Salivary Gland Tumor Fine-Needle Aspiration Cytology

Abstract

Objectives Fine-needle aspiration (FNA) is useful in the evaluation of salivary gland tumors, but currently no standard terminology or risk stratification model exists. Methods FNA smears were reviewed and categorized based on cytonuclear features, stromal characteristics, and background characteristics. Risk of malignancy was calculated for each category. Classifications as benign, neoplasm of uncertain malignant potential (NUMP), suspicious for malignancy, and positive for malignancy were used to aggregate categories into similar risk groups. Results Categorization of salivary gland aspirates into morphologic categories resulted in the expected risk stratification. Grouping of categories maintained risk stratification, providing classes with malignancy risk as follows: benign, 2%; NUMP, 18%; suspicious for malignancy, 76%; and positive for malignancy, 100%. Conclusions Salivary gland FNA categorization into commonly encountered morphologic categories provides risk stratification, which translates to a simplified classification scheme of benign, NUMP, suspicious, and positive for malignancy similar to the paradigm in other organ systems.

A pattern‐based risk‐stratification scheme for salivary gland cytology: A multi‐institutional, interobserver variability study to determine applicability

“…“Warthin tumor” can be maintained as a separate pattern, as the ROM in this study and the prior proposal was 0% (0 of 45) 12 indicating that the diagnosis of WT can be made confidently when suitable diagnostic features are present. Such a category could allow some patients to more easily avoid surgery, depending on the clinical situation.…”

“…Using these aggregated ROM, the current study shows a similar risk stratification profile to that reported in the original proposal, and some categories show nearly identical risks of malignancy. 12 Specifically, pattern categories with nearly identical ROM include the basaloid neoplasm with fibrillary stroma (14.3% compared to 15.4%), basaloid neoplasm with mixed/hyaline stroma (60% in both studies), Warthin tumor (0% in both studies), oncocytoid neoplasm with mucinous background (80% in both studies), oncocytoid neoplasm with granular/vacuolated cytoplasm (81.3% compared to 84.6%) and pleomorphic oncocytoid neoplasm (100% in both studies).…”

“…Despite these limitations, the findings do suggest that the different patterns have the potential to result in risk stratification for salivary gland tumors, as shown in the prior initial larger study based on histological follow-up. 12 Additional studies will be needed to more accurately define the ROM in actual practice.…”

“…In cases considered at least suspicious for neoplasm, a pattern was assigned using the pattern-based risk stratification scheme proposed by Griffith et al (Table 1, first column). 12 One author (CCG) was involved in the original development and proposal of this pattern based scheme and the other observers reviewed the original proposal article and a summary chart describing the pattern based classification for those lesions deemed at least neoplastic; however, no specific training was given in the recognition of these patterns. In order to examine the effect of simplification in this proposed pattern-based system, several categories were condensed on secondary analysis (Table 1, second column).…”

“…12, 13 Briefly, this pattern-based schema separates basaloid tumors from oncocytoid tumors (Table 1, first column). Basaloid tumors are further divided based on the quality of the stroma, such that those neoplasms lacking clearly identifiable and uniformly fibrillary stroma have a higher ROM than those with definitive and abundant fibrillary stroma occupying more than three-fourths of the material.…”