J Pathol Transl Med.  2020 Sep;54(5):419-425. 10.4132/jptm.2020.06.09.

A retrospective cytohistological correlation of fine-needle aspiration cytology with classification by the Milan System for Reporting Salivary Gland Cytopathology

• Park JH
• Cha YJ
• Seo JY
• Lim JY
• Hong SW

• KMID: 2506275
• DOI: http://doi.org/10.4132/jptm.2020.06.09

Abstract

Background
Before publication of the new classification system named the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) in 2018, there was no standard classification for salivary gland lesions obtained by fine-needle aspiration (FNA). We therefore aimed to evaluate the diagnostic utility of this system by retrospectively reviewing FNA samples using the MSRSGC and to determine their risk of developing into neoplasms and becoming malignant.
Methods
Retrospective slide review and classification of salivary gland FNAs obtained over a 6-year period (2013–2018) at a single center were performed by two pathologists. The risks of neoplasm and malignancy for each category also were calculated.
Results
This study surveyed 374 FNAs (371 patients) performed over a six-year period and selected 148 cases that included documented surgical follow-up (39.6%). Among the surgically treated cases, the distributions of FNA categories were as follows: non-diagnostic (ND; 16.9%), non-neoplastic (NN; 2.7%), atypia of undetermined significance (AUS; 3.4%), benign (BN; 54.7%), salivary gland neoplasm of uncertain malignant potential (SUMP; 10.1%), suspicious for malignancy (SM; 6.8%), and malignant (M; 5.4%). The risk of malignancy (ROM) was 24.0% for ND, 0% for NN, 40.0% for AUS, 2.5% for BN, 46.7% for SUMP, 100% for SM, and 87.5% for M. The overall diagnostic accuracy was 95.9% (142/148 cases).
Conclusions
The newly proposed MSRSGC appears to be a reliable system for classification of salivary gland lesions according to the associated ROM.

Keyword

Salivary gland; Fine-needle aspiration; The Milan System for Reporting Salivary Gland Cytopathology; Risk of malignancy

Figure

• 

  Fig. 1. Distribution of malignant (A) and benign (B) neoplasms in category I fine-needle aspiration samples. PA, pleomorphic adenoma; WT, Warthin tumor; MEC, mucoepidermoid carcinoma; EMC, epithelial myoepithelial carcinoma; ACC, acinic cell carcinoma; DLBCL, diffuse large B-cell lymphoma; BCA, basal cell adenoma.

• 

  Fig. 2. Images of one of the false positive cases (atypical pleomorphic adenoma). (A) Fine-needle aspiration revealed highly atypical cells suspicious for malignant neoplasm. (B) Higher magnification of the mass showing atypical cells. (C) A lower magnification of the atypical pleomorphic adenoma without capsule invasion.

Reference

References

1. Layfield LJ, Gopez E, Hirschowitz S. Cost efficiency analysis for fine-needle aspiration in the workup of parotid and submandibular gland nodules. Diagn Cytopathol. 2006; 34:734–8.

2. Mairembam P, Jay A, Beale T, et al. Salivary gland FNA cytology: role as a triage tool and an approach to pitfalls in cytomorphology. Cytopathology. 2016; 27:91–6.

3. Wang H, Fundakowski C, Khurana JS, Jhala N. Fine-needle aspiration biopsy of salivary gland lesions. Arch Pathol Lab Med. 2015; 139:1491–7.

4. Seethala RR, Griffith CC. Molecular pathology: predictive, prognostic, and diagnostic markers in salivary gland tumors. Surg Pathol Clin. 2016; 9:339–52.

5. Pusztaszeri MP, Garcia JJ, Faquin WC. Salivary gland FNA: new markers and new opportunities for improved diagnosis. Cancer Cytopathol. 2016; 124:307–16.

6. Pusztaszeri MP, Faquin WC. Update in salivary gland cytopathology: Recent molecular advances and diagnostic applications. Semin Diagn Pathol. 2015; 32:264–74.

7. Goyal S, Sharma S, Diwaker P. Diagnostic role and limitations of FNAC in oral and jaw swellings. Diagn Cytopathol. 2015; 43:810–8.

8. Schindler S, Nayar R, Dutra J, Bedrossian CW. Diagnostic challenges in aspiration cytology of the salivary glands. Semin Diagn Pathol. 2001; 18:124–46.

9. Ashraf A, Shaikh AS, Kamal F, Sarfraz R, Bukhari MH. Diagnostic reliability of FNAC for salivary gland swellings: a comparative study. Diagn Cytopathol. 2010; 38:499–504.

10. Jain R, Gupta R, Kudesia M, Singh S. Fine needle aspiration cytology in diagnosis of salivary gland lesions: a study with histologic comparison. Cytojournal. 2013; 10:5.

11. Colella G, Cannavale R, Flamminio F, Foschini MP. Fine-needle aspiration cytology of salivary gland lesions: a systematic review. J Oral Maxillofac Surg. 2010; 68:2146–53.

12. Rossi ED, Baloch Z, Pusztaszeri M, Faquin WC. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC): an ASCIAC-sponsored system for reporting salivary gland fine-needle aspiration. J Am Soc Cytopathol. 2018; 7:111–8.

13. Rossi ED, Faquin WC, Baloch Z, et al. The Milan System for Reporting Salivary Gland Cytopathology: analysis and suggestions of initial survey. Cancer Cytopathol. 2017; 125:757–66.

14. Song SJ, Shafique K, Wong LQ, LiVolsi VA, Montone KT, Baloch Z. The utility of the Milan System as a risk stratification tool for salivary gland fine needle aspiration cytology specimens. Cytopathology. 2019; 30:91–8.

15. Viswanathan K, Sung S, Scognamiglio T, Yang GC, Siddiqui MT, Rao RA. The role of the Milan System for Reporting Salivary Gland Cytopathology: a 5-year institutional experience. Cancer Cytopathol. 2018; 126:541–51.

16. Rossi ED, Wong LQ, Bizzarro T, et al. The impact of FNAC in the management of salivary gland lesions: institutional experiences leading to a risk-based classification scheme. Cancer Cytopathol. 2016; 124:388–96.

17. Rohilla M, Singh P, Rajwanshi A, et al. Three-year cytohistological correlation of salivary gland FNA cytology at a tertiary center with the application of the Milan system for risk stratification. Cancer Cytopathol. 2017; 125:767–75.

18. Park W, Bae H, Park MH, et al. Risk of high-grade malignancy in parotid gland tumors as classified by the Milan System for Reporting Salivary Gland Cytopathology. J Oral Pathol Med. 2019; 48:222–31.

19. Thiryayi SA, Low YX, Shelton D, Narine N, Slater D, Rana DN. A retrospective 3-year study of salivary gland FNAC with categorisation using the Milan reporting system. Cytopathology. 2018; 29:343–8.

20. Faquin WC, Rossi ED, Baloch Z, et al. The Milan System for Reporting Salivary Gland Cytopathology. New York: Springer;2018.

21. Edwards PC, Wasserman P. Evaluation of cystic salivary gland lesions by fine needle aspiration: an analysis of 21 cases. Acta Cytol. 2005; 49:489–94.

22. Frable MA, Frable WJ. Fine-needle aspiration biopsy of salivary glands. Laryngoscope. 1991; 101:245–9.

23. Joseph TP, Joseph CP, Jayalakshmy PS, Poothiode U. Diagnostic challenges in cytology of mucoepidermoid carcinoma: report of 6 cases with histopathological correlation. J Cytol. 2015; 32:21–4.