Revision of aspiration cytology in salivary gland masses according to the milan system and cytology-histology correlation

ENTRANCE Fine needle aspiration cytology (FNAC) is a fast, effective, low-cost and widely accepted method for diagnosing salivary gland lesions and deciding whether to refer patients to surgery or follow-up. The Milan System was developed to standardize cytopathological diagnosis in this method, which has become increasingly important in distinguishing malignant and benign neoplasms. With the Milan System, which has become widely accepted around the world, the malignancy risk rate is determined in each diagnostic category, and the diagnostic categories provide a higher level of prediction to the clinician. In our study, we aimed to re-evaluate the cases in our archive that underwent salivary gland aspiration and surgical resection according to the Milan System and to analyze our cytology-histology concordance rates. MATERIAL-METHOD 170 cases in our archive, whose salivary glands were evaluated by FNAC and resected between 2005 and 2023, were included in the study. Aspiration smears and histological sections of these cases were evaluated within the scope of the study. The smears were re-evaluated according to the Milan System. The categorization of old cytological diagnoses was appropriately revised without changing the original diagnosis in order to make a comparison with the Milan System, and cytological diagnoses were compared according to both systems. Cytological diagnoses of both systems were also compared with histopathological diagnoses. Malignancy risk ratio (ROM) and neoplasia risk ratio (RON) were calculated in each diagnostic category. Our results were compared with literature data by calculating diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). CONCLUSION Distribution of our cases into archive cytological diagnostic categories; nondiagnostic (ND); 46 (27.1%), nonneoplastic (NN); 23 (13.5%), suspected atypia/atypia of undetermined significance (SA/AUS); 2 (1.2%), benign neoplasia (BN); 85 (50%), cellular benign neoplasia/salivary gland neoplasm of uncertain malignant potential (SBN/SUMP); 1 (0.6%), suspected malignancy (MS); 3 (1.8%) and malignant neoplasia (MN); It was determined as 10 (5.9%). According to the Milan System, the distribution of our cases is; ND; 30 (17.6%), NN; 12 (7.1%), AUS; 27 (15.9%), BN; 74 (43.5%), SUMP; 14 (8.2%), MS; 3 (1.8%) and MN; It was 10 (5.9%). RON values of archive cytological diagnostic categories; ND; 63%, NN; 47.8%, AUS; 50%, RH; 96.4%, SUMP; 100%, MS; 66.6% and MN; While it was 100%, ROM values were calculated as 17.4%, 17.4%, 50%, 10.6%, 100%, 66.6% and 100% in the same order. Our sensitivity, specificity, PPD, NPD and diagnostic accuracy rates were 92.5%, 87.2%, 96.5%, 75.5% and 91.4%, respectively. RON values of Milan System categories are; ND; 50%, NN; 8.3%, AUS; 77.8%, RH; 100%, SUMP; 92.8%, MS; 66.6% and MN; While it was 100%, ROM values were calculated as 13.3%, 8.3%, 33.3%, 5.4%, 35.7%, 66.6% and 100% in the same order. Our sensitivity, specificity, PPD, NPD and diagnostic accuracy rates were 99.3%, 81%, 94.4%, 97.1% and 95%, respectively. ARGUMENT In our series, when we revised the cytological evaluation of salivary gland mass lesions on the basis of the Milan System, we saw that our cytological diagnoses, especially ROM, RON, sensitivity, NPD and diagnostic accuracy rates, improved, and we determined that these values became within or close to the limits recommended in the literature. In conclusion, the use of the Milan System in the evaluation of salivary gland mass lesions by aspiration cytology provides a significant improvement in the correlation with histological diagnosis, terminology standardization and clinical prediction. Key words: Salivary gland, neoplasm, aspiration cytology, Milan System, histological correlation