ABSTRACT Objective Fine‐needle aspiration cytology (FNAC) is a key diagnostic method for salivary gland lesions. The Milan System for Reporting Salivary Gland Cytology (MSRSGC), a six‐tiered classification system, standardises reporting and provides risk of malignancy (ROM) for each category. Although MSRSGC recommends ancillary tests such as immunocytochemistry (ICC), reports on their clinical application remain limited. This study aimed to investigate the utilisation rate of ancillary tests in MSRSGC classifications and assess their effectiveness, particularly with liquid‐based cytology. Methods Diagnostic records of salivary gland FNAC cases at Kurume University Hospital (January 2020 to December 2024) were reviewed, and those evaluated by MSRSGC were extracted. Utilisation rate of ancillary tests, FNAC sensitivity and specificity, and ROM were calculated in cases with histopathological follow‐up. Results Among 321 salivary gland FNAC cases, 131 had histopathological follow‐up. Ancillary tests were used in 22.1% of cases, most often in SUMP (IVB), Suspicious for Malignancy (V) and Malignant (VI). ICC yielded a definitive histological diagnosis in 37.9% and a suggestive diagnosis in 27.6%. ROM by MSRSGC category was: Non‐Diagnostic (I) 0%; Non‐Neoplastic (II) 12.5%; AUS (III) 35.7%; Benign Neoplasm (IVA) 0%; SUMP (IVB) 27.8%; Suspicious for Malignancy (V) 75.0%; and Malignant (VI) 100%. FNAC sensitivity and specificity were 97.3% and 98.2%, respectively. Conclusions Ancillary testing, particularly ICC, enhances the reliability of MSRSGC and contributes to improved diagnostic accuracy.
Kawahara et al. (Tue,) studied this question.