Rapid On-site Evaluation (ROSE) Cytology of Mucoepidermoid Carcinoma and its Diagnostic Pitfalls: a Case Report

Fine needle aspiration cytology (FNAC) is a basic tool used for the preoperative diagnosis of superficial parotid swellings. Mucoepidermoid carcinoma accounts for approx. 5-10% of all salivary gland tumors. However, due to its morphologic heterogenicity, this tumor poses diagnostic difficulties in its interpretation. This is a case of a 45-year-old male with a history of recurrent swelling in the left infra-auricular region. Cytology with rapid on-site evaluation revealed a triphasic population of basaloid cells, squamoid cells, and intermediate cells on a mucoid background and reported as low-grade mucoepidermoid carcinoma in recurrence. The presence of a triphasic cellular component (mucous, intermediate, and squamoid cells) may not be seen in all cases of mucoepidermoid carcinoma (MEC) for definitive diagnosis. Clinico-radiological correlation, rapid on-site evaluation (ROSE), and high index of suspicion related to cystic lesions are important for early diagnosis and prompt treatment.

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.

Don't SUMP it! Utility of PLAG1 immunocytochemistry in basaloid SUMP subcategory

BACKGROUND

Basaloid salivary gland neoplasm of uncertain malignant potential (B-SUMP) is an indeterminate diagnostic subcategory, with pleomorphic adenoma (PA) representing the most common benign neoplasm. Pleomorphic adenoma gene 1 (PLAG1) staining is frequently seen in PAs and could aid in distinguishing them from other basaloid neoplasms. The authors evaluated the utility of PLAG1 immunocytochemistry (ICC) in differentiating PAs from other basaloid neoplasms in smears and liquid-based cytology (LBC) specimens.

METHODS

In total, 45 B-SUMP cytology aspirates and corresponding surgical excision specimens were identified. PLAG1 immunostaining was performed in all aspirates and surgical excision specimens and was scored as positive (strong/diffuse), equivocal (focal/weak), or negative.

RESULTS

PLAG1 ICC was performed directly on 38 smears and seven LBC specimens. PLAG1 was positive in 29 of 45 cases (64%), whereas six of 45 (13%) were equivocal, and 10 of 45 (22%) were negative. PLAG1-positive aspirates included 26 (90%) PAs, two (7%) basal cell adenomas (BCAs), and one (3%) carcinoma ex-PA. PLAG1-equivocal aspirates included four (67%) PAs and two (33%) BCAs, whereas negative aspirates included five (50%) BCAs, four (40%) adenoid cystic carcinomas, and one (10%) metastatic adenosquamous carcinoma. The sensitivity, specificity, positive, and negative predictive values were 87%, 86%, 93%, and 75%, respectively. Diagnostic accuracy was 87%.

CONCLUSIONS

PLAG1 ICC is useful when positive (strong/diffuse) and can be reliably performed on smears and LBC specimens. PLAG1 was positive in most PAs and in a small subset of BCAs. Therefore, in the absence of atypical cytologic features, PLAG1-positive tumors could be diagnosed as benign, with a note favoring PA versus BCA. In contrast, PLAG1-negative/equivocal tumors should remain in the B-SUMP category.

Cytopathology of salivary gland myoepithelial carcinoma: A study of 13 cases and review of the literature

INTRODUCTION

Myoepithelial carcinoma (MECA) is an infrequently recognized salivary gland (SG) neoplasm that commonly develops within a preexisting pleomorphic adenoma (MECA ex PA). Fine-needle aspiration (FNA) biopsy reports of this neoplasm are largely restricted to small series and single case reports.

METHODS

Our cytopathology files were searched for examples of SG MECA/MECA ex PA having confirmatory histopathologic verification. Conventional FNA biopsy smears were performed, and exfoliative specimens processed using standard techniques.

RESULTS

Thirteen cases from 9 patients (M:F = 3.5:1; age range: 36 to 95 years, mean age = 60 years) met inclusion criteria. FNA biopsy sites included parotid gland (4), trunk (2), scalp (2), and neck (2). Exfoliative specimens included pleural fluid (1), bronchial brushing (1), and bronchoalveolar lavage (1). Most cases were metastatic deposits (8; 62%), 4 were primary neoplasms, and 1 a local recurrence. FNA diagnoses were MECA ex PA (6; 46%), myoepithelial neoplasm (2), PA (2), basaloid neoplasm (1), atypical myoepithelial cells (1), and myxoma (1). Ancillary testing in 2 cases showed positive staining for myoepithelial markers. Cytologic features were that of a low-grade neoplasm composed principally of epithelioid/polygonal cells exhibiting minimal if any cytologic atypia. Myxoid and chondromyxoid stroma was often the dominant feature in MECA ex PA aspirates.

CONCLUSION

In the primary setting, a cytologic diagnosis of MECA/MECA ex PA is extremely challenging if at all possible. Due to overwhelming amounts of stroma, the diagnosis may be challenging in some cases of metastatic MECA ex PA.

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

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

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.

Application of the Milan System for Reporting Salivary Gland Cytopathology: A Single Institutional Experience of 354 Cases with Cytologic-Histologic Correlation

BACKGROUND

Evaluation of salivary gland lesions is routinely done preoperatively by fine-needle aspiration cytology (FNAC). The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC), with diagnostic categories I-VI, has been recommended to standardize the reporting of salivary gland lesions by FNAC. We aimed to reclassify archival salivary gland FNAC samples using MSRSGC, correlate the samples with surgical resections, and calculate the risk of malignancy (ROM) for each category.

METHODS

A total of 354 salivary gland FNAC samples (2013-2018) were reviewed. All FNAC results were retrospectively classified according to the MSRSGC. All cases had surgical follow-up. Histology was used to calculate the ROM, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy.

RESULTS

The 354 aspirates were classified as: nondiagnostic (ND) 17.0% (60), non-neoplastic (NN) 1.4% (5), atypia of undetermined significance (AUS) 11.0% (39), benign neoplasm (BN) 49.4% (175), salivary gland neoplasms of unknown malignant potential (SUMP) 10.7% (38), suspicious for malignancy (SM) 3.4% (12), and malignant (M) 7.1% (25). The ROM was as follows: ND 22%, NN 20%, AUS 15%, BN 2%, SUMP 53%, SM 75%, and M 96%. The diagnostic accuracy for separating benign versus malignant neoplasms was 96%. Cytologic-histologic correlation yielded a false-negative rate of 2.7%, false-positive rate of 10.5%, PPV of 89%, NPV of 97%, sensitivity of 87%, and specificity of 98%.

CONCLUSION

MSRSGC helps standardize cytology reports, provides useful information for appropriate clinical management, and ensures the best care of patients with salivary gland lesions.

Salivary gland neoplasms with basaloid features in the era of the Milan system for reporting salivary gland cytology: Classification and interobserver agreement

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has been shown to have moderate to good reproducibility for categorization of salivary gland fine-needle aspiration (FNA) specimens. Less is known of its accuracy and interobserver reproducibility for categorization of the diagnostically difficult group of basaloid neoplasms.

METHODS

Forty-five salivary gland specimens with a basaloid morphology (pleomorphic and monomorphic adenomas and adenoid cystic carcinomas) were independently assigned by seven cytopathologists to one of the MSRSGC categories. Interobserver agreement was assessed for average agreement, chance expected agreement and by Cohen's κ and diagnostic accuracy. Correlation of the salivary gland neoplasm of unknown malignant potential (SUMP) category with histologic diagnosis and benign or malignant designation along with interobserver reproducibility were calculated.

RESULTS

Average observed agreement for assignment to the MSRSGC was 46% and Cohen's κ = 0.2%. The SUMP category did not correlate with tumor type or with the benign or malignant nature of the neoplasm. Diagnostic specificity and sensitivity were 92% and 100% for consensus diagnosis, but were 76% and 77% for individual diagnoses.

CONCLUSION

The interobserver agreement in categorizing basaloid neoplasms by the MSRSGC is poorer than for salivary gland lesions overall. This reflects the difficulty in diagnosing basaloid neoplasms. Nonetheless, diagnostic accuracy appears similar to that of salivary gland neoplasms as a whole.

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.

Cytomorphologic features of intraductal salivary gland carcinoma: A multi-institutional study of 13 FNA cases with histologic, molecular, and clinical correlations

BACKGROUND

Intraductal carcinoma of the salivary gland (IDC) is a rare cancer with potential actionable targets, including RET fusions. Histologic and molecular features of IDC were recently reported, but cytomorphologic data are limited. In the largest multi-institutional fine-needle aspiration (FNA) series, the authors describe the cytomorphologic features of 13 IDC cases with available clinical, radiologic, histopathologic, and molecular data.

METHODS

The cases included 13 FNAs for 9 low-grade (LG) IDCs and 4 high-grade (HG) IDCs with corresponding histopathology and available molecular, imaging, and clinical data. Smears and liquid-based preparations available for 12 FNAs were semiquantitatively scored for key cytomorphologic findings and correlated with the corresponding resection.

RESULTS

LG IDC FNAs showed a cellular, biphasic population of large, atypical ductal cells with mildly pleomorphic nuclei in a clean background and a minor population of small, uniform myoepithelial cells. In contrast, all HG IDC FNAs showed predominantly ductal cells with marked nuclear pleomorphism, coarse chromatin, and necrosis. With the Milan system, most LG and HG IDC FNAs were classified as either salivary gland neoplasms of uncertain malignant potential (54%) or malignant (31%). Immunohistochemistry showed ductal epithelial reactivity with mammaglobin, androgen receptor, and S100, whereas myoepithelial cells were positive for p63 and/or calponin. Among cases with next-generation sequencing, 4 LG IDCs showed NCOA4-RET gene fusions, whereas an HG IDC showed HRAS and PIK3CA mutations.

CONCLUSIONS

The cytomorphology of IDC overlaps with other benign and malignant salivary gland neoplasms. Immunohistochemistry limits the differential diagnosis, but definitive classification requires molecular analysis. A diagnosis of IDC has potential implications for patient management.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Diagnostic performance of Milan system for reporting salivary gland cytopathology: A prospective study

BACKGROUND

Fine-needle aspiration (FNA) is a well-established modality for diagnosing salivary gland pathologies. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) provides a standardized uniform framework leading to an evidence-based risk of malignancy (ROM). Based on the current literature, ROM in the 6-tier MSRSGC ranges from <5% for neoplasm-benign to >90% for the malignant category. Here, we report our institutional experience adopting MSRSGC.

METHODS

The cytopathology group at our institution implemented MSRSGC at the end of 2018. Through a query of our laboratory information system, we identified all salivary gland FNA cases from 27 November 2018 to 26 October 2020. The pertinent surgical pathology follow-up was also extracted. After manual curation, data was analyzed in Rv4.0.2.

RESULTS

Our cohort comprised of 315 patients undergoing 343 salivary gland FNA biopsies, predominantly on the parotid (90%), 162 with a surgical pathology follow-up. The risk of malignancy ranged from 3.2% in neoplasm-benign (IVA) to 100% in suspicious for malignancy (V) and malignant (VI) categories. ROM in the other categories was: 12.5% for non-diagnostic, 0 for non-neoplastic, 33.3% for atypia of undetermined significance, and 41.9% for salivary gland neoplasm of uncertain malignant potential (SUMP). Most SUMP cases had a basaloid or oncocytoid cytomorphology with similar ROM. In distinguishing benign and malignant salivary gland lesions, FNA had adequacy of 93.6%, a diagnostic yield of 62.2%, a sensitivity of 93.1% and a specificity of 100%.

CONCLUSIONS

MSRSGC was successfully adopted by our cytology group and clinicians, with overall diagnostic performance similar to previous studies.

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

BACKGROUND

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

AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

FNA diagnostics of secondary malignancies in the salivary gland: Bi-institutional experience of 36 cases

OBJECTIVE

Fine-needle aspiration (FNA) is a key diagnostic method in the evaluation of salivary gland lesions. Secondary tumors of salivary glands represent only 5% of all malignancies of major salivary glands. The goal of our study was to examine the cytological and clinical features of secondary tumors sampled by FNA.

MATERIALS AND METHODS

A series of 36 secondary tumors from the pathology departments of two university hospitals are presented. Clinical referrals to FNA, cytological features, immunohistochemical results, and histopathological diagnoses were reviewed in all cases.

RESULTS

The study population consisted of 36 cases (19 males and 17 females) with mean age 70.9 ± 13.0 years (range 41-96 years). The most common site of the metastasis was parotid gland (n = 26). The primary malignancy was known in 17 cases at the time of FNA diagnosis. The most common primary site was skin of head and neck area (11 cases) followed by lungs (n = 5) and tonsils (n = 5), kidney (n = 2) and breast (n = 2) and thyroid gland, gastrointestinal tract and soft tissue, 1 case of each. In 8 cases, the primary site remained unknown. The diagnostic or confirmatory immunocytochemistry was performed on cell blocks in 21 cases.

CONCLUSIONS

FNA is a reliable technique in the diagnosis of salivary gland secondary malignancies. The knowledge of the personal history of malignancy is essential for the successful immunocytochemical targeted diagnosis without any delay.

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.

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.

The Milan system for reporting salivary gland cytopathology: Single center experience with cell blocks

BACKGROUND

Salivary gland fine needle aspiration (FNA) has a well-established role in the evaluation of salivary gland lesions. The Milan system for reporting salivary gland cytopathology (MSRSGC) was developed in 2018 to accomplish a standardized reporting across institutions. This classification is predominantly based on the use of direct smears. This single center study aims to evaluate and further validate the MSRSGC based on the sole use of cell blocks and carry out a risk assessment based on follow up histopathology.

METHODS

A total of 359 FNA specimens from 343 patients processed as cell blocks between 2012 and 2018 were retrieved, with histologic follow-up available in 235 cases. The cytological diagnosis were reclassified according to the MSRSGC categories: non-diagnostic, non-neoplastic, atypia of undetermined significance (AUS), benign neoplasm, salivary gland neoplasm of uncertain malignant potential (SUMP), suspicious for malignancy (SFM), and malignant. The use of ancillary immunohistochemistry or molecular testing was recorded. The risk of malignancy (ROM) was calculated for each diagnostic category.

RESULTS

Overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 92.9%, 75.9%, 97.9%, 91.7%, and 95%, respectively. The ROM for the non-diagnostic, non-neoplastic, AUS benign neoplasms, SUMP, SFM and malignant categories were 13.8%, 14.2%, 30%, 6.3%, 20.8%, 60%, and 100%, respectively.

CONCLUSION

This large single center retrospective series further validates the MSRSGC. The proposed diagnostic classification is reproducible with use of cell blocks. Discrepancies in number of cases per category and ROM are based on cross-institution variabilities, pre-FNA diagnostics (imaging) and ancillary tests.

The role of the Milan system for reporting cytopathology

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cytologic grading of primary malignant salivary gland tumors: A blinded review by an international panel

BACKGROUND

Fine needle aspiration (FNA) is commonly used for the preoperative evaluation of salivary gland tumors. Tumor grade is a key factor influencing clinical management of salivary gland carcinomas (SGCs). To assess the ability to grade nonbasaloid SGCs in FNA specimens, an international panel of cytopathologists convened to review and score SGC cases.

METHODS

The study cohort included 61 cases of primary SGC from the pathology archives of 3 tertiary medical centers. Cases from 2005 to 2016 were selected, scanned, and digitized. Nineteen cytopathologists blinded to the histologic diagnosis reviewed the digitized cytology slides and graded them as low, high, or indeterminate. The panelists' results were then compared to the tumor grades based on histopathologic examination of the corresponding resection specimens.

RESULTS

All but 2 of the 19 (89.5%) expert panelists review more than 20 salivary gland FNAs per year; 16 (84.2%) of the panelists work at academic medical centers, and 13 (68.4%) have more than 10 years' experience. Participants had an overall accuracy of 89.4% in the grading of SGC cases, with 90.2% and 88.3% for low- and high-grade SGC, respectively. Acinic cell carcinoma and mucoepidermoid carcinoma had the highest degree of accuracy, while epithelial-myoepithelial carcinoma and salivary duct carcinoma had the lowest degree of accuracy. As expected, the intermediate-grade SGC cases showed the greatest variability (high-grade, 42.1%; low-grade, 37.5%, indeterminate, 20.4%).

CONCLUSION

This study confirms the high accuracy of cytomorphologic grading of primary SGC by FNA as low- or high-grade. However, caution should be exercised when a grade cannot be confidently assigned.

A retrospective comparison of salivary gland fine needle aspiration reporting with the Milan system for reporting salivary gland cytology

BACKGROUND

Fine needle aspiration (FNA) is a routine sampling method in the diagnostic work up of salivary gland lesions. Despite universal use, no standardised classification existed for the cytopathological reporting of such entities until recently. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) aims to standardise the reporting of these lesions, offering risk of malignancy rates and clinical management recommendations.

METHODS

We retrospectively applied MSRSGC to cases reported over a 5-year period. Salivary FNA specimens were reclassified according to the MSRSGC as (I) non-diagnostic, (II) non-neoplastic, (III) atypia of undetermined significance (AUS), (IV) benign neoplasm and salivary gland neoplasm of uncertain malignant potential, (V) suspicious for malignancy, and (VI) malignant. Cases with surgical resections were documented and risk of malignancy calculated for each group, where possible. We compared our outcomes with similar studies performed since publication of the Milan criteria.

RESULTS

In total, 192 specimens were reassigned as non-diagnostic (n = 30), non-neoplastic (n = 31), AUS (n = 1), benign neoplasm (n = 97) and salivary gland neoplasm of uncertain malignant potential (n = 4), suspicious for malignancy (n = 3), and malignant (n = 26). There were 73 surgical resections. Our calculated risk of malignancy was within the proposed MSRSGC rates for the non-diagnostic, benign neoplasm and malignant groups. One AUS case did not undergo surgery. Benign and malignant sensitivities and specificities for the original reporting categories were 88.24% and 95.72%, and 100% and 95.45% for the MSRSGC, respectively.

CONCLUSION

Salivary gland FNA has high diagnostic accuracy and the MSRSGC offers standardised reporting and assistance in the stratification of cases. This may improve communication between pathologists and clinicians with improved outcomes for patients.

Fine-Needle Aspiration Cytology of Salivary Gland Lesions: A Revised Classification Based on "Milan System"-4years Experience of Tertiary Care Cancer Center of South India

Background:

Fine-needle aspiration cytology plays role in preoperative diagnosis of any salivary gland mass lesions. Because of heterogeneity of salivary gland lesions and cytomorphology overlap, a uniform 6-tier Milan classification proposed which could be helpful in better communication of reports for patient's management.

Methods:

Study included 4 years (2011–2015) retrospective data retrieval from cytology department of our Institute, which is a tertiary care cancer center of South India. Histopathology correlation was done wherever possible.

Result:

Total 253 cases were studied. Histopathological follow-up was available in 115 cases. Cases were categorized as nondiagnostic (1.58%), nonneoplastic (13.43%), benign (30%), atypia (0.8%), and suspicious for malignancy and malignant cytology (51.8%). The risk for malignancy was high for suspicious for malignancy and malignant cytological categories ranged from 96–100%. The sensitivity, specificity, and accuracy for diagnosing malignancy varied from 86.76%, 93.75%, and 89%, respectively.

Conclusion:

Risk stratification approach in classifying salivary gland cytology aspirate as per Milan system provides a standardized reporting and better communication to clinician.

Moving toward a systematic approach for reporting salivary gland cytopathology: cytohistological correlation with the application of the Milan system for risk stratification at a tertiary care center

INTRODUCTION

Fine-needle aspiration cytology (FNAC) of salivary glands is a well-established technique that plays a critical role in the preoperative diagnosis of lesions. Despite its clinical utility, it remains one of the most challenging areas in cytopathology. This is because there is no consensus on how to report salivary gland cytopathology, which has resulted in inconsistent terminology and confusion in communication among cytopathologists and clinicians. A risk stratification of FNA diagnostic categories has been recently proposed to be useful in reporting.

MATERIALS AND METHODS

A retrospective study of FNAC of salivary gland lesions reported from 2014 to 2017 was performed. The performance of the cytology reporting system was evaluated with histological diagnosis serving as the gold standard. The aspirates were then categorized according to the Milan system. Furthermore, the risk of malignancy was calculated for all diagnostic categories.

RESULTS

A total of 899 salivary gland aspirates were evaluated: 2.2% were nondiagnostic, 55.8% indicated nonneoplastic lesions, and 40.4% indicated neoplastic lesions. Histopathology was available for 172 cases. FNA had a sensitivity of 72.3% and a specificity of 92.6% with an overall diagnostic accuracy of 91.4% for differentiating malignant from benign tumors.

CONCLUSION

A tiered classification scheme as proposed by the Milan system may prove helpful in effectively guiding clinical management of patients with salivary gland lesions. Our experience with this system helps to pave the way for the adoption of the Milan System for Reporting Salivary Gland Cytopathology.

Cytopathological features of secretory carcinoma of salivary glands and ancillary techniques in its diagnostics: impact of new Milan system for reporting salivary gland cytopathology

Secretory carcinoma (SC) of salivary glands is a newly described low-grade malignancy characterized by the presence of ETV6 rearrangement. Only a few cases and very small series with cytomorphology were reported so far. Six cases of fine-needle aspirations (FNAs) from afterward histologically, immunohistochemically and genetically confirmed SCs were retrieved from the archives of the authors. Ancillary immunocytochemistry (ICC) and translocation detection were performed on cell blocks (CBs). All aspirates were sufficiently cellular and cells were arranged in more or less cohesive groups with only mild nuclear polymorphism. The cytoplasm was eosinophilic, granulated and vacuolated, especially in CBs. Secretory material within the microcystic spaces was periodic acid-Schiff (PAS) positive. Triple positivity of immunomarkers S-100 protein, mammaglobin and vimentin was present. The proliferation index was low. Ancillary techniques suggested the possibility of SC in a few cytology cases; nevertheless, the final diagnosis was based on histomorphology, immunohistochemistry and genetics. The SC of salivary glands is detectable pre-operatively using ICC and genetics. The presence of the diagnostic ETV6 rearrangement increases the accuracy of FNA to the maximum. According to the Milan system, cases genetically not confirmed should be categorized as Suspicious for Malignancy or Salivary Gland Neoplasm of Uncertain Malignant Potential (SUMP), both requiring surgery.

A Call for Universal Acceptance of the Milan System for Reporting Salivary Gland Cytopathology

OBJECTIVES

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) established a standardized, tiered reporting system for salivary gland fine-needle aspiration (FNA) that has gained international acceptance among cytologists. Our goal was to review the key features of the MSRSGC to familiarize the surgical community with this system and its application to the FNA evaluation of salivary gland masses.

METHODS

A comprehensive review of the MSRSGC and its application in clinical practice.

RESULTS

The MSRSGC consists of six major diagnostic categories: 1) nondiagnostic, 2) non-neoplastic, 3) atypia of undetermined significance, 4) neoplasm (benign or salivary gland neoplasm of uncertain malignant potential), 5) suspicious for malignancy, and 6) malignant. Each diagnostic category is associated with an implied risk of malignancy with implications for clinical management.

CONCLUSIONS

The MSRSGC is similar to the system used for reporting thyroid FNA, which is familiar to most otolaryngologists and head and neck surgeons. As this reporting system continues to gain popularity among pathologists, widespread understanding by surgeons will be important to standardize communication and classification of salivary gland cytopathology to improve clinical care. Laryngoscope, 130:80-85, 2020.

A comparison study of the reporting systems for salivary gland fine needle aspirations: Are they really different?

BACKGROUND

Recently a new system for reporting salivary gland fine-needle aspiration (FNA) cytology was proposed, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC). Herein, we evaluated diagnostic accuracy of salivary gland FNA, comparing the system previously used in our hospital with the Milan system.

METHODS

Salivary gland specimens obtained between 2011 and 2017 were reclassified according to MSRSGC. Risk of malignancy for each diagnostic category was determined. Diagnostic yield of both classifications was evaluated.

RESULTS

The cases (n = 388) were classified according to the old system: nondiagnostic (n = 28), benign (n = 246), atypical (n = 36), neoplastic (n = 57), suspicious for malignancy (n = 7) and malignant (n = 14). The lesions were distributed according to the MSRSGC: nondiagnostic (n = 28), non-neoplastic (n = 89), atypia of undetermined significance (n = 39), benign neoplasm (n = 156), neoplasm of uncertain malignant potential (n = 55), suspicious for malignancy (n = 7) and malignant (n = 14). When considering only benign and malignant cases, both classifications showed the same sensitivity (62.5%), specificity (100%) and similar accuracy (95.8%). Comparison between the two systems showed no significant difference.

CONCLUSIONS

Salivary gland FNA has high diagnostic accuracy and assists clinical management independently of the reporting system used, however, in some cases, the use of Milan system could be beneficial, since it allows an enhanced category stratification.

The utility of the Milan System as a risk stratification tool for salivary gland fine needle aspiration cytology specimens

OBJECTIVE

To perform a retrospective investigation of our institutional experience with salivary gland fine needle aspirations (FNA) through the framework of The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and assess the risks of neoplasm and malignancy for each diagnostic category.

METHODS

All salivary gland FNAs performed from January 2009 to December 2016 were retrospectively categorised according to the MSRSGC. When available, pre-operative cytological results were correlated with subsequent histological follow-up.

RESULTS

In total, 893 FNAs were reviewed. The specimens were retrospectively classified as nondiagnostic (ND: 13.5%), non-neoplastic (NN: 16.1%), atypia of undetermined significance (AUS: 10.8%), benign neoplasm (BN: 34.9%), salivary gland neoplasm of uncertain malignant potential (SUMP: 8.2%), suspicious for malignancy (SM: 2.7%) and malignant (M: 13.8%). Histological follow-up was available for 429 cases (48%); the majority (68.1%) were benign. The risks of neoplasm and malignancy for each category were as follows: ND: 64.5%, 16.1%; NN: 42.9%, 17.9%; AUS: 79.6%, 30.6%; BN: 100%, 2.2%; SUMP: 100%, 46.6%; SM: 94.7%, 78.9%; and M: 100%, 98.5%.

CONCLUSIONS

The MSRSGC is a useful classification scheme for stratifying salivary gland lesions according to their associated risk of malignancy and guiding clinicians toward appropriate management. Diagnostic pitfalls are seen in a small proportion of cases and a multidisciplinary approach for assessing salivary gland pathology is essential in their evaluation.

A retrospective 3-year study of salivary gland FNAC with categorisation using the Milan reporting system

INTRODUCTION

To assess our practice using the recently developed standardised classification system designated The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and to ascertain the rates of malignancy for each category by means of a retrospective study.

METHODS

All salivary gland FNAC samples received between 1 January 2013 and 31 December 2015 were retrospectively assigned a diagnostic category code from the MSRSGC. Cytology results were correlated with subsequent histology (where available), and clinical and radiological follow up.

RESULTS

A total of 287 salivary gland FNA samples were received from 272 patients. The specimens were classified as non-diagnostic (21.3%), non-neoplastic (22%), atypia of undetermined significance (2.4%), neoplasm benign (36.9%), neoplasm of uncertain malignant potential (5.2%), suspicious for malignancy (1.7%) and malignant (10.5%; low grade 1.4% and high grade 9.1%). Histological and clinical/radiological follow up was available for 138 (48.1%) specimens, clinical/radiological follow up only for 145 (50.5%) and no follow up for the remaining four (1.4%) samples. The risk of malignancy for each category was non-diagnostic (8.5%), non-neoplastic (1.6%), atypia of undetermined significance (0%), neoplasm benign (1.9%), neoplasm of uncertain malignant potential (26.7%), suspicious for malignancy (100%) and malignant (100%).

CONCLUSIONS

The MSRSGC appears to be a useful tool to guide clinical management and provide an indication of possible risk of malignancy. We favour implementing use of these categories in our reporting practice with a future re-evaluation to assess maintenance of service quality as well as the clinical utility of this reporting system.

Diagnostic Approach to Fine Needle Aspirations of Cystic Lesions of the Salivary Gland

Fine needle aspiration (FNA) has diagnostic and therapeutic value in the management of salivary gland cysts. Rendering an accurate diagnosis from an aspirated salivary gland cyst is challenging because of the broad differential diagnosis, possibility of sampling error, frequent hypocellularity of specimens, morphologic heterogeneity, and overlapping cytomorphology of many cystic entities. To date, there have been no comprehensive review articles providing a practical diagnostic approach to FNA of cystic lesions of salivary glands. This article reviews the cytopathology of salivary gland cysts employing 2017 World Health Organization terminology, addresses the accuracy of FNA, and presents The Milan System approach for reporting in cystic salivary gland cases. The utility of separating FNA specimens from salivary gland cysts, based upon the presence of mucin and admixed lymphocytes in cyst fluid is demonstrated. A reliable approach to interpreting FNA specimens from patients with cystic salivary gland lesions is essential to accurately determine which of these patients may require subsequent surgery.

Three-year cytohistological correlation of salivary gland FNA cytology at a tertiary center with the application of the Milan system for risk stratification

BACKGROUND

Fine-needle aspiration (FNA) cytology of salivary glands is a well-established technique that plays a critical role in the preoperative diagnosis of lesions. A risk stratification of FNA diagnostic categories has been recently proposed to be useful in reporting. The aims of this study were to evaluate the diagnostic accuracy of salivary gland FNA and to apply the proposed Milan system for reporting salivary gland lesions.

METHODS

A retrospective audit of FNA specimens of salivary gland lesions reported from 2014 to 2016 was performed. A correlation with the follow-up histopathology, wherever it was available, was performed. The aspirates were then categorized according to the Milan system as follows: nondiagnostic, nonneoplastic, atypical, benign neoplasm, neoplasm of uncertain malignant potential (NUMP), suspicious for malignancy, or positive for malignancy. Furthermore, the risk of malignancy and the risk of high-grade malignancy were calculated for all diagnostic categories.

RESULTS

A total of 631 salivary gland aspirates were evaluated: 2.2% were nondiagnostic, 55.8% indicated nonneoplastic lesions, and 40.4% indicated neoplastic lesions. Histopathology was available for 94 cases (14.9%). FNA had a sensitivity of 79.4% and a specificity of 98.3% with an overall diagnostic accuracy of 91.4% for differentiating malignant tumors from benign tumors. The overall risk of malignancy was 17.4% for the nonneoplastic category, 100% for the atypical category, 7.3% for the benign neoplasm category, 50% for the NUMP category, and 96% for the positive-for-malignancy category.

CONCLUSIONS

Salivary gland FNA continues to have high diagnostic accuracy and is thus helpful for guiding management. Neoplasms with classic cytomorphology are easily diagnosed; however, in difficult cases showing overlapping features, the use of the Milan system could be beneficial. Cancer Cytopathol 2017;125:767-75. © 2017 American Cancer Society.