Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Apr;129(4):291-303.
doi: 10.1002/cncy.22382. Epub 2020 Nov 2.

Putting morphology to the test: An established classification scheme reliably stratifies salivary gland cytology by risk of malignancy with substantial interobserver agreement

Daniel J Lubin  1 , Christopher C Griffith  2 , Darren J Buonocore  3 , Xiao-Jun Wei  3 , Oscar Lin  3
Affiliations

Putting morphology to the test: An established classification scheme reliably stratifies salivary gland cytology by risk of malignancy with substantial interobserver agreement

Daniel J Lubin et al. Cancer Cytopathol. 2021 Apr.

Abstract

Background: The Milan System for Reporting Salivary Gland Cytopathology describes several salivary gland fine-needle aspiration cytology (SGFNAC) morphologies developed by Griffith et al. Basaloid neoplasms are pleomorphic (PB) or monomorphic with fibrillary (MBFib), hyaline (MBHy), or other (MBOther) matrix. Oncocytoid neoplasms can be pleomorphic (PO), demonstrate granular and/or vacuolated cytoplasm (OGV), or be monomorphic with mucinous (MOMuc), cystic (MOCyst), or other (MOOther) background. In the current study, the authors explore interobserver agreement (IOA) and risk of malignancy (ROM) for these subcategories.

Methods: The study included 169 SGFNAC cases with surgical follow-up. Four reviewers categorized these cases using the criteria of Griffith et al. with consensus determined by majority. For all morphologic categories, IOA (using the Fleiss kappa) and ROM were calculated.

Results: ROMs for basaloid categories were: PB: 100% (1 of 1 case); MBHy: 71.4% (5 of 7 cases); MBFib: 50.0% (3 of 6 cases); and MBOther: 47.4% (9 of 19 cases). ROMs for oncocytoid neoplasms were: OGV: 100% (10 of 10 cases); MOMuc: 92.3% (12 of 13 cases); PO: 88.9% (8 of 9 cases); MOOther: 33.3% (5 of 15 cases); and MOCyst: 0 (0 of 1 case). The system demonstrated substantial agreement overall (κ = 0.69). For basaloid neoplasms, the IOA results were: MBHy: κ = 0.59; MBFib: κ = 0.41; MBOther: κ = 0.41; and PB: κ = 0.11. For oncocytoid neoplasms, the IOA results were: MOMuc: κ = 0.88; OGV: κ = 0.67; PO: κ = 0.63; MOOther: κ = 0.57; and MOCyst: κ = 0.18.

Conclusions: The SGFNAC scheme proposed by Griffith et al. and incorporated into the Milan System for Reporting Salivary Gland Cytopathology demonstrated substantial agreement overall, with particularly high agreement for the MOMuc, OGV, PO, and MBHy categories. The PB and MOCyst categories demonstrated slight agreement and may be improved by revised criteria. The PB, PO, MOMuc, and OGV categories demonstrated high ROM, and the latter 2 categories might best be classified as suspicious for malignancy.

Keywords: Milan System for Reporting Salivary Gland Cytopathology (Milan System); basaloid; fine-needle aspiration; interobserver agreement; oncocytoid; reproducibility; risk of malignancy; salivary gland cytopathology.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Original Griffith categorization scheme
Figure 2:
Figure 2:
Pleomorphic basaloid neoplasm. This was the single case with a consensus designation of pleomorphic basaloid neoplasm. Note the significant anisonucleosis of the smaller group of cells. Follow-up revealed myoepithelial carcinoma.
Figure 3:
Figure 3:
Monomorphic basaloid neoplasm with fibrillary matrix. This case revealed cellular smears with only minimal amounts (<25%) of pink fibrillary matrix. Follow-up revealed pleomorphic adenoma.
Figure 4:
Figure 4:
Monomorphic basaloid neoplasm with hyaline matrix. Note the abundant dense pink globules of matrix material. Follow-up revealed adenoid cystic carcinoma.
Figure 5:
Figure 5:
Monomorphic basaloid neoplasm with mixed/other matrix. This example demonstrates bland basaloid cells without any appreciable matrix material. Follow-up revealed basal cell adenocarcinoma.
Figures 6a and 6b:
Figures 6a and 6b:
Two cases categorized as oncocytoid neoplasm with granular/vacuolated cytoplasm. The first case (6a) demonstrates sheets of cells with fragile granular to microvacuolated cytoplasm. Note the numerous naked nuclei. Follow-up revealed an acinic cell carcinoma. The second case (6b) shows cells with abundant cytoplasm with frequent microvacuoles and a single cell distended with a massive pink cytoplasmic vacuole. Follow-up revealed a secretory carcinoma.
Figure 7:
Figure 7:
Pleomorphic oncocytoid neoplasm. Cells with moderate amounts of pink cytoplasm demonstrating marked nuclear pleomorphism. Follow-up revealed salivary duct carcinoma.
Figure 8:
Figure 8:
Monomorphic oncocytoid neoplasm with mucinous background. Note the abundant dense pink mucin in the background. Follow-up revealed mucoepidermoid carcinoma.
Figure 9:
Figure 9:
Monomorphic oncocytoid neoplasm with other background. A pure population of oncocytes without a cystic or mucinous background. Follow-up revealed an oncocytoma.
Figure 10:
Figure 10:
Monomorphic oncocytoid neoplasm with cyst contents background. Follow-up revealed an oncocytic cystadenoma.
See this image and copyright information in PMC

References

    1. Rossi ED, Faquin WC, Baloch Z, Barkan GA, Foschini MP, Pusztaszeri M, et al.The Milan System for Reporting Salivary Gland Cytopathology: Analysis and suggestions of initial survey. Cancer Cytopathol. 2017;125(10):757–66. - PubMed
    1. Schmidt RL, Hunt JP, Hall BJ, Wilson AR, Layfield LJ. A systematic review and meta-analysis of the diagnostic accuracy of frozen section for parotid gland lesions. Am J Clin Pathol. 2011;136(5):729–38. - PubMed
    1. Liu CC, Jethwa AR, Khariwala SS, Johnson J, Shin JJ. Sensitivity, Specificity, and Posttest Probability of Parotid Fine-Needle Aspiration: A Systematic Review and Meta-analysis. Otolaryngol - Head Neck Surg (United States). 2016;154(1):9–23. - PMC - PubMed
    1. Johnson DN, Onenerk M, Krane JF, Rossi ED, Baloch Z, Barkan G, et al.Cytologic grading of primary malignant salivary gland tumors: A blinded review by an international panel. Cancer Cytopathol. 2020;1–11. - PMC - PubMed
    1. Griffith CC, Pai RK, Schneider F, Duvvuri U, Ferris RL, Johnson JT, et al.Salivary Gland Tumor Fine-Needle Aspiration Cytology: A Proposal for a Risk Stratification Classification. Am J Clin Pathol. 2015;143(6):839–53. - PMC - PubMed

Publication types