[344] Quantity Versus Quality: Predicting Malignancy in Salivary Gland Neoplasms.

Meenakshi Bhasin, Gretchen E Galliano. David Geffen School of Medicine at UCLA, Los Angeles, CA

Background: Interpretation of salivary gland neoplasms has limitations because of overlapping morphologic features of benign and malignant lesions and a paucity of helpful ancillary tests. This study was conducted to determine if identifying specific morphologic features could improve diagnosis.
Design: Retrospective review was conducted of all salivary gland FNA from 01/01/05 to 06/01/09. Cases with at least one feature were flagged as “high risk” (HRFNA) regardless of diagnosis. Features were: increased cellularity, basaloid morphology, papillary fragments/morphology, irregular nuclear membranes, increased N/C ratio, mucin, prominent nucleoli, hyperchromasia, and coarse chromatin. Cases with myxoid stroma were excluded in the HRFNA evaluation.
Results: Out of 417 cases, 140 met criteria for HRFNA. For all cases (AC), 60% of false positives were due to over interpretation of a paucicellular specimen, and 64% of false negatives were from non-diagnostic or poorly sampled lesions. Characteristics for AC and HRFNA are in table 1. Outcomes of the HRFNA with respect to morphology are in table 2. 60% of HRFNA with benign outcome had 1 "high risk" feature. 78.8% of cases with benign follow up (FU) had <4 high risk features. However, 46% of the cases with malignant FU had<4 features as well.

Table 1.Diagnostic characteristics
PPV=positive predictive value;NPV=negative predictive value;sens=sensitivity; spec=specificity

Table 2.Cases with high risk features and risk of malignancy
Feature (N)Malignant on SPBenign on SP
Coarse chromatin (11)11(100%)0(0%)
Hyperchromasia (11)10(90%)1(10%)
Irregular nuclear membranes (43)37 (86%)6(14%)
High N/C (29)24(83%)5(17%)
Prominent nucleoli (56)46(82%)10(18%)
Cellularity (62)43 (69%)19(31%)
Basaloid morphology3(25%)9(75%)
Papillary morphology/groups (6)(0)0%6(100%)
SP=surgical follow up

Conclusions: 40% of HRFNA with malignant FU were diagnosed as a benign, low grade tumor, or atypical on FNA. Apparent improved sens and concordance in the HRFNA group was due to lower non-diagnostics or poorly sampled cases. Cellularity standards for interpretation may improve the diagnosis of salivary gland tumors. Cells with basaloid morphology were not at increased risk of malignancy in the absence of other malignant features. Number of features may not be as important as the specific feature and quality of the sampling.
Category: Cytopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 63, Wednesday Afternoon


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