = 30). Companion biomarker testing, such as neurotrophic tyrosine receptor kinase (NTRK), was also assessed with the FAST technology. The FAST molecular diagnostic assay was able to distinguish between benign and malignant SGTs with an accuracy of 0.86 for single-cell homogenate samples and 0.88 for FNA samples. Profiling of multiple markers as compared to a single marker increased the diagnostic accuracy (0.82 as compared to 0.65-0.74, respectively), independent of the cell number sampled. NTRK expression was also assessed by the FAST assay, highlighting the potential therapeutic application of this technology. Application of the novel multiplexed single-cell technology facilitates rapid biomarker testing from FNA samples at low cost. The customizable and modular FAST-FNA approach has relevance to multiple pathologies and organ systems where cytologic samples are often scarce and/or indeterminate resulting in improved diagnostic workflows and timely therapeutic clinical decision-making.

Milan system for reporting salivary gland cytopathology: Adoption and outcomes in a community setting

BACKGROUND

Milan system for reporting salivary gland cytopathology (MSRSGC) was introduced to standardize reporting of salivary gland cytopathology.

METHODS

A retrospective review of ultrasound-guided fine needle biopsy of salivary gland lesions was performed between January 2018 and May 2021 at a community otolaryngology practice. Diagnostic accuracy and rate of diagnostic sialoadenectomy were calculated.

RESULTS

A total of 203 FNAs (fine needle aspiration) were performed in 184 patients. MSRSGC was utilized in 87/203 cytopathology reports, with a diagnostic accuracy of 84%. Descriptive reporting was used in 115 FNAs, with a diagnostic accuracy of 89% (p = 0.68). Sialoadenectomy rate was 41% for MSRSGC compared to 36% in descriptive cytopathology (p = 0.48).

CONCLUSIONS

MSRSGC is as accurate as descriptive cytopathology and the rate of diagnostic sialoadenectomy between both groups is similar in our community. The MSRSGC brings uniformity and standardization to the FNA reporting process.

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.

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.

Salivary duct carcinoma: A report of 70 FNA cases and review of the literature

BACKGROUND

Although usually recognized as malignant, fine-needle aspiration (FNA) biopsy of salivary duct carcinoma (SDC) has been confused with other primary salivary gland (SG) neoplasms. This article undertook an analysis of a large collection of SDC FNA cases to assess diagnostic accuracy, specificity, and cytopathology.

METHODS

Cytopathology files were searched for SDC with histopathologic validation. FNA biopsy smears were performed using standard techniques.

RESULTS

Seventy cases from 56 patients (M:F, 1.9:1; age range, 26-92 years; mean age, 65 years) met inclusion criteria. All had tissue confirmation of SDC. FNA sites included: parotid gland (42, 60% cases), neck (10), submandibular gland (7), pre-/post-auricular area (5), face/cheek (3), mediastinal lymph nodes (2), and clavicle (1). Aspirates were from primary (52, 74%), metastatic (12, 17%), and locally recurrent (6, 9%) neoplasms. FNA diagnoses included: SDC (19, 27%), favor/suspicious for SDC (7, 10%), high-grade carcinoma (11), adenocarcinoma (9), carcinoma (6), malignant (6), SG neoplasm (5), atypia (3), SDC versus another malignancy (2), and pleomorphic adenoma (2). Large polygonal cells in groups and single forms showed cribriforming, variable necrosis, pseudopapillae, and oncocytic change. Androgen receptor staining was positive in all cases.

CONCLUSIONS

FNA biopsy is accurate and reliable in classifying SDC as a malignant neoplasm, but much less so for identification as a specific tumor type. Using the Milan system, 86% of aspirates were classified as either malignant or suspicious for malignancy. A recurring pitfall includes sampling error in cases of SDC ex pleomorphic adenoma.

Ancillary studies on cell blocks from fine needle aspiration specimens of salivary gland lesions: A multi‐institutional study

Background

Ancillary studies are commonly performed on cell blocks prepared from fine‐needle aspiration (FNA) specimens. There are limited studies in application of ancillary studies on cell blocks from salivary gland (SG) FNAs. This multi‐institutional study evaluates the role of ancillary studies performed on cell blocks in the diagnosis of SG lesions, and their impact on clinical management.

Method

The electronic pathology archives of three large academic institutions were searched for SG FNAs with ancillary studies performed on cell blocks. The patient demographics, FNA site, cytologic diagnosis, ancillary studies, and surgical follow‐up were recorded. If needed, the cytologic diagnoses were reclassified as per the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC).

Results

117 SG FNA cases were identified including 3, 10, 11, 6, 23, 4, and 60 cases in MSRSGC categories I, II, III, IVa, IVb, V, VI, respectively with surgical follow‐up available ranging from 27% to 100% within each category. Ancillary studies including histochemistry, immunocytochemistry (IHC), and in situ hybridization (ISH) were beneficial in 60%–100% of cases in each category. Risk of malignancy was 100% in both the suspicious for malignancy (V) and malignant (VI) categories. Ancillary studies improved diagnosis in 60% of non‐neoplastic cases (II, 6/10), 100% of benign neoplasm cases (IVa, 6/6), and 98.3% of malignant cases (VI, 59/60).

Conclusion

Judicious and case‐based ancillary studies performed on SG FNA cell blocks with sufficient material can improve the diagnostic yield by further characterization of the atypical/neoplastic cells, particularly in MSRSGC categories IVa‐VI.

Glial Fibrillary Acidic Protein Expression Helps Distinguish Pleomorphic Adenoma from Histologic Mimics

Pleomorphic adenoma (PA) is the most common biphasic type of salivary gland tumour to arise in adults. It is a biphasic tumour composed of both luminal (ductal) cells and abluminal (basal and myoepithelial) cells. Other biphasic salivary gland type tumours, both benign and malignant, can mimic PA, especially on small biopsies. Previous studies have shown that glial fibrillary acidic protein (GFAP) is preferentially expressed in PA and can be useful in the distinction from other salivary gland tumours. However, most of these studies were performed on a small subset of tumour types at a time when the classification of salivary gland type tumours was less refined. The purpose of this study was to assess the expression of glial fibrillary acidic protein (GFAP) in a broad group of both benign and malignant salivary gland tumours. The expression of GFAP was assessed in 99 tumours including 54 PAs, 5 basal cell adenomas, 1 myoepitheliomas, 5 adenoid cystic carcinomas, 6 epithelial-myoepithelial carcinomas (EMCA), 6 mucoepidermoid carcinomas, 7 salivary duct carcinomas, 1 adenocarcinomas NOS, 2 myoepithelial carcinomas, 4 basal cell adenocarcinomas, 5 acinic cell carcinomas and 3 polymorphous adenocarcinomas. Of the malignant cases, 8 were classified as carcinomas ex PA. GFAP was also assessed in 19 concurrent biopsy specimens. GFAP was expressed in the resections of 51 PAs examined (94%). Expression was predominantly strong and diffusely seen in myoepithelial cells. Strong and diffuse GFAP expression was also seen in two EMCAs (33%) and one myoepithelial carcinoma (50%). On biopsy specimens, 100% of PAs and basal cell adenomas expressed GFAP. GFAP was also seen in 1 out of 3 carcinomas ex PAs on biopsies. Almost all PAs show strong and diffuse expression of GFAP. In contrast, most malignant neoplasms that can mimic PA on biopsies show only rare, focal expression. Other benign tumours composed of abluminal/myoepithelial cells also show focal expression of GFAP, highlighting the spectrum these tumours share with PA. Overall, the presence of strong and diffuse GFAP expression can favour a benign neoplasm, specifically a PA, on limited biopsy specimens.

NR4A3 Immunostain Is a Highly Sensitive and Specific Marker for Acinic Cell Carcinoma in Cytologic and Surgical Specimens

OBJECTIVES

Salivary gland acinic cell carcinoma (AciCC) has recognizable cytomorphologic features that can overlap with benign and malignant entities, creating a diagnostic challenge. AciCC harbors a t(4;9) translocation increasing nuclear receptor subfamily 4 group A member 3 (NR4A3) expression, detectable by immunohistochemistry (IHC) on surgical resection (SR). NR4A3 IHC cytology data are limited. Here, we examine NR4A3 IHC on smears, cell blocks (CBs), and SRs of AciCC and its mimickers.

METHODS

Our cohort comprised AciCC (including high-grade transformation), secretory carcinoma, mucoepidermoid carcinoma (MEC), Warthin tumor, pleomorphic adenoma (PA), cellular PA, carcinoma ex-PA, oncocytic carcinoma, oncocytoma, and nodular oncocytosis. NR4A3 IHC (Santa Cruz Biotechnology and Origene antibodies) was positive if more than 5% tumor cells showed nuclear staining.

RESULTS

Among CBs, 90% of AciCC cases and none of the mimickers expressed NR4A3. Among SRs, 100% of AciCC cases showed diffuse NR4A3, whereas one high-grade MEC expressed focal NR4A3. Concordance was 95% with two antibody clones. Sensitivity, specificity, positive predictive value, and negative predictive value were 90%, 100%, 100%, and 94.7% for CBs and 100%, 98.8%, 92.3%, and 100% for SRs, respectively. NR4A3 immunostaining was demonstrable on smears from an AciCC case.

CONCLUSIONS

NR4A3 IHC can be a robust diagnostic tool to identify AciCC, especially for cytology specimens.

Fine-Needle Aspiration Cytology of Salivary Gland Tumors Before the Milan System: Ten Years of Experience at a Tertiary Care Center in Turkey

Objective

The role of fine-needle aspiration cytology (FNAC) is well established for preoperative evaluation of patients with salivary gland lesions. However, the lack of a uniform system for salivary gland FNAC has limited its effectiveness. In recent years, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has been in use around the world to report the cytology results. We aimed to investigate the efficacy and accuracy of FNAC examined according to pre-MSRSGC era dichotomous benign/malignant classification in salivary gland tumors.

Methods

Patients who underwent surgery between January 2011 and December 2020 due to major salivary gland tumors were retrospectively analyzed. Two hundred and four patients were included in the analysis. Preoperative FNAC results and final histopatological diagnoses were grouped as benign or malignant. Final histopatological diagnoses were compared with the preoperative FNAC results. Also, sensitivity, specificity, and accuracy of the preoperative FNAC results, as well as the agreement between both tests were investigated.

Results

The sensitivity, specificity, accuracy, positive and negative predictive values of the preoperative FNAC for the diagnosis of malignancy were 59.09%, 97.85%, 93.75%, 76.47%, and 95.29%, respectively. There was a moderate agreement between the preoperative FNAC results and final histopatological diagnoses.

Conclusion

The accuracy of the preoperative FNAC and the information given about malignancy risk are the most important criteria for patient management and decision-making. The MSRSGC, which consists of a six-tiered classification rather than a dichotomous "yes/no" system, may contribute to patient management and decision-making by increasing the efficacy and accuracy of FNAC.

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.

Risk stratification by application of Milan system for reporting salivary gland cytopathology: A tertiary care experience

Objectives:

The Milan system for reporting salivary gland cytopathology (MSRSGC) classification has been proposed to improve reproducibility in the management of salivary gland lesions. Fine-needle aspiration cytology (FNAC) is a widely accepted, well-tolerated, cost-effective, minimally invasive diagnostic method for pre-operative evaluation of salivary gland lesion that aids management decisions. The present study aims to reclassify the salivary gland FNAC aspirates by applying MSRSGC and calculating the risk of neoplasm and malignancy for each diagnostic category.

Material and Methods:

The present study is a retrospective observational study done for 54 months. A total of 168 cases of salivary gland FNA, 54 cases were excised in our institute for histopathology. Retrospective reviews were performed, and the FNAC cases were reclassified according to the Milan system, and the results of FNAC and final histology were correlated, wherever available. Furthermore, the risk of malignancy was calculated for all the diagnostic categories. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy (DA) of FNAC were determined.

Results:

In the present study, the age of patients ranged from 3 to 86 years, with a mean age of 39 years. Among all the patients, 61.3% were male, and 38.6% were female. However, only 54 salivary gland FNA samples for which histopathology was available were categorized into six categories. Among them, category IV (neoplastic) had a maximum number of cases of 66.6%. The rate of malignancy was calculated for all diagnostic categories as follows: (1) Non-diagnostic: 0.0%, (2) non-neoplastic 0.0%, (3) atypia of undermined significance 100%, (4a) benign 5.5%, (4b) uncertain malignant potential 33.33%, (5) suspicious for malignancy 00%, and (6) malignancy 80%. The sensitivity, specificity, PPV, NPV, and DA for differentiating between benign and malignant neoplasm were 36.3%, 94.4%, 66.6%, 82.9%, and 80%. Two false-positive and seven false-negative neoplastic cases were noted.

Conclusion:

FNAC is a reliable, minimally invasive diagnostic method with high DA for diagnosing salivary gland lesions. Most salivary gland lesions can be accurately diagnosed on FNAC with adequate sampling and cytopathologists experience.

2021 Update on Diagnostic Markers and Translocation in Salivary Gland Tumors

Salivary gland tumors are a rare tumor entity within malignant tumors of all tissues. The most common are malignant mucoepidermoid carcinoma, adenoid cystic carcinoma, and acinic cell carcinoma. Pleomorphic adenoma is the most recurrent form of benign salivary gland tumor. Due to their low incidence rates and complex histological patterns, they are difficult to diagnose accurately. Malignant tumors of the salivary glands are challenging in terms of differentiation because of their variability in histochemistry and translocations. Therefore, the primary goal of the study was to review the current literature to identify the recent developments in histochemical diagnostics and translocations for differentiating salivary gland tumors.

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, from Its Introduction to Its Current Adoption in the Diagnosis of Salivary Gland Cytology

Salivary gland masses are often encountered in the everyday practice of cytopathology. It is commonly known that the cytologic interpretation of these lesions can pose diagnostic problems due to overlapping cytomorphologic features. Fine needle aspiration (FNA) of salivary lesions shows good to excellent sensitivity and specificity in differentiating a neoplastic from a non-neoplastic process and in diagnosing common tumors such as pleomorphic adenoma. However, its value is limited in diagnosing specific neoplastic entities especially those with well-differentiated morphology. In light of this gap, an international group of pathologists has proposed a management-oriented, tiered classification for reporting salivary gland FNA specimens, “The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC)”. Similar to other classification systems, the MSRSGC scheme comprises six diagnostic categories, which were linked with a specific risk of malignancy (ROM) and management. In this review article, the author evaluated the published literature on FNA in diagnosing salivary gland lesions with the adoption of the Milan system since its introduction in the daily practice of salivary cytopathology.

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.

Management of Salivary Gland Malignancy: ASCO Guideline

PURPOSE

To provide evidence-based recommendations for practicing physicians and other healthcare providers on the management of salivary gland malignancy.

METHODS

ASCO convened an Expert Panel of medical oncology, surgical oncology, radiation oncology, neuroradiology, pathology, and patient advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2000 through 2020. Outcomes of interest included survival, diagnostic accuracy, disease recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 293 relevant studies to inform the evidence base for this guideline. Six main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate radiotherapy techniques, the role of systemic therapy, and follow-up evaluations.

RECOMMENDATIONS

When possible, evidence-based recommendations were developed to address the diagnosis and appropriate preoperative evaluations for patients with a salivary gland malignancy, therapeutic procedures, and appropriate treatment options in various salivary gland histologies.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Analysis of the risk of malignancy associated with the basaloid and oncocytic subtypes of the salivary gland neoplasm of unknown malignant potential (SUMP) category in the Milan system

BACKGROUND

The salivary gland neoplasm of unknown malignant potential (SUMP) category reflects the cytomorphologic overlap and complexity of reporting salivary gland cytology in the Milan system. It includes neoplasms for which a diagnosis of a specific entity cannot be made and, more importantly, for which a carcinoma cannot be entirely excluded. For risk stratification, the subcategorization of SUMP based on the predominant cell type is recommended. This study was aimed at evaluating the risk of neoplasm (RON) and the risk of malignancy (ROM) of the basaloid and oncocytic subtypes of the SUMP category.

METHODS

A retrospective analysis of 482 salivary gland fine-needle aspirations from 2012 to 2019 resulted in 48 SUMP cases. The cytology of these cases was reviewed and reclassified as the basaloid or oncocytic subtype. Surgical follow-up was available for 36 cases. The RON and ROM for each subtype were calculated.

RESULTS

The RON and ROM were 100% and 23%, respectively, for monomorphic basaloid tumors and 88% and 58.8%, respectively, for monomorphic oncocytic tumors. The ROM for basaloid tumors was 8.3% without matrix/with minimal matrix and 60% with an nonfibrillary matrix. The ROM for oncocytic tumors was 50% without a cystic background and 60% with a cystic or mucinous background. The difference was not statistically significant for either of the subgroups.

CONCLUSIONS

Even though statistically not significant in our study, the differential ROMs within the oncocytic and basaloid subgroups help in the risk stratification of SUMP cases. Further subcategorization based on the stroma and background helps in limiting the differential diagnosis but does not necessarily add to the value of the risk stratification.

A triple-classification radiomics model for the differentiation of pleomorphic adenoma, Warthin tumour, and malignant salivary gland tumours on the basis of diffusion-weighted imaging

AIM

To develop and validate a triple-classification radiomics model for the preoperative differentiation of pleomorphic adenoma (PA), Warthin tumour (WT), and malignant salivary gland tumour (MSGT) based on diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

Data from 217 patients with histopathologically confirmed salivary gland tumours (100 PAs, 68 WTs, and 49 MSGTs) from January 2015 to March 2019 were analysed retrospectively and divided into a training set (n=173), and a validation set (n=44). A total of 396 radiomic features were extracted from the DWI of all patients. Analysis of variance (ANOVA) and least absolute shrinkage and selection operator (LASSO) regression were used to select radiomic features, which were then constructed using three classification models, namely, logistic regression method (LR), support vector machine (SVM), and K-nearest neighbor (KNN). The diagnostic performance of the radiomics model was quantified by the receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) of the training and validation data sets.

RESULTS

The 20 most valuable features were investigated based on the LASSO regression. LR and SVM methods exhibited better diagnostic ability than KNN for multiclass classification. LR and SVM had the best performance and yielded the AUC values of 0.857 and 0.824, respectively, in the training data set and the AUC values of 0.932 and 0.912, respectively, in the validation data set of MSGT diagnosis.

CONCLUSION

DWI-based triple-classification radiomics model has predictive value in distinguishing PA, WT, and MSGT, which can be used for preoperative auxiliary diagnosis in clinical practice.

Is there a Role for Frozen Section Evaluation of Parotid Masses After Preoperative Cytology or Biopsy Diagnosis?

Fine-needle aspiration (FNA) biopsy reliably diagnoses parotid gland lesions preoperatively, whereas intraoperative frozen section (FS) has the additional benefit of assessing surgical margins and refining diagnoses; however, the role of FS in the setting of prior FNA diagnosis is not well established. Our aim was to determine whether FS should still be performed after a prior FNA/ CNB diagnosis. Parotid gland resections from January 2009 to January 2020 were identified; however, only patients who had both FNA and FS constituted our study population. For the purpose of statistical analysis, FNA diagnoses were classified into non-diagnostic (ND), non-neoplastic (NN), benign neoplasm (BN), indeterminate, and malignant. FS diagnoses were classified into benign, indeterminate, or malignant. Resections were dichotomized into benign and malignant and regarded as the gold standard to subsequently calculate diagnostic accuracy of FNA and FS. A total of 167 parotid gland resections were identified, but only 76 patients (45.5%) had both FNA and FS. In 35 cases deemed as benign preoperatively, three (8.6%) were reclassified as malignant on FS. Out of 18 lesions reported as malignant on FNA, four (22.2%) were interpreted as benign on FS, with three of these benign lesions confirmed on permanent slides. In addition, in patients with both FNA and FS, compared to FNA, FS was able to provide a definitive diagnosis in all five ND cases and in 61.1% (11/18) of indeterminate tumors. Intraoperative assessment provided a relative increase of 33.3% in specificity and 38.5% in positive predictive value when compared to preoperative FNA. The addition of FS to FNA was helpful to further refine the diagnoses of parotid gland lesions, which may provide better guidance for surgical intervention.

Accuracy of fine-needle aspiration cytology in the diagnosis of salivary gland masses according to the Milan reporting system and to an in-house system

BACKGROUND

This study aims to assess in our institutional experience the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of salivary gland masses (SGM) according to the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and to an in-house system.

METHODS

The study included 189 FNACs conducted between January 2011 and December 2019. The FNACs, classified according to the in-house system, were reclassified according the MSRSGC. Taking histopathology as gold standard, the measures of diagnostic accuracy of FNAC were determined for suspicion for malignancy (SFM) and malignant categories.

RESULTS

According to the in house system, FNAC diagnoses were classified as: 23 (12.2%) non-diagnostic (ND), 23 (12.2%) non-neoplastic (NN), 119 (62.9%) benign neoplasm (BN), 10 (5.2%) indefinite neoplasm (IN), 2 (1.1%) SFM, and 12 (6.4%) malignant (M). Based on the MSRSGC, there were 3 (1.5%) cases of atypia of undetermined significance (AUS) and 7 (3.7%) neoplasms of uncertain malignant potential (SUMP). The number of ND, NN, BN, SFM, and M cases were identical in the two systems. For both systems, the sensitivity, the specificity, the positive predictive value, the negative predictive value, and the accuracy for malignancy diagnosis were 77.8%, 100%, 100%, 97.6%, and 97.8%, respectively.

CONCLUSION

According to the MSRGC and to our in-house reporting system, FNAC is an accurate technique for the diagnosis of malignant salivary tumors with excellent specificity and good sensitivity. However, MSRGC has the advantage of standardization of salivary gland cytology reporting.

A novel clinically-oriented classification of fine-needle aspiration cytology for salivary gland tumors: a 20-year retrospective analysis of 1175 patients

Background

When determining treatment strategy for a salivary gland tumor, assessing histology and malignancy grade before surgery is essential. Several new diagnostic classification systems for salivary gland cytology have recently been proposed. However, none incorporate histology and grade of malignancy.

Methods

We developed a new cytology classification system that incorporates histology and grade of malignancy of salivary gland tumors (OMC classification), consisting of 11 categories. Our OMC classification was applied to 1175 patients who had preoperative cytology and confirmed final pathological diagnosis available from the past 20 years at our hospital (benign tumor: 981 patients, malignant tumor: 194 patients).

Results

Based on the cytology, 729 patients (62.0%) had benign histology (Category 4–1), and 87 patients (7.4%) were diagnosed with grade of malignancy (Category 6–3 + 6–4). Based on the final pathological diagnosis, the accuracy rate of Category 4–1 and Category 6–3 + 6–4 of our classification system was 93.4% and 88.5%, respectively.

Conclusion

Based on the correct diagnosis rate, the inclusion of histology and grade of malignancy in the salivary gland cytology classification was considered feasible. Thus, the OMC classification system is considered a useful tool when determining the treatment strategy for a salivary gland tumor.

Putting morphology to the test: An established classification scheme reliably stratifies salivary gland cytology by risk of malignancy with substantial interobserver agreement

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology describes several salivary gland fine-needle aspiration cytology (SGFNAC) morphologies developed by Griffith et al. Basaloid neoplasms are pleomorphic (PB) or monomorphic with fibrillary (MBFib), hyaline (MBHy), or other (MBOther) matrix. Oncocytoid neoplasms can be pleomorphic (PO), demonstrate granular and/or vacuolated cytoplasm (OGV), or be monomorphic with mucinous (MOMuc), cystic (MOCyst), or other (MOOther) background. In the current study, the authors explore interobserver agreement (IOA) and risk of malignancy (ROM) for these subcategories.

METHODS

The study included 169 SGFNAC cases with surgical follow-up. Four reviewers categorized these cases using the criteria of Griffith et al. with consensus determined by majority. For all morphologic categories, IOA (using the Fleiss kappa) and ROM were calculated.

RESULTS

ROMs for basaloid categories were: PB: 100% (1 of 1 case); MBHy: 71.4% (5 of 7 cases); MBFib: 50.0% (3 of 6 cases); and MBOther: 47.4% (9 of 19 cases). ROMs for oncocytoid neoplasms were: OGV: 100% (10 of 10 cases); MOMuc: 92.3% (12 of 13 cases); PO: 88.9% (8 of 9 cases); MOOther: 33.3% (5 of 15 cases); and MOCyst: 0 (0 of 1 case). The system demonstrated substantial agreement overall (κ = 0.69). For basaloid neoplasms, the IOA results were: MBHy: κ = 0.59; MBFib: κ = 0.41; MBOther: κ = 0.41; and PB: κ = 0.11. For oncocytoid neoplasms, the IOA results were: MOMuc: κ = 0.88; OGV: κ = 0.67; PO: κ = 0.63; MOOther: κ = 0.57; and MOCyst: κ = 0.18.

CONCLUSIONS

The SGFNAC scheme proposed by Griffith et al. and incorporated into the Milan System for Reporting Salivary Gland Cytopathology demonstrated substantial agreement overall, with particularly high agreement for the MOMuc, OGV, PO, and MBHy categories. The PB and MOCyst categories demonstrated slight agreement and may be improved by revised criteria. The PB, PO, MOMuc, and OGV categories demonstrated high ROM, and the latter 2 categories might best be classified as suspicious for malignancy.

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.

Retrospective implementation of the Milan system for reporting salivary gland cytopathology; a review of 5 years in a specialized cancer center

BACKGROUND

The Milan system for reporting salivary gland cytopathology (MSRSGC) aims to standardize terminology, facilitate communication, and optimize management by providing risk of malignancy (ROM) for each category. Our retrospective cohort aims to study the reproducibility of reporting using the MSRSGC and to calculate the ROM for each category.

METHODS

Cases of fine needle aspiration (FNA) of salivary glands and related cervical lymph nodes were retrieved from our files between 2015 to 2019. From a total of 63 cytology cases, 57 cases had available material for cytological reexamination of which 45 cases had follow up data. All cases were reviewed independently by two pathologists and reclassified based on the MSRSGC. The reclassification of cases for both pathologists was compared and the ROM for each diagnostic category was calculated.

RESULTS

The 57 cases were studied. Both pathologists had initial concordance in classification of 52 of 57 cases. The remainder five cases were concurred upon after combined review. The cases were classified as: Non Diagnostic (ND); (n = 8), Non Neoplastic (NN); (n = 7), Atypia of Undetermined Significance (AUS); (n = 8), Neoplasm Benign (NB) (n = 10), Salivary Gland Neoplasm of Uncertain Malignant Potential (SUMP) (n = 5), Suspicious for Malignancy (SM) (n = 1) and Malignant (M) (n = 18). The ROM was: ND: (33.3%); NN: (0%); AUS (33.3%); NB (0%); SUMP (25%); SM (100%) and M (100%).

CONCLUSION

Applying the MSRSGC is reproducible which facilitates standardization of reports and stratifying cases preoperatively. In general, the ROM for our cases was close to that reported in the literature.

Application of Milan system for reporting of salivary gland pathology and risk stratification: An institutional experience

Background:

Fine-needle aspiration cytology (FNAC) is a sensitive technique for diagnosing salivary gland pathologies. Milan system of reporting salivary gland cytopathology (MSRSGC) is an evidence-based system of reporting which has been introduced to improve reporting and communication between cytopathologist and clinician by introducing standardized categories with specified treatment protocols.

Aims and Objectives:

The aim of the present study is to find the diagnostic accuracy and risk of malignancy (ROM) in various categories when MSRSGC is applied.

Materials and Methods:

A single-institute-based 3-year retrospective study was done. All salivary gland lesions were reclassified according to MSRSGC. ROM, diagnostic specificity, sensitivity and accuracy of FNAC of salivary gland lesions were calculated.

Results:

A total of 133 cases were included in the study. Overall, the most common diagnosis was found to be pleomorphic adenoma comprising 61 (42.8%) of all cases. Adenoid cystic carcinoma was the most commonly diagnosed malignancy comprising of 6 (4.5%) of all lesions. Cases were further divided into Milan categories, namely nondiagnostic, nonneoplastic, atypia of undetermined significance, benign neoplasm, neoplasm of undetermined malignant potential, suspicious of malignancy and malignancy comprising 5 (3.7%), 29 (21.8%), 77 (57.8%), 4 (3%), 3 (2.2%), 1 (0.7%) and 14 (10.5%) cases, respectively, with ROM of 0, 14.28%, 33.33%, 5.71%, 66.66%, 100% and 80%, respectively. Sensitivity, specificity and diagnostic accuracy to separate benign from malignant lesions were 80%, 89.80% and 87.50%, respectively.

Conclusion:

FNAC of the salivary gland lesions is a safe and reliable diagnostic procedure. The Milan system of reporting is a risk stratification system which can improve the overall effectiveness of reporting and care of patients.

Evaluation of NR4A3 immunohistochemistry (IHC) and fluorescence in situ hybridization and comparison with DOG1 IHC for FNA diagnosis of acinic cell carcinoma

BACKGROUND

Acinic cell carcinoma (AcCC) is diagnostically challenging on fine-needle aspiration because it can mimic several other neoplasms or even normal acinar tissue. Immunopositivity for DOG1, especially circumferential membranous staining, can support the diagnosis of AcCC but is not entirely specific, and it is prone to technical and interpretive challenges on small specimens. NR4A3 (nuclear receptor subfamily 4 group A member 3) translocation and nuclear NR4A3 overexpression were recently described in the majority of AcCCs. Here, the authors evaluate the performance of NR4A3 immunohistochemistry (IHC) and NR4A3 break-apart fluorescence in situ hybridization (FISH) on cell block preparations and compare them with DOG1 IHC in distinguishing AcCC from other entities in the differential diagnosis.

METHODS

The authors identified 34 cytology cell blocks with lesional cells, including 11 specimens of AcCC (2 of which derived from 1 patient and showed high-grade transformation) as well as 2 secretory carcinomas, 7 salivary duct carcinomas, 4 mucoepidermoid carcinomas, 3 oncocytomas, 3 renal cell carcinomas, and 6 specimens containing nonneoplastic salivary gland tissue. NR4A3 IHC, DOG1 IHC, and NR4A3 FISH were attempted for all cases.

RESULTS

NR4A3 IHC had 81.8% sensitivity and 100% specificity for AcCC, whereas NR4A3 FISH had 36.4% sensitivity and 100% specificity, although 4 cases (3 mucoepidermoid carcinomas and 1 salivary gland tissue sample) could not be analyzed because of low cellularity. Notably, no normal acinar tissue specimens showed NR4A3 positivity by IHC or FISH. In addition, DOG1 IHC had 72.7% sensitivity and 92% specificity.

CONCLUSIONS

NR4A3 IHC is highly specific for the diagnosis of AcCC and is more sensitive than DOG1 IHC and NR4A3 FISH. In addition, NR4A3 IHC performance is not improved by the inclusion of DOG1 IHC. Finally, NR4A3 positivity resolves the perennial problem of distinguishing AcCC from normal acinar tissue.

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.

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.

Controversies in the Workup and Surgical Management of Parotid Neoplasms

OBJECTIVE

Parotid neoplasms are a rare heterogeneous group of tumors with varied clinical presentation and behavior. Here we provide an evidence-based review of the contemporary approach to evaluation and surgical management of parotid tumors.

DATA SOURCE

PubMed and Web of Science Databases.

REVIEW METHODS

Searches of the PubMed and Web of Science databases were performed on subjects related to the diagnosis and surgical management of parotid neoplasms. Particular emphasis was placed on the following areas: evaluation of parotid tumors, including imaging workup and the utility of fine-needle aspiration; extent of surgery of the primary lesion, including the extent of parotidectomy as well as oncologic management of the facial nerve; the extent of surgery of involved and at-risk cervical lymphatics; and parotid bed reconstruction. Articles published from 2014 to the present were prioritized, supplementing with information from prior studies in areas where data are lacking.

CONCLUSION

A summary of the literature in these areas is outlined to provide an evidence-based approach to evaluation and management of parotid neoplasms.

IMPLICATIONS FOR PRACTICE

While data are available to help guide many aspects of workup and management of parotid neoplasms, further research is needed to refine protocols for this heterogeneous group of diseases.

Prediction of Malignancy in Salivary Gland Tumors by a New Cytology Reporting System

OBJECTIVES

The aim of this study was to analyze the risk of malignancy in salivary gland tumors on the basis of the Milan System for Reporting Salivary Gland Cytopathology.

METHODS

A retrospective review was performed of the charts of patients with salivary gland tumors in whom the final diagnosis was confirmed by surgical excision. Preoperative fine needle aspiration results were categorized according to the Milan System for Reporting Salivary Gland Cytopathology: non-diagnostic (category I), nonneoplastic (category II), atypia of undetermined significance (category III), neoplasm (category IV), suspicious for malignancy (category V), and malignant (category VI). Fine needle aspiration and final diagnosis were compared, and the risk of malignancy and operative/oncological outcomes were analyzed.

RESULTS

A total of 288 patients were enrolled in this study. Postoperative histopathologic salivary gland malignancies were found in 30 (10.4%) patients. Risk of malignancy was 7.1%, 0%, 48.0%, 4.8%, 88.7%, and 100% in categories I, II, III, IV, V, and VI, respectively. The most common malignant tumor in category III was salivary duct carcinoma (37.5%), followed by acinic cell carcinoma (25.0%), mucoepidermoid carcinoma (25.0%), and squamous cell carcinoma (12.5%). The 5-year survival rate of patients with malignant tumors showed no statistical difference between category III and category V/VI (P = .140). Risk of malignancy was 88.9% and 100% in category V and VI, respectively.

CONCLUSIONS

A half of atypia of undetermined significance (category III) cases were malignant. Once diagnosed, the prognosis of malignant tumor in category III was similar with that in category V/VI.