Prediction of Malignancy in Salivary Gland Tumors by a New Cytology Reporting System

Abstract

Objectives: The aim of this study was to analyze the risk of malignancy in salivary gland tumors on the basis of the Milan System for Reporting Salivary Gland Cytopathology. Methods: A retrospective review was performed of the charts of patients with salivary gland tumors in whom the final diagnosis was confirmed by surgical excision. Preoperative fine needle aspiration results were categorized according to the Milan System for Reporting Salivary Gland Cytopathology: non-diagnostic (category I), nonneoplastic (category II), atypia of undetermined significance (category III), neoplasm (category IV), suspicious for malignancy (category V), and malignant (category VI). Fine needle aspiration and final diagnosis were compared, and the risk of malignancy and operative/oncological outcomes were analyzed. Results: A total of 288 patients were enrolled in this study. Postoperative histopathologic salivary gland malignancies were found in 30 (10.4%) patients. Risk of malignancy was 7.1%, 0%, 48.0%, 4.8%, 88.7%, and 100% in categories I, II, III, IV, V, and VI, respectively. The most common malignant tumor in category III was salivary duct carcinoma (37.5%), followed by acinic cell carcinoma (25.0%), mucoepidermoid carcinoma (25.0%), and squamous cell carcinoma (12.5%). The 5-year survival rate of patients with malignant tumors showed no statistical difference between category III and category V/VI ( P = .140). Risk of malignancy was 88.9% and 100% in category V and VI, respectively. Conclusions: A half of atypia of undetermined significance (category III) cases were malignant. Once diagnosed, the prognosis of malignant tumor in category III was similar with that in category V/VI.

Comparisons among the Ultrasonography Prediction Model, Real-Time and Shear Wave Elastography in the Evaluation of Major Salivary Gland Tumors

“…Another important issue is that the diagnosis of cytology depends on the experience of pathologists and has the inter-institutional variability. Although the risk of malignancy (ROM) of AUS (atypia of undetermined significance) in the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was only 20%, several studies showed that their ROM of AUS was higher than 20%, around 47–50% [ 15 , 16 , 17 ]. Before the proposal of Milan system, the ROM of cytological report with atypia was also around 53%-63% [ 18 , 19 ].…”

“…A score of 1 represents almost soft (almost green within the lesion), a score of 2 represents mostly soft (green more than blue), a score of 3 represents mostly stiff (blue more than green), and a score of 4 represents almost stiff (almost blue). Using FNA cytology, the cytological report of atypia [ 15 , 16 , 17 , 18 , 19 ], suspicious malignancy or malignancy was classified as suspicious malignancy.…”

Milan system for reporting salivary gland cytopathology: Adoption and outcomes in a community setting

“…The observed rate of malignancy in our dataset is similar to the proposed risk of malignancy by the MSRSGC. These categories have been validated by multiple retrospective reviews of cytopathology reports across the globe since the introduction of the MSRSGC in 2015 6–8 . Viswanathan et al in 2018 performed a retrospective analysis of 627 salivary gland FNAs applying the MSRSGC and found strong correlation between the proposed risk of malignancy and the actual rate of malignancy after sialoadenectomy 9 .…”

“…These categories have been validated by multiple retrospective reviews of cytopathology reports across the globe since the introduction of the MSRSGC in 2015. [6][7][8] Viswanathan et al in 2018 performed a retrospective analysis of 627 salivary gland FNAs applying the MSRSGC and found strong correlation between the proposed risk of malignancy and the actual rate of malignancy after sialoadenectomy. 9 Rivera Rolon et al reviewed 208 salivary gland FNAs in 2020 that confirmed these findings and suggested a diagnostic accuracy of 94.4% when distinguishing benign versus malignant pathology.…”

Cytohistological correlation and risk stratification of salivary gland lesions using the Milan System for Reporting Salivary Gland Cytopathology: A tertiary care centre experience

“…1 FNA is a minimally invasive, relatively welltolerated, and cost-effective procedure, and it is widely accepted for differentiating non-neoplastic lesions from neoplastic lesions, and benign from malignant neoplasms. 1 The sensitivity and specificity of FNA in SGNs vary from 83% to 92% and from 93% to 100%, respectively. 3 Also, FNA provides prognostic information and ancillary molecular testing samples.…”