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

Background

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.

Methods

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).

Results

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.

Conclusion

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.

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 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.

Importance of radio-histo-cytopathological correlation, A retrospective study of cyto-histological and radiological correlation of salivary gland lesions using Milan System for Reporting Salivary Gland Cytopathology

BACKGROUND

Fine-needle aspiration cytology (FNAC) for salivary gland tumors can be challenging to due to the diversity of lesions and cytomorphological convergence between the tumors. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was hence developed and introduced to provide enhanced communication in salivary gland cytopathology. To evaluate the diagnostic utility and validity of MSRSGC in combination with ancillary radiological investigations, we aim to find correlation between Milan system and the radiological impression comparing with final histopathological diagnosis.

AIMS AND OBJECTIVE

Correlate the Milan category with the radiological and final histopathological diagnosis of salivary gland lesions. Review the FNAC diagnosis of salivary gland lesions and identify cytomorphological predictors of malignancy. Correlate the FNAC and the radiological diagnosis with final diagnosis in histopathology.

MATERIAL AND METHODS

A five year retrospective study, comprising fifty four cases of salivary gland FNAC were included in the study.

RESULTS

Majority of the cases belong to Milan VI-Malignant followed by Milan IVa-Benign and rest of cases were among other categories. The sensitivity, specificity, positive predictive value, and negative predictive value of adjuvant radiological diagnosis in differentiating benign and malignant salivary gland lesions was found to be 80%, 62.5%, 72.7%, and 71.4%, respectively. We could observe that the concurrent radiological assessment along with Milan system of reporting in salivary gland FNAC especially under suspicious categories (Milan Category IVb as well as Milan Category V) is a useful and sensitive predictor of malignancy.

CONCLUSION

A correlation with any form of ancillary radiological assessment is a helpful adjuvant with Milan system to derive a relatable diagnosis in salivary gland neoplasm especially those in categories describing the suspicious entities.

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.

Utility of the Milan system for reporting salivary gland cytopathology: A retrospective 5 years study

BACKGROUND

Fine-needle aspiration cytology (FNAC) is an established technique for preoperative diagnosis of salivary gland lesions; however, lack of a uniform reporting system has been a handicap. The main aims of this study were to evaluate the utility of the - "The Milan System for Reporting Salivary Gland Cytopathology" (MSRSGC) and ascertain the risk of malignancy (ROM) for each category.

METHODS

All salivary gland FNACs over 5 years (January 2014-December 2018) were reviewed and assigned a diagnostic category from the MSRSGC. Clinical data were taken from Cytology records. Cytodiagnosis was correlated with histopathology wherever available and ROM was calculated.

RESULTS

A total of 120 salivary gland FNACs were studied. Age ranged between 5 and 85 years, male:female ratio was 2:1 and parotid was the commonest gland aspirated. Cases were reclassified as I non-diagnostic (2.5%), II non-neoplastic (15%), III atypia of uncertain significance-AUS (1.7%), IV A neoplasm benign (50%), IV B neoplasm of uncertain malignant potential (12.5%), V suspicious for malignancy (5%), and VI malignant (13.3%). Follow-up was available in 70 (58.3%) cases. The sensitivity, specificity, negative predictive value, and positive predictive value were 92.3%, 100%, 100%, and 98.27% respectively. ROM was non-neoplastic (0%), AUS (50%), neoplasm benign (0%), neoplasm of uncertain malignant potential (28.6%), suspicious for malignancy (100%), and malignant (100%).

CONCLUSION

Salivary gland FNAC is a reliable diagnostic tool and the "Milan system" will further increase FNA reliability, help risk stratification, and improve patient care.

The effect of antiretroviral therapy on fine-needle aspiration of salivary gland masses in HIV-infected patients

BACKGROUND

South Africa has a very high prevalence of HIV/AIDS. Salivary gland lesions are common in HIV-infected patients. The aim of this study was to determine the pathologic entities diagnosed on fine-needle aspiration (FNA) of salivary gland masses in an HIV-infected study population that now has free access to antiretroviral (ARV) therapy and how this differs from the pathologic entities before the advent of widespread ARV availability, and if the Milan system for reporting salivary gland cytopathology (MSRSGC) can be applied to HIV-infected patients.

METHODS

A retrospective review was performed on confirmed HIV-infected patients who underwent FNA of salivary gland masses over a two-year period.

RESULTS

A total of 360 patients underwent FNA of salivary gland masses within the designated time frame, 58.3% (210) females and 41.7% (150) males. Patient ages ranged from 7 months to 67 years with a mean age of 36.9 years. The parotid gland was the most biopsied salivary gland at 55.3% (199). The most common diagnosis made in patients on antiviral therapy was lymphoepithelial cyst while that in patients not on antiviral therapy was infectious (including abscess and mycobacterial infection). The most frequent neoplasms were non-Hodgkin lymphoma, pleomorphic adenoma and squamous-cell carcinoma.

CONCLUSION

Patients on ARV therapy had higher CD4 counts, fewer infectious lesions, and more reactive and benign salivary gland lesions. Patients not on treatment had significantly lower CD4 counts and were frequently diagnosed with infectious processes. The MSRSGC is well-suited for use in HIV-infected patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.