Application of the Milan System of reporting salivary gland cytopathology and assessing its use as a risk stratification tool

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was proposed by American Society of Cytopathology and International Academy of Cytology to standardize reporting system ensuring uniformity and better communication between clinicians and cytopathologists. 1. To categorize salivary lesions as per MSRSGC. 2. To establish diagnostic accuracy of MSRSGC and calculate risk of malignancy for each diagnostic category. An ambispective study was conducted over 5 years including 45 FNAC cases of salivary lesions. The cases were categorized according to Milan System, and diagnostic accuracy of MSRSGC was established. Risk of malignancy for each category was calculated. The patients' age ranged from 13 to 77 years with maximum swellings in parotid (53.3%) followed by submandibular (15.6%) and submental (2.2%). Histopathological follow-up was done in all cases. The number of cases in each category was as follows: category I: 03 (6.7%), category II: 06 (13.3%), category III: 4 (8.9%), category IVA: 25 (55.6%), category IVB: 04 (8.9%), category V: 02 (4.4%), and category VI: 01 (2.2%). The calculated ROM was as follows: category I: 0%, category II: 0%, category III: 0% category IVA: 8.0%, category IVB: 25%, category V: 50%, and category VI: 100%. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy with (without) indeterminate categories for malignancy were 88.9%(96.9), 66.7%(50.0), 94.1%(94.1), 50.0%(66.7), and 85.7%(91.9), respectively. MSRSGC is an effective and standardized reporting system for categorization and risk stratification of salivary swellings which helps in enhancing patient care.