Application of the Milan System for Reporting Salivary Gland Cytology: A Prospective Study.

Background & objective: The Milan system of classification of the salivary gland lesions came up with an aim to establish a universal reporting protocol. The aim of this study was to classify the fine-needle aspiration cytology (FNAC) cases of salivary gland according to the Milan system.

Methods: All the cases presenting with salivary gland lesion for FNAC were considered. The clinical data was recorded. Cytology findings were analyzed according to the Milan System. Histopathological correlation was made wherever available.

Results: A total of 100 cases of salivary gland lesions were collected and categorized according to the Milan system. They were correlated with histopathology in 45 cases. The patients' age varied from 2-85 years. Parotid gland was the most commonly affected. Category 1 (non-diagnostic) comprised of three cases. Category 2 (non-neoplastic) had 40 cases. In category 4a (benign) there were 43 cases, and the most common lesion was pleomorphic adenoma. Category 5 (suspicious of malignancy) comprised of 3 cases. Category 6 (malignant) comprised of 11 cases and the most common lesion was mucoepidermoid carcinoma. In category 2, the cytological findings of 5 cases were concordant with histopathology while, 2 were discordant. In category 4a (benign), 20 cases were concordant, and 3 cases were discordant (2 cases were mucoepidermoid carcinoma, 1 was adenoid cystic carcinoma on histology). The risks of malignancy in NN, AUS, benign, SOM, and malignant were 33.3, 2.5, 0, 7, 66.6, and 100%, respectively.

Conclusion: Milan system of reporting salivary gland cytopathology may have great potential of escalating clinical communication and may guide appropriate treatment.