A two-year study on fine needle aspiration cytology of salivary gland lesions with cytohistologic correlation and application of the Milan system

Abstract

Introduction and Aim: Fine needle aspiration cytology is a well-established and minimally invasive technique in the diagnosis and management of lesions of salivary gland. Literature shows a sensitivity of salivary gland cytopathology varying from 57% to 100% and a specificity varying from 90% to 100%. The Milan system for reporting salivary gland cytopathology was put forth with the idea of bringing out uniformity in reporting. Our study objectives were to classify all the lesions of salivary glands using the Milan system and to calculate the risk of malignancy for each Milan category with histology as the gold standard.   Methods and Materials: This was a two-year observational, retrospective study wherein the cases were categorised using the Milan system on cytology. Cytohistologic correlation was done wherever histopathologic follow-up was available and the risk of malignancy for each category was calculated with histology as gold standard.   Results: During the study period, 87 FNACs of salivary gland lesions were done. Of these, 54 cases had histopathologic follow-up. The category wise distribution of cases was as follows: 20.7%, 13.8%, 2.3%, 43.7%, 9.2%, 3.4%, and 6.9% for Milan category 1, 2, 3, 4a, 4b, 5, and 6 respectively, and the risk of malignancy was 20%, 0, 0, 3.8%, 87%, 100%, and 100% respectively.   Conclusion: The Milan system for reporting salivary gland cytopathology is of great value in categorising lesions of salivary gland. This system helps cytopathologists and clinicians in better patient management as it guides in risk stratification and provides an idea of risk of malignancy.