Risk stratification of salivary gland cytology utilizing the Milan system of classification

Abstract

Background The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is based on risk stratification. Our study is a retrospective review of salivary gland fine needle aspiration cytology (FNAC) with the goal of determining the risk of malignancy (ROM) in each of the categories proposed by the MSRSGC. Methods FNAC of salivary gland lesions with corresponding surgical resection specimens were retrieved over a 5‐year period. Metastatic tumors were excluded. BothFNAC and corresponding surgical resections were reviewed blindly and classified as per criteria published by the MSRSGC. The ROM for each of the diagnostic categories was determined and compared with the ROM published by the MSRSGC. Results The total number of entities and ROM in 199 reviewed cases were as follows: Nondiagnostic 18 (9.2%) (ROM 0%), non‐neoplastic 4(2%) (ROM 0%), atypia of undetermined significance (AUS) 12(6%) (ROM 33%), benign neoplasm 118(59.2%) (ROM 0.8%), salivary gland neoplasm of uncertain malignant potential (SUMP) 22(11%) (ROM 40.9%), suspicious for malignancy 3(1.5%) (ROM 100%), malignant 22(11%) (ROM 100%). Conclusion The ROM reported in our study was mostly concordant with ROM published by the MSRSGC. This classification is helpful for the management of categories; nondiagnostic, non‐neoplastic, benign neoplasm, suspicious for malignancy and malignant. The management is not standardized for the category, salivary gland neoplasm of uncertain malignant potential, as clinical information plays an important role in planning surgical procedures at an individual basis. Further studies will need to be performed using this new classification to help define appropriate management and predict ROM more accurately.

A 4-Year Retrospective Analysis of Salivary Gland Cytopathology Using the Milan System for Reporting Salivary Gland Cytology and Ancillary Studies

“…A high proportion (25.6%) of cases were considered ND. This is somewhat higher than that reported in other studies by [4,[7][8][9][10][11]. This may be related to the method of sample collection.…”

Risk assessment of salivary gland cytological categories of the milan system: a retrospective cytomorphological and immunocytochemical institutional study

“…Poor cellularity, non-mucinous cyst contents, needle positioning outside of the target nodule or improperly prepared and stained smears can be the reasons of nondiagnostic reports (2). Lack of clinical and radiological findings was also identified to be in this category (3).…”

“…Benign neoplasm (n) Malignancy (n) Category I (Non-diagnostic) 3 Inadequate (3). Pleomorphic adenoma (1), Warthin's tumor (1).…”

Implementation of the MILAN system for reporting salivary gland cytopathology: Interobserver concordance and cytohistological correlation of discordant cases

“…Most of the authors have assessed the utility and applicability of MSRSGC primarily focusing on risk stratification of salivary gland cytology. The reported ROM in these studies are mostly concordant with ROM published by the MSRSGC . Layfield et al compared FNA diagnoses from a prior study with specific diagnoses with corresponding MSRSGC diagnoses and found that MSRSGC was comparable with the original reported diagnoses in the majority of cases.…”

“…Since the Milan system was proposed, several studies have shown its diagnostic utility by examining the risk of malignancy (ROM) for each category of the system . Though Hollyfield et al assessed interobserver reliability within MSRSGC focusing only on AUS and SUMP categories but none has studied the overall interobserver variability in MSRSGC that too among pathologists with different years of experience in cytopathology.…”