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.
Keywords: cytology; milan system; review; salivary gland cytopathology; salivary gland neoplasm.
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