Salivary Gland Fine Needle Aspiration Research Articles

The indeterminate categories of the Milan system for reporting salivary gland cytopathology (MRSGC): A minireview

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC), first published in 2018, attempted to develop a standardized and objective system of reporting salivary gland fine needle aspiration smears. It was widely accepted by the cytopathologists who started using it in their day-to-day practice. With the publication of new literature, the Milan system was updated and the 2 edition was released in 2023. The 5 WHO classification of salivary neoplasms, ancillary tests, and imaging characteristics of various salivary neoplasms have also been highlighted in the new edition. The 3 indeterminate categories of the Milan system of reporting are the atypia of undetermined significance (AUS), salivary gland tumor of undetermined malignant potential (SUMP), and suspicious for malignancy (SM) that create major dilemmas for the reporting cytopathologists. The present minireview highlights the criteria of diagnosis and further workup of the various lesions in these categories.

Interobserver Reliability of Milan and Modified Milan System for Reporting Salivary Gland Cytopathology: An Institutional Experience.

In 2018, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was published, defining a diagnostic categorization scheme. However, this system of classification was criticized due to its suboptimal diagnostic accuracy and low interobserver reliability. For these reasons, the modified Milan system was recently proposed by a few authors claiming it to be more clinically reliable. The present study aimed to analyze the interobserver reliability of MSRSGC and modified MSRSGC. A total of 100 salivary gland fine-needle aspirations were reviewed over a 1-year period and classified by two independent observers according to MSRSGC and modified MSRSGC. Interobserver reproducibility was estimated using observed agreement and chance-corrected agreement (Cohen's kappa). An overall chance corrected agreement of 0.37 (fair) was obtained for the original Milan system and 0.41 (moderate) for the modified one. In addition, subcategories of modified MSRSGC performed better than the MSRSGC in terms of interobserver reliability. The present study suggests that modified MSRSGC should be accepted worldwide as the clinical relevance of any categorization scheme requires diagnostic accuracy along with excellent interobserver reproducibility.

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

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. 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. 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. 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.

Diagnostic Utility of the Milan System for Reporting Salivary Gland Cytology in a Tertiary Hospital of Western Nepal

Introduction: Salivary gland Fine Needle Aspiration Cytology is a well-established pre-operative diagnostic tool done routinely worldwide. Heterogeneity of salivary gland lesions makes Aspiration cytology diagnosis challenging for most cytopathologists. Milan system for reporting salivary gland cytology is a six tier reporting system developed to minimize inter-observer variability, thus to enhance reproducibility of cyto-diagnosis.
 Aims: To study diagnostic utility of Milan System for Reporting Salivary Gland Cytology.
 Methods: This is a one-year hospital based study done at Department of Pathology, Nepalgunj Medical College Teaching Hospital. It included 46 cases of salivary gland Cytology. Biopsy was available for 22 of them. Fine Needle Aspiration Cytology cases were reported as per the Milan System and subsequently correlated with gold standard histopathology.
 Results: Age of patients ranged from 8-79 years with submandibular and parotid gland being the commonly involved ones. Most cases were in Category II (Non Neoplastic) according to Milan System for Reporting Salivary Gland Cytology (48%) followed by Category IVa (Neoplasm- Benign) accounting for 37%. Pleomorphic Adenoma was the commonest Benign Neoplasm. Malignancy (Category VI) accounted for 11% of FNAC while suspicious for Malignancy (Category V) were 6% case. Diagnostic accuracy of the Milan System was calculated as 88.88%. Cohen Kappa test value 0.81 showed strong agreement between cytology reporting by Milan System and biopsy.
 Conclusion: The Milan System for Reporting Salivary Gland Cytology should be applied for standardization of salivary gland cytology reporting as there is a good correlation between it and Histopathology, hence are complementary to each other.

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

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. 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. Literature review and personal institutional experience. 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.

Correlation of Fine Needle Aspiration Cytology and Histopathological Evaluation in Salivary Gland Masses: A Single Center Retrospective Study

Aim: Fine-needle aspiration cytology (FNAC) in the preoperative diagnosis of salivary gland (SG) masses is a very fast, inexpensive, and reliable diagnostic method. In our study, the correlation of cytological-histopathological diagnosis in cases diagnosed with fine needle aspiration cytology in our clinic was investigated, and possible causes of diagnostic entrapment in discordant cases were discussed. Material and Methods: Salivary gland FNAC cases with histopathological diagnosis between 2008 and 2019 were retrospectively analyzed.The age, gender, localization of the lesion, preoperative cytology, and postoperative histopathological diagnosis of the patients were recorded. Cytology results were analyzed in 5 categories: unsatisfactory, uncategorized, benign, suspected malignancy, and malignant. Histopathology results were recorded in 2 groups benign-nonneoplastic and malignant. Statistically significant difference level was accepted as p<0.05. The validity of the cytology result according to the biopsy result was evaluated by sensitivity, specificity, positive predictive value, and negative predictive value. Results: 316 cases of salivary gland fine needle aspiration were detected. 156 (49.4%) of 316 cases had histopathological diagnosis. When calculating the cytological-histopathological diagnosis, the cases that were found to be inadequate and uncategorized by cytology were not taken into consideration. The suspected malignancy group was evaluated within the malignant category. Therefore, diagnostic agreement was calculated in 124 cases. Of these 124 cases, 116 (93.6%) cytology-histopathology diagnosis were compatible, and 8 (6.4%) were not. In our series, the overall sensitivity and specificity were 83.3% and 97.7%, respectively. The positive predictive value was 93.7% and the negative predictive value was 93.4%. The accuracy rate was calculated as 93.5%. Conclusion: In our study, high sensitivity and specificity values were determined by FNAC in accordance with the literature. It should be kept in mind that there may rarely be differences between preoperative cytological and histopathological diagnoses, possibly due to experience, method, and lesion-related limitations and pitfalls.

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

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. 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. 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. 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.

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). 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. 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). 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.

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

Fine needle aspiration cytology is often used for the initial diagnosis and management of patients with salivary gland tumors. Because of its global usage, a consensus classification schema was devised in 2018 to initiate universal reporting of salivary gland cytology specimens, termed the Milan system for reporting salivary gland cytopathology (MSRSGC) and composed of distinct diagnostic categories. Few retrospective studies have been undertaken to review the MSRSGC within institutions. We analyzed salivary gland fine needle aspirations during a 10-year span from 2011 to 2021, categorized each cytology case to fit the MSRSGC, and subsequently reviewed the corresponding surgical resections, if indicated, to determine the rate of malignancy (ROM) and rate of neoplasia. Our ROM was higher (&gt;10%) for the following MSRSGC categories: non-neoplastic, atypia of undetermined significance, and suspicious for malignancy. Also, our data correlated well with the following MSRSGC categories: nondiagnostic, neoplasm-benign, salivary gland neoplasm of uncertain malignant, and malignant. Although the data were indicative of the ROM for surgically resected salivary gland lesions, the ROM for non-neoplastic lesions could truly be lower given that most lesions in this category will not undergo surgical resection. Additionally, determination of the rate of neoplasia could a tool that could be used to further guide our clinical colleagues.

The Milan System for Reporting Salivary Gland Cytopathology: A 3-year Retrospective Analysis in Patan Hospital

Introduction: The characteristics of salivary gland lesions identified by fine-needle aspiration cytology are varied and may overlap, which makes diagnosis difficult for cytopathologists. To provide consistency in the reporting of salivary gland cytology and to enhance clinic-pathologic communication, the "Milan system for reporting salivary gland cytopathology" has been introduced, which offers guidelines for diagnosis and treatment based on various categories of malignancy risk. Material and Methods: In this retrospective study, Fine needle aspiration cytology was done for all salivary gland lesions for three years and were retrieved from the Department of pathology, Patan hospital. All the cases were recategorized according to the Milan system for reporting salivary gland cytology with histopathology follow-up wherever available. Consistency of the two different types of assessment techniques (Milan category and primary cytology diagnosis) were assessed and the k score was calculated Results: A total of 58 cases were included in the study of which histological follow-up was available in 27 cases. Out of 58 cases, maximum cases 32 (55.1%) were classified under IVA followed by 15.5% cases classified under II, 8.6% of cases under Category IVB), 6.8% under category Vand 5.1% cases under category VI. Kappa's score was 0.58 which represents a moderate agreement. Conclusions: Milan system for reporting salivary gland cytopathology is a recently proposed six-category scheme, which places salivary gland fine needle aspiration cytology into well-defined categories that limit the possibilities of false negative and false positive cases.

Determination of Rates of Malignancy on Archival Salivary Gland Fine-Needle Aspiration Biopsy after Application of the Milan System for Reporting Salivary Gland Cytopathology in the Philippine General Hospital: A 1-Year Retrospective Study

Background. The Milan System for Reporting Salivary Gland Cytopathology (MSRGC) aims to increase the overall effectiveness of salivary gland FNAB by defining six general diagnostic categories with corresponding Rates of Malignancies (ROM). This study aims to use this system to categorize salivary gland FNAB in the Philippine General Hospital and stratify ROM per category. Methodology. In this study a total of 326 cases have been collected and reviewed, of which 154 (47.2%) had either surgical or clinical follow-up. The cases were assigned a Milan category by 3 cytopathologists blinded from the original diagnoses and from each other’s readings. Results. The overall sensitivity, specificity, PPV, and NPV in detecting neoplasm is at 71.6%, 90.9%, 88.3%, and 76.9%, respectively. On the other hand, the sensitivity, specificity, PPV, and NPV in detecting malignancy is at 52%, 92.9%, 59.1%, and 90.7%, respectively. The computed ROM is as follows: Category I 7.89%, Category II 9.43%, Category III 20%, Category IVa 10.53%, Category IVb 60%, Category V 75%, and Category VI 100%. Conclusion. The overall diagnostic utility of salivary gland FNAB, as well as the computed ROM per diagnostic category are comparable to internationally published literature. This study also validates the MSRSGC as a valuable tool in stratifying ROM in salivary gland lesions.

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.

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. 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. 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. 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.

Application of the Milan System for Reporting Salivary Gland Cytopathology: A systematic review and meta-analysis.

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a standard, evidence-based classification system for salivary gland fine-needle aspiration (SG-FNA). Since it was published in 2018, many researchers across the world have applied this uniform reporting system to their cohorts. The authors comprehensively reviewed cohort studies conducted since publication of the MSRSGC and performed a meta-analysis. The risk of neoplasm and the risk of malignancy (ROM) were calculated for each diagnostic category, and their diagnostic efficacy was evaluated. Thirty-five studies were included in the meta-analysis. The total number of SG-FNAs was 10,706, and 7168 of those had histopathologic follow-up. The ROM for each category was: nondiagnostic, 11.4%; nonneoplastic, 10.9%; atypia of undetermined significance, 30.5%; neoplasm-benign, 2.8%; neoplasm-salivary gland neoplasm of uncertain malignant potential, 37.7%; suspicious for malignancy, 83.8%; and malignant, 97.7%. Low-level heterogeneity was observed in ROM estimation. The sensitivity, specificity, and diagnostic odds ratio for differentiating malignant and benign lesions were 88.0%, 98.5% and 520.3, respectively. The reporting of SG-FNA using the MSRSGC demonstrated high diagnostic accuracy. The ROM for each category was generally concordant with the recommendations, except for the suspicious for malignancy category, which was significantly higher than the reference value. The tiered, standardized classification system would benefit the clinical management of salivary gland lesions.

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

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. 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). 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). 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.

Nondiagnostic category of Milan System for Reporting Pediatric Salivary Gland Cytopathology: outcomes and root cause analysis.

Fine-needle aspiration (FNA) results classified as the nondiagnostic category of the Milan system for reporting salivary gland cytopathology (MSRSGC) may be infrequently encountered in children. Clinical management may be challenging due to lack of data regarding outcomes and underlying causes. We retrospectively analyzed 106 consecutive pediatric salivary gland FNAs (2000-2020; 45% performed under image guidance). The outcomes of patients with nondiagnostic results were analyzed. Clinical parameters, FNA procedural parameters, and histopathologic parameters were compared between diagnostic and nondiagnostic cases. A root cause analysis was performed using the fishbone diagram and the 5 Whys method. A total of 103 initial FNAs were identified. The nondiagnostic rates for initial and repeat biopsy were 16% (16/103) and 67% (2/3), respectively. Initial nondiagnostic FNAs were most frequently managed by clinical/radiologic follow-up only (56%, 9/16), followed by direct surgery (19%, 3/16) and repeat FNA (19%, 3/16). By histologic and clinical/radiologic follow-up, the risk of malignancy for nondiagnostic cases was zero. Palpation guidance (P < .05), inadequate sampling determined by rapid on-site evaluation (P < .01), and lesions with cystic, vascular, or diffuse nature (P < .05) were significantly associated with nondiagnostic results. By root cause analysis, proceduralist sampling error and lack of ultrasound guidance were the most common primary and secondary causes, respectively. Pediatric salivary gland lesions of the nondiagnostic MSRSGC category have minimal risk of malignancy and may be successfully managed by clinical/radiologic follow-up. The root causes for nondiagnostic results were often multifactorial and primarily related to proceduralist sampling, characteristics of the lesions, and lack of ultrasound guidance.

Application of the Milan System for Reporting Salivary Gland Cytopathology in pediatric patients: An international, multi-institutional study.

Pediatric salivary gland fine-needle aspiration (FNA) is uncommon with a higher frequency of inflammatory lesions and a small proportion of malignancies. This international, multi-institutional cohort evaluated the application of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and the risk of malignancy (ROM) for each diagnostic category. Pediatric (0- to 21-year-old) salivary gland FNA specimens from 22 international institutions of 7 countries, including the United States, England, Italy, Greece, Finland, Brazil, and France, were retrospectively assigned to an MSRSGC diagnostic category as follows: nondiagnostic, nonneoplastic, atypia of undetermined significance (AUS), benign neoplasm, salivary gland neoplasm of uncertain malignant potential (SUMP), suspicious for malignancy (SM), or malignant. Cytology-histology correlation was performed where available, and the ROM was calculated for each MSRSGC diagnostic category. The cohort of 477 aspirates was reclassified according to the MSRSGC as follows: nondiagnostic, 10.3%; nonneoplastic, 34.6%; AUS, 5.2%; benign neoplasm, 27.5%; SUMP, 7.5%; SM, 2.5%; and malignant, 12.4%. Histopathologic follow-up was available for 237 cases (49.7%). The ROMs were as follows: nondiagnostic, 5.9%; nonneoplastic, 9.1%; AUS, 35.7%; benign neoplasm, 3.3%; SUMP, 31.8%; SM, 100%; and malignant, 100%. Mucoepidermoid carcinoma was the most common malignancy (18 of 237; 7.6%), and it was followed by acinic cell carcinoma (16 of 237; 6.8%). Pleomorphic adenoma was the most common benign neoplasm (95 of 237; 40.1%). The MSRSGC can be reliably applied to pediatric salivary gland FNA. The ROM of each MSRSGC category in pediatric salivary gland FNA is relatively similar to the ROM of each category in adult salivary gland FNA, although the reported rates for the different MSRSGC categories are variable across institutions.

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.

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

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

BackgroundThe Milan System for Salivary Gland Cytopathology (MSRSGC) is a categorical system for salivary gland fine‐needle aspiration cytopathology (FNAC) developed to aid clinicians in the management of salivary gland lesions. This classification is widely studied and validated, especially in cohorts that consist of mostly parotid gland lesions. However, only sparse literature describes the use of this classification for submandibular gland lesions in particular.MethodsAll patients in the Netherlands that underwent a submandibular gland resection between January 1, 2006, and January 1, 2017, with a FNAC before resection were identified with the use of the Dutch Pathology Registry database (PALGA). All FNAC results were retrospectively classified according to the MSRSGC. The risk of malignancy was calculated for all the MSRSGC categories. The sensitivity and specificity of the MSRSGC classification were calculated for submandibular gland FNAC.ResultsA total of 837 patients who underwent 975 FNAC aspirates from the submandibular glands were included in the analysis. Risks of malignancy for each of the MSRSGC categories were 14.4% in nondiagnostic, 4.4% in nonneoplastic, 37.0% in atypia of unknown significance, 3.9% in benign neoplasms, 40.7% in salivary gland neoplasms of unknown malignant potential, 76.2% in suspected malignant, and 91.3% in malignant cytology results. The sensitivity for diagnosing malignant submandibular gland tumors was 71.6% and specificity was 98.4%.ConclusionsThe results of the present study validate the use of this classification for submandibular gland lesions. Risks of malignancy vary according to the anatomical subsites of the salivary gland lesions.Lay Summary The risks of malignancy of the various Milan System for Salivary Gland Cytopathology (MSRSGC) categories vary according to the anatomical subsite of the salivary gland lesion.The proposed management techniques of the MSRSGC are valid for use with submandibular gland lesions.

Clinician's commentary: Atypia in salivary gland fine needle aspiration.

Due to the heterogenicity and morphological overlap among the broad spectrum of benign and malignant salivary gland lesions, cytopathology result interpretations can be challenging and variable even among the most experienced head and neck pathologist. There was no standardization of cytopathology result reporting until the recently proposed "Milan system for reporting salivary gland cytopathology" (MSRSGC). MSRSGC may offer more clarity and help minimize ambiguity, but surgeons, as part of multidisciplinary teams, do not only rely on the tiered stratification and risk of malignancy assessment. With only the MSRSGC reported, there may be critical information missing from the overall diagnostic evaluation of salivary gland masses. Cytopathologist evaluation, description of findings, and expert interpretation of the fine-needle aspiration cytology along with differential diagnosis can be critical pieces of information, that is, utilized in management discussions with patients and their families. This information needs to be included in every cytopathology interpretation in addition to the MSRSGC classification. In clinical practice, decisions concerning salivary gland tumor management are not based on single examinations but incorporate information from multiple sources including patient histories, clinical symptoms and signs, physical examinations, imaging studies, and when available, cytopathology. Additional cytopathology information will likely help to improve the utility and predictive power of MSRSGC, similar to Bethesda Classification and the predictive importance of nuclear atypia in indeterminate thyroid biopsy material for thyroid neoplasms.

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

Rapid on-site evaluation (ROSE) is a fine needle aspiration (FNA) technique for ensuring sampling adequacy and triaging samples. The Milan system for reporting salivary gland cytopathology (MSRSGC) is a standardised reporting system which aims to improve risk stratification. There is scant literature on the diagnostic value and agreement of MSRSGC on ROSE with final cytological diagnosis in salivary gland FNAs. We aimed to assess the concordance of MSRSCG categorisation and diagnosis on ROSE with final cytological and histological diagnosis. This prospective study included consecutive salivary gland FNAs for which ROSE was performed over a six-month period. MSRSGC category and diagnosis on ROSE were compared with the final cytological diagnosis and MSRSGC category, and histopathological diagnosis, where available. Sixty salivary gland aspirates were included. The adequacy rate with ROSE was 100%. Using the MSRSGC classification during ROSE, 26 (43.2%) samples were categorised as benign neoplasm, 21 (35%) as malignant neoplasm, 9 (15%) as non-neoplastic, and one each (1.7%) belonged to the remaining four categories. MSRSGC categorisation on ROSE concurred with final the cytological diagnosis in 58/60 cases (96.7%). Discrepancies in MSRSGC categories on ROSE included one atypia of undetermined significance with final report as non-neoplastic, and one non-diagnostic as suspicious for malignancy. Good correlation of MSRSGC categories on ROSE with final histopathological diagnosis (88.9% concordance) was also noted. MSRSGC on ROSE shows good concordance with final cytology and histopathology diagnosis, indicating that categorisation according to MSRSGC has utility in ensuring that adequate material is obtained and triaged appropriately for the diagnosis of salivary gland aspirates.