The Milan System for Reporting Salivary Gland Cytopathology: Assessment of Cytohistological Concordance and Risk of Malignancy

Abstract

<b><i>Introduction:</i></b> The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was proposed by the American Society of Cytopathology and the International Academy of Cytology to bring uniformity in the reporting system and the treatment protocol. A wide range of risk of malignancy for each category has been reported by various authors by applying the system. <b><i>Aim:</i></b> We intend to study the cytohistological concordance and the ROM for each of the diagnostic categories of the Milan system. <b><i>Materials and Methods:</i></b> The study included 292 cases of fine-needle aspiration cytology (FNAC) of salivary gland lesions over a period of 3 years. The diagnosis of these cases was reclassified into the 6 categories of the Milan system. The cytohistological concordance and ROM for each category of the Milan system were calculated based on the clinical and histopathological follow-up. <b><i>Results:</i></b> The patients’ age ranged from 3 to 81 years with the mean of 42.65 ± 16.3 years. The cases included 189 (64.7%) parotid, 82 (28.1%) submandibular, and 21 (7.2%) cases of minor salivary gland swellings. Follow-up histopathological diagnosis for 102 cases was available. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated to be 64.28, 97.01, 90, 86.67, and 87.37%, respectively. After reclassification, the number of cases in each category was as follows: category I: 31 (10.62%), category II: 80 (27.4%), category III: 2 (0.68%), category IVA: 143 (48.97%), category IVB: 1 (0.34%), category V: 13 (4.45%), and category VI: 22 (7.53%). The calculated ROM was as follows: category I: 42.86%, category II: 26.67%, category III: 100% category IVA: 10.17%, category IVB: 0%, category V: 71.42%, category VI: 100%. <b><i>Conclusion:</i></b> FNAC is an excellent procedure to differentiate benign from malignant tumors, and MSRSGC is a useful system for risk assessment and deciding the further treatment protocol. Our findings also suggest that in addition to the surgical follow-up, inclusion of the clinical and radiological follow-up may be a better strategy for calculation of ROM, especially for categories I and II.

Evaluation of accuracy of salivary gland fine needle aspirates using the Milan System for Reporting Salivary Gland Cytopathology

“…In the present study, the majority of lesions were from the parotid gland (69.3%), followed by the submandibular gland (29.7%) and minor salivary glands (1%). These findings were similar to most studies done in the literature 7–23 …”

“…Other studies assessed specificity, sensitivity, and accuracy with only the Malignant and SM categories considered as positive results (Table 4). 8,10–19 …”

The Contributory Role of Cell Blocks in Salivary Gland Neoplasms Fine Needle Aspirations Classified by the Milan System for Reporting Salivary Gland Cytology

“…The CBs in these cases were cellular, and either supported the neoplastic diagnosis or were crucial for the neoplastic diagnosis. To summarize other MSRSGC analyses, carcinoma ex PA cases were misinterpreted in a non-neoplastic category in three cases [6,23,35]: in an AUS category in one case [36] and in a SUMP category in only one case [4], but placement in a SUMP category is not generally rated as misinterpretation. Notably, nine cases were in a benign neoplasm IVA category [4,[23][24][25].…”

“…It aimed for better patient care, bringing a practical, evidence-based, user-friendly classification system with characterization and management algorithms [1,2]. Several international studies have stated that the MSRSGC is a reliable tool for salivary gland cytopathology categorization [3][4][5][6][7]. Cell blocks (CBs) are a collection of sediments and visible pieces of tissue from cytological specimens that are concentrated and processed into paraffin blocks, and stained with hematoxylin-eosinike surgical specimens.…”

Cytology of a mass in the hard palate: A diagnostic pitfall

“…Pleomorphic adenoma is the most common benign tumour of the salivary gland 1 . It is known for its protean biphasic morphology, and thus often creates diagnostic dilemmas 2 .…”