# The Milan system for reporting salivary gland cytopathology and cyto-histological correlation with special emphasis on cystic lesions—4 years study in a tertiary care institute

## TL;DR

This study evaluates the Milan system for reporting salivary gland lesions, focusing on cystic cases and their malignancy risk over four years at a tertiary care center.

## Contribution

The study emphasizes the high malignancy risk in cystic salivary gland lesions under the Milan system and suggests improved diagnostic approaches.

## Key findings

- Cystic lesions had a high risk of malignancy across all Milan categories.
- Category VI had the highest malignancy rate at 90.9%.
- Repeat guided FNAC and rapid on-site evaluation are recommended for better accuracy.

## Abstract

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was proposed by the American Society of Cytopathology and the International Academy of Cytology to bring uniformity in the reporting and treatment protocol. Cystic component is a common finding in non-neoplastic, benign and malignant lesions of the salivary gland. Fine needle aspiration is challenging in these cases due to pre-analytic error resulting in a high probability of false negativity.

To classify salivary gland lesions according to MSRSGC with special emphasis on cystic lesions and histological correlation.

The study included 214 cases of salivary gland Fine needle aspiration cytology (FNACs) and classified according to MSRSGC with calculation of risk of malignancy (ROM) for each category.

The most common age group affected was in the fourth - fifth decade (27.57%) and the common site was parotid gland. The majority of the cases belonged to the Milan category IVA (40.65%) and the least number in categories III and V (4.2%). Histopathology follow up was available in 50% of cases with the maximum number of surgery in category VI (78.5%). The highest ROM was for category VI (90.9%) followed by category V (83.3%). Cystic lesions constituted 22.64%, of which histopathological follow up was available in 64.58% of cases with a high ROM for category III and V(100%).

The ROM for cystic lesions is quite high for all categories as compared to the proposed MSRSGC. We suggest that repeat guided FNAC with a rapid on-site evaluation or ancillary diagnostic techniques can increase the diagnostic accuracy, especially for category I, III and cystic lesions.