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

Root Cause Analysis and Risk of Malignancy of Non-Diagnostic Category per the Milan System for Reporting Salivary Gland Cytopathology

INTRODUCTION

We aim to perform a root cause analysis (RCA) of the non-diagnostic (ND) category of the Milan System for Reporting Salivary Gland Cytopathology.

METHODS

The salivary gland fine needle aspiration (FNA) samples with ND diagnosis and corresponding surgical resections from 2013 to 2023, in the age group of 18 years and above, were included in the cohort for RCA. The cytology and surgical resection slides of cases from this RCA cohort were reviewed. The demographic parameters, clinical features, radiologic characteristics, usage of rapid on-site evaluation (ROSE), corresponding surgical diagnosis, and repeat FNA were noted.

RESULTS

A total of 2292 FNAs were performed between 2013 and 2023, of which 354 cases were ND. RCA was performed on 57 (16%) ND FNA cases that had corresponding surgical resection. The causes were grouped as man, method, machine, and material related. The primary cause predominantly was man-related sampling errors in 36 (63%) cases. There were no interpretative errors by the pathologist. The second most common primary cause was material related, found in 21 (37%) cases, due to cystic, fibrotic, vascular, and small lesions. The most common secondary cause was method related, in which 41 (72%) cases had no image guidance. There were no machine-related causes. The risk of malignancy in the RCA cohort was 17%.

CONCLUSION

Majority causes of ND cytology were method-related due to lack of image guidance and ROSE. This proves that the FNA procedure under radiologic guidance with ROSE is an effective way to circumvent ND cytology of salivary gland FNAs.

Performance Characteristics of Incisional and Core Needle Biopsies for Diagnosis in Parotid Gland: Single-Institutional Experience and Assessment of the Value of a Milan System for Reporting Salivary Gland Cytopathology-Like Risk Stratification Model

CONTEXT.—

Unlike parotid fine-needle aspiration biopsy, standardized reporting for core needle biopsy (CNB) and incisional biopsy (IB) is not established.

OBJECTIVE.—

To examine the value of risk stratification by a Milan System for Reporting Salivary Gland Cytopathology (MSRSGC)-like classifier for parotid CNB/IB.

DESIGN.—

Five hundred ninety-two parotid biopsy records (CNB = 356, IB = 236) were retrieved (1994-2022) along with clinicopathologic data. Diagnoses were transformed to an MSRSGC-like classifier and compared with end points including risk of malignancy.

RESULTS.—

Over time, CNB was progressively more used compared with IB. Overall malignancy call rate was 223 of 592 (37.7%). Common specific diagnoses included Warthin tumor, lymphoma subtypes, and metastatic squamous cell carcinoma for CNB and IB, in addition to pleomorphic adenoma for CNB. Descriptive diagnoses were still frequent. Nondiagnostic rates were higher in CNB (26 of 356; 7.30%) than IB (5 of 236; 2.12%; P < .001). Tissue volumes significantly influenced CNB adequacy, with minimum and optimal volumes of 4.76 mm³ (J index, receiver operating characteristic curve) and 12.92 mm³ (95th percentile of distribution), respectively. One hundred forty-four patients (112 CNBs) had follow-up resections; diagnoses were concordant for 66 of 73 adequate CNBs (90.41%). Our restructured risk grouping of MSRSGC categories performed robustly in terms of risk of malignancy (sensitivity = 85.5%, specificity = 100%, accuracy = 92.3%, area under the curve = 0.9677).

CONCLUSIONS.—

Although CNB and IB are amenable to a risk stratification system, there are some differences as compared with fine-needle aspiration biopsy, particularly given the high baseline prevalence of malignancy. Specific diagnoses are often feasible and concordant with resection. CNB tissue volume can inform optimal and minimal sampling recommendations for adequacy.

Exploring the Landscape of Salivary Gland Disorders: A Comprehensive Bibliometric Analysis

Objective

This study aims to conduct a major bibliometric analysis of salivary gland disorders, exploring publication characteristics, trends, and influential contributors. The primary objective is to improve understanding of the current state of research in this area and to identify potential directions for future investigation.

Methods

A comprehensive study was conducted analysing 11,679 publications from 1980 to 2023 retrieved from the Web of Science Core Collection. The analysis included collaboration across countries, keyword co-occurrence, co-citation networks and clustering. CiteSpace and VOSviewer were used to explore relationships and create visualisations.

Results

The analysis revealed a dynamic landscape of salivary gland research, with the United States leading in both the number of publications (n = 2998) and centrality (0.26). Network analysis unveiled nine clusters, including topics such as parotidectomy and immunohistochemistry. Co-occurrence analysis of keywords highlighted evolving trends, with recent emphasis on terms such as sialendoscopy, cytopathology, and gene fusion. The timeline view illustrated the changing significance of terms over the years, reflecting current areas of interest such as radiomics and mucoepidermoid carcinoma.

Conclusion

This study provides a comprehensive overview of the field, offering insights into influential work, collaborative networks, and emerging trends. The outputs of the analysis can guide researchers and clinicians in shaping future investigations.

Interventional cytopathologist perspective on the Milan System Classification: a study on 929 consecutive salivary gland fine-needle aspirations with a focus on challenging diagnostic categories

Background

Although the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has improved the diagnosis and management of salivary gland lesions, determining the risk of malignancy (ROM) for AUS and SUMP categories remains challenging. We investigated the role of interventional cytopathologists in refining the differential diagnosis of these categories.

Methods

We searched for salivary gland fine-needle aspirations (FNAs) performed at our Institution since the publication of the first edition of MSRSGC. In our Institution, salivary gland FNAs are performed by interventional cytopathologists only. We checked for the availability of histopathology reports to calculate the risk of neoplasm (RON) and ROM. Sensitivity, specificity, negative predictive value, and positive predictive values of our FNAs were assessed by focusing on the contribution of the AUS and SUMP categories to our diagnostic accuracy.

Results

929 salivary gland FNA diagnoses were retrieved. 37.02% FNAs had an available surgical follow-up. The ROM for each category was: 6% (ND); 0 (NN); 15.15% (AUS); 1.14% (NB); 24.4% (SUMP); 66.7% (SFM); and 94.74% (M). We observed a high level of concordance between our ROM data and the values proposed by the MSRSGC; higher accuracy (93.17%) and sensitivity (97%) were obtained when the AUS category was considered as a positive index for detecting salivary neoplasms; the best diagnostic accuracy (93.33%) was obtained when the SUMP category was considered as a negative index for malignancy.

Conclusion

Interventional cytopathologists play an important role in salivary gland cytopathology, as demonstrated by the overt concordance between our ROM rates and those recommended by the MSRSGC.

Update on Salivary Gland Fine-Needle Aspiration and the Milan System for Reporting Salivary Gland Cytopathology

CONTEXT.—

Fine-needle aspiration (FNA) is a well-established procedure for the diagnosis and management of salivary gland lesions, despite challenges imposed by salivary gland tumor diversity, complexity, and cytomorphologic overlap. Until recently, the reporting of salivary gland FNA specimens was inconsistent among different institutions throughout the world, leading to diagnostic confusion among pathologists and clinicians. In 2015, an international group of pathologists initiated the development of an evidence-based tiered classification system for reporting salivary gland FNA specimens, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC). The MSRSGC consists of 6 diagnostic categories, which incorporate the morphologic heterogeneity and overlap among various nonneoplastic, benign, and malignant lesions of the salivary glands. In addition, each MSRSGC diagnostic category is associated with a risk of malignancy and management recommendations.

OBJECTIVE.—

To review the current status of salivary gland FNA, core needle biopsies, ancillary studies, and the beneficial role of the MSRSGC in providing a framework for reporting salivary gland lesions and guiding clinical management.

DATA SOURCES.—

Literature review and personal institutional experience.

CONCLUSIONS.—

The main goal of the MSRSGC is to improve communication between cytopathologists and treating clinicians, while also facilitating cytologic-histologic correlation, quality improvement, and research. Since its implementation, the MSRSGC has gained international acceptance as a tool to improve reporting standards and consistency in this complex diagnostic area, and it has been endorsed by the 2021 American Society of Clinical Oncology management guidelines for salivary gland cancer. The large amount of data from published studies using MSRSGC served as a basis for the recent update of the MSRSGC.

Utility of the Milan System for Reporting Salivary Gland Cytopathology in fine needle aspiration cytology of minor salivary gland lesions

INTRODUCTION

Salivary gland lesions are routinely evaluated by fine-needle aspiration cytology (FNAC) preoperatively. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has standardized salivary gland FNAC reporting. Its application in major salivary glands (MSGs) has been well-established; however, its utility in minor salivary glands (MiSGs) is not well-known. We studied the utility of MSRSGC in MiSG FNAC.

MATERIALS AND METHODS

A retrospective search of MiSG FNACs from 2 academic institutions (2006-2023) was performed. FNACs were classified using the MSRSGC. Histologic data were reviewed and recorded. The risk of malignancy (ROM), risk of neoplasia (RON), diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

The series included 43 MiSG FNAC (24 males and 18 females), with a mean age of 55 years (range 10-92). Aspirated sites included the following: palate, buccal space, floor of mouth, lip, tongue, and maxillary sinus. FNACs were classified as nondiagnostic (1), nonneoplastic (3), atypia of undetermined significance (6), benign neoplasm (9), salivary gland neoplasm of uncertain malignant potential (15), suspicious for malignancy, (2) and malignant (7). The risk of neoplasia and risk of malignancy were 87% and 39%. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 100%, respectively.

CONCLUSIONS

Milan System for Reporting Salivary Gland Cytopathology offers valuable information for stratifying MiSG lesions. However, the distribution and the range of diagnostic entities encountered differ somewhat from those in MSGs. For instance, mucinous cyst contents may warrant unique consideration in MiSG; while an atypical classification is recommended in MSGs, the high prevalence of mucoceles in MiSG may tilt this group toward benignity.

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.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

The Second Edition of the Milan System for Reporting Salivary Gland Cytopathology: System Application, Outcome, and Cytohistological Correlation

Background

Fine needle aspiration (FNA) cytology for salivary gland lesions is sensitive and specific for diagnosing and treating salivary gland pathologies. The objective of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is to organize the diagnostic information from the FNA into a uniform reporting terminology.

Aims

The study was conducted retrospectively to reclassify previous diagnoses into the MSRSGC categories to determine the cytohistological concordance and assess the risk stratification by calculating the risk of malignancy (ROM) for different categories.

Materials and Methods

A total of 248 FNA cases of salivary gland lesions were analyzed and reclassified according to the second edition of the MSRSGC. The histological diagnosis was considered the gold standard. The ROM for each category was calculated based on 101 histopathologic follow-up cases.

Results

Of the 248 patients, 1.2% were classified as nondiagnostic, 37.9% as nonneoplastic, 1.2% as atypia of undetermined significance (AUS), 52.8% as benign neoplasm, 0.4% as uncertain malignant potential (SUMP), 0.4% as suspicious of malignancy (SFM), and 6.1% as malignant neoplasm. Histopathological correlation was available in 101 cases. The ROM was 0% for nonneoplastic lesions and benign neoplasms, and 100% for AUS, SUMP, SFM, and malignant categories. The sensitivity, specificity, positive predictive value, and negative predictive value of FNA cytology in diagnosing salivary gland lesions using MSRSGC were found to be 76.5%, 100%, 100%, and 95.3%, respectively.

Conclusion

The use of the MSRSGC helps in triaging patients with salivary gland lesions, increases the effectiveness of communication between clinicians and pathologists, and thus facilitates individualized patient management.

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.

Does Milan affect management? A retrospective analysis of resection rate and time to surgery among Milan categories

INTRODUCTION

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is an established system with reproducible risk of malignancies (ROM) for salivary gland fine needle aspiration (SGFNA). No studies have reviewed the relationship between Milan categories and the resection rate (RR) and time to resection (TTR).

METHODS

We searched our database (January 1, 2011 to January 4, 2021) for non-lymphoma SGFNAs and assigned appropriate MSRSGC categories. RR and TTR were calculated and compared for each category. A literature search was performed; RRs and TTRs were compared.

RESULTS

Seven hundred and eighty SGFNAs were identified, 333 with follow-up. RR was highest in suspicious for malignancy (SUS, V; 70.6%, n = 12/17), followed by the salivary gland neoplasm of uncertain malignant potential (SUMP, IVb; 69.6%, n = 80/115) and malignant (M, VI; 55.6%, n = 75/135). Among M, primary tumors had a higher RR (65.1%, n = 41/63) than metastases (47.2%, n = 34/72, p = .36). In literature review, SUS had the highest RR (69.3%, n = 233/336) followed by M (61.6%, n = 821/1332) and SUMP (60.2%, n = 632/1050). TTR was shorter in SUS (mean = 32.3 days, median = 25 days). Within the benign neoplasms (BN, IVa), Pleomorphic adenomas (PAs) had a higher RR than Warthin tumors (WTs) (66.3% vs. 37.2%, p < .00001), and a shorter TTR (median = 63 days vs. 90 days).

CONCLUSIONS

Tumors classified as SUS had higher RR and at shorter intervals than those classified as SUMP. PAs have higher RRs and more expedient surgery than WTs. Cases classified as M are less likely to undergo follow-up than SUS, perhaps due to a lower RR for metastases.