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

The Impact of Lesion-Specific and Sampling-Related Factors on Success of Salivary Gland Fine-Needle Aspiration Cytology

PURPOSE

Ultrasound-guided fine-needle aspiration cytology (FNAC) is a widely used diagnostic procedure which facilitates the differentiation of salivary gland lesions. Although the performance of salivary gland FNAC (SG-FNAC) has improved since the introduction of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC), the range of the reported performance is still wide. Therefore, the aim of this study was to determine lesion- and sampling-related factors that influence the success of SG-FNAC.

METHODS

All SG-FNAC cases performed in a tertiary referral hospital between September 1st, 2011, and August 31st, 2022, were retrospectively identified. Demographic, histopathological, lesion-specific, and sampling-related data were retrieved from the clinical charts. Cytopathological reports were categorized according to the MSRSGC. The risk of malignancy (ROM), the performance measures, and factors influencing the success of SG-FNAC were calculated.

RESULTS

Overall, 1289 cases with histopathological follow-up diagnosis (out of 1952 SG-FNACs) were included. The ROM was: non-diagnostic = 23.9%, non-neoplastic = 4.4%, atypia of undetermined significance (AUS) = 34.5%, neoplasm-benign = 1.0%, neoplasm-salivary gland neoplasm of uncertain malignant potential (SUMP) = 15.3%, suspicious for malignancy = 74.1%, malignant = 96.2%. The sensitivity, specificity, accuracy, positive, and negative predictive value for differentiating benign from malignant lesions (excluding lesions categorized as AUS and SUMP) were 87.5%, 97.7%, 96.3%, 85.0%, and 98.1%, respectively. A larger lesion size (OR (95% CI) = 1.21 (1.06-1.39), p = 0.004), a higher number of obtained slides (OR (95% CI) = 1.31 (1.17-1.46), p < 0.001), and the physician performing the FNAC (p = 0.047) were independent predictors for a higher success, while localization of the lesion within the submandibular compared to the parotid gland (OR (95% CI) = 0.38 (0.19-0.77), p = 0.008) was an independent predictor for lower success of SG-FNAC.

CONCLUSION

This is the largest single-center study evaluating SG-FNAC performance to date. It identified independent lesion-and sampling-related factors influencing the success of SG-FNAC. Knowledge of those can improve performance of the procedure.

Salivary gland fine-needle aspiration biopsy: quality assurance results from a tertiary cancer center

INTRODUCTION

Fine-needle aspiration biopsy (FNAB) plays a critical role in the management of patients with salivary gland lesions. A specific diagnosis can be difficult due to the wide range of lesions with overlapping morphologic features, potentially leading to interpretation errors. We analyzed the cytologic-histologic discrepancies identified in the quality assurance program of a major cancer center in cases of salivary gland FNAB and performed a root cause analysis.

MATERIALS AND METHODS

Salivary gland FNAB specimens performed during a 12-year period at a major tertiary cancer center were reviewed. The inclusion criteria for this study included FNAB cases of salivary glands with subsequent histologic or flow cytometry follow up. The cytologic diagnoses for these cases were recategorized according to the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) based on the original reports. The risk of neoplasm and malignancy based on the cases with subsequent resection or flow cytometry and the most common causes of discrepancy were analyzed.

RESULTS

The risk of neoplasm ranged from 41% to 99% and the risk of malignancy ranged from 22% to 99% among the different MSRSGC categories. Lymphoid and myoepithelial rich lesions were the most common miscategorized lesions using the MSRSGC. Reactive changes due to inflammation were associated with overcalls. The most common malignancy in the atypical category was mucoepidermoid carcinomas.

CONCLUSIONS

Myoepithelial and lymphoid rich lesions arising in the salivary gland are associated with a higher risk of misclassification. The use of category IVB in the MSRSGC is appropriate for lesions with abundant myoepithelial cells. Reactive atypia seen in sialadenitis was the most common feature associated with overcall.

Assessment of Risk of Malignancy of Fine-needle Aspiration Cytology in Salivary Gland Lesions Using the Milan System for Reporting Salivary Gland Cytopathology Categorization: A Systematic Review and Meta-analysis

BACKGROUND

Fine-needle aspiration cytology (FNAC) of the salivary gland is crucial in the identification of salivary gland lesions, but the variation in morphological pattern and the overlap of morphological traits can result in erroneous interpretation and affect treatment, making FNAC of the salivary gland problematic. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was created to address these problems.

OBJECTIVES

To ascertain whether the FNAC method using MSRSGC was reliable in predicting the risk of malignancy (ROM) in each category of salivary gland lesions.

MATERIALS AND METHODS

The databases PubMed-MEDLINE, Web of Science, Cochrane, Scopus, and Google Scholar were all searched using pertinent keywords, reference searches, and citation searches. A fixed effect model was used to determine the pooled proportion with a 95% confidence interval (CI). All statistical analyses were performed using Meta Disc and R version 4.0.2 (R Foundation for Statistical Computing).

RESULTS

After reviewing the submissions' abstracts and titles, 58 documents that satisfied the necessary inclusion and exclusion criteria were ultimately selected. A total of 19,652 samples from 19,408 individuals was analyzed, out of which 9,958 samples were available for histopathological follow-up. The pooled ROM for category I was 10%, category II was 5%, category III was 28%, category IV A was 2%, Category IV B was 34%, category V was 91%, and category VI was 99%.

CONCLUSION

Milan System for Reporting Salivary Gland Cytopathology is useful for risk stratification and quality control, confirming its validity and diagnostic utility. Widespread use of MSRSGC would improve the accuracy of salivary gland cytology and lead to better patient care and improved treatment strategies. The results of this study are in consonance with reported values as per MSRSGC except for category V.

CLINICAL SIGNIFICANCE

The MSRSGC which was first reported in 2018 is a very useful tool for proper stratification of ROM in salivary gland FNAC. This study allowed us to validate the ROM values in different categories as reported in MSRSGC.

Application of the Milan System for Reporting Salivary Gland Cytopathology: A systematic review and meta-analysis

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a standard, evidence-based classification system for salivary gland fine-needle aspiration (SG-FNA). Since it was published in 2018, many researchers across the world have applied this uniform reporting system to their cohorts.

METHODS

The authors comprehensively reviewed cohort studies conducted since publication of the MSRSGC and performed a meta-analysis. The risk of neoplasm and the risk of malignancy (ROM) were calculated for each diagnostic category, and their diagnostic efficacy was evaluated.

RESULTS

Thirty-five studies were included in the meta-analysis. The total number of SG-FNAs was 10,706, and 7168 of those had histopathologic follow-up. The ROM for each category was: nondiagnostic, 11.4%; nonneoplastic, 10.9%; atypia of undetermined significance, 30.5%; neoplasm-benign, 2.8%; neoplasm-salivary gland neoplasm of uncertain malignant potential, 37.7%; suspicious for malignancy, 83.8%; and malignant, 97.7%. Low-level heterogeneity was observed in ROM estimation. The sensitivity, specificity, and diagnostic odds ratio for differentiating malignant and benign lesions were 88.0%, 98.5% and 520.3, respectively.

CONCLUSIONS

The reporting of SG-FNA using the MSRSGC demonstrated high diagnostic accuracy. The ROM for each category was generally concordant with the recommendations, except for the suspicious for malignancy category, which was significantly higher than the reference value. The tiered, standardized classification system would benefit the clinical management of salivary gland lesions.

Multiplexed single-cell analysis of FNA allows accurate diagnosis of salivary gland tumors

Diagnosing salivary gland tumors (SGTs) through fine-needle aspiration (FNA) biopsies is challenging due to the overlapping cytomorphologic features between benign and malignant tumors. The authors developed an innovative, multiplexed cycling technology for the rapid analyses of single cells obtained from FNA that can facilitate the molecular analyses and diagnosis of SGTs. Antibodies against 29 protein markers associated with 7 SGT subtypes were validated and chemically modified via custom linker-bio-orthogonal probes (FAST). Single-cell homogenates and FNA samples were profiled by FAST cyclic imaging and computational analysis. A prediction model was generated using a training set of 151,926 cells from primary SGTs (N = 26) and validated on a separate cohort (N = 30). Companion biomarker testing, such as neurotrophic tyrosine receptor kinase (NTRK), was also assessed with the FAST technology. The FAST molecular diagnostic assay was able to distinguish between benign and malignant SGTs with an accuracy of 0.86 for single-cell homogenate samples and 0.88 for FNA samples. Profiling of multiple markers as compared to a single marker increased the diagnostic accuracy (0.82 as compared to 0.65-0.74, respectively), independent of the cell number sampled. NTRK expression was also assessed by the FAST assay, highlighting the potential therapeutic application of this technology. Application of the novel multiplexed single-cell technology facilitates rapid biomarker testing from FNA samples at low cost. The customizable and modular FAST-FNA approach has relevance to multiple pathologies and organ systems where cytologic samples are often scarce and/or indeterminate resulting in improved diagnostic workflows and timely therapeutic clinical decision-making.

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

BACKGROUND

Milan system for reporting salivary gland cytopathology (MSRSGC) was introduced to standardize reporting of salivary gland cytopathology.

METHODS

A retrospective review of ultrasound-guided fine needle biopsy of salivary gland lesions was performed between January 2018 and May 2021 at a community otolaryngology practice. Diagnostic accuracy and rate of diagnostic sialoadenectomy were calculated.

RESULTS

A total of 203 FNAs (fine needle aspiration) were performed in 184 patients. MSRSGC was utilized in 87/203 cytopathology reports, with a diagnostic accuracy of 84%. Descriptive reporting was used in 115 FNAs, with a diagnostic accuracy of 89% (p = 0.68). Sialoadenectomy rate was 41% for MSRSGC compared to 36% in descriptive cytopathology (p = 0.48).

CONCLUSIONS

MSRSGC is as accurate as descriptive cytopathology and the rate of diagnostic sialoadenectomy between both groups is similar in our community. The MSRSGC brings uniformity and standardization to the FNA reporting process.

Nondiagnostic salivary gland FNAs are associated with decreased risk of malignancy compared with "all-comer" patients: Analysis of the Milan System for Reporting Salivary Gland Cytopathology with a focus on Milan I: Nondiagnostic

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) reports a 25% rate of malignancy (ROM) for the Milan I: Nondiagnostic (ND) category. We clarify the ROM of ND salivary gland fine-needle aspirations (SGFNAs) based on our institutional experience and review of the literature.

METHODS

Overall risk of malignancy (OROM) and that for those with surgical/flow cytometric follow-up (FROM) for each category and "all-comers" were calculated for Emory SGFNAs from January 2010 through March 2021. From a literature review of 50 articles using MSRSGC, distribution of diagnoses, rates of follow-up, FROM, and OROM by category were calculated. FROMs and OROMs between ND FNAs and all-comers were compared. Milan I rate was compared with the ratio of Milan I OROM to all-comer OROM.

RESULTS

Of 819 SGFNAs at Emory, 12.8% (n = 105/819) were ND. Thirty-two had known follow-up, with 12 (37.5%) being malignant. Nonmucinous cyst contents accounted for 26.7% of ND SGFNAs (n = 28/105); all 7 with surgical follow-up were benign. Of 50 MSRSGC studies, 18.2% (n = 2384/13,129) of SGFNAs were classified as ND, 26.6% (n = 635/2384) with known follow-up. Total FROM and OROM for ND FNAs (15.7% and 4.1%, respectively) were significantly lower than those for all-comers (24.9% and 11.4%, respectively) (p < .001). There was no relationship between rate of ND SGFNA and ND ROM.

CONCLUSIONS

The ND category is associated with a lower ROM than that of all-comer SGFNA patients. The "true" ROM for ND SGFNAs is likely best estimated by the 4.1% OROM. SGFNAs showing nonmucinous cyst contents have a particularly low ROM. Rate of ND SGFNAs does not influence ND ROM.

Cytologic analysis of vitreous fluids: A retrospective review of our 24 years of experience

BACKGROUND

Cytologic analysis of vitreous fluid is an important component in diagnosis of vitreitis. No standard reporting guidelines exist for these specimens. This study chronicles our 24 years experience and proposes a tentative diagnostic model.

METHODS

Retrospective cytology reports review and database study. Clinical indications, cytologic patterns, ancillary studies performed, and diagnoses were recorded.

RESULTS

176 samples from 160 patients were included and main cytologic patterns are reflected in Table 1. Most fluids were negative for malignancy (88%) and patterns IIB (53%) and IIA (19%) were dominant. The non-diagnostic rate was 7%; atypical and suspicious categories represented <0.5% of fluids tested and only 2% were positive for malignancy (3 intraocular lymphoma and one melanoma). Clinical indications for fluid examination were infection/inflammation (59%), to rule out lymphoma (11%), amyloidosis (3%), melanoma (2%), or to investigate intraocular hemorrhage. Fungal elements were demonstrated in 7 cases. No viral inclusions were appreciated; however, one case was positive for HSV 2 by IHC and 2 were negative by PCR. One case had Gram + cocci. Flow cytometry studies were suboptimal in 6 fluids, negative for an aberrant lymphocyte population in 11, and positive for high grade lymphoma in 3 cases. Atypical, suspicious and positive for melanoma were reported in 3 samples. Amyloid was identified in 1 aspirate.

CONCLUSIONS

Cytologic analysis of vitreous fluid is a useful tool. Modern techniques like flow cytometry and PCR testing further expand the diagnostic possibilities. Standardization of diagnostic terminology will aid clinicians caring for patients suffering from ocular disease.