Comparison of ThinPrep and conventional smears in salivary gland fine-needle aspiration biopsies

BACKGROUND: ThinPrep (TP) cytology for evaluation of nongynecological specimens is being increasingly used. There are few studies comparing TP with conventional smears (CS) in salivary gland (SG) fine-needle aspiration biopsies (FNAB). This study compares diagnostic accuracy and morphology of TP and CS in SG FNABs. METHODS: The authors retrospectively reviewed 98 satisfactory SG FNABs with both TP and CS. All cases had surgical resection. CS and TP slides were assessed for multiple morphological parameters, as well as the ability to make the diagnosis. Chi-square analysis was performed to compare CS and TP. RESULTS: An accurate diagnosis was rendered more commonly with CS compared with TP (57% versus 42%; P = .032), whereas the unsatisfactory rate was greater with TP compared with CS (19% versus 9%; P = .041). The error (4%) and indeterminate (35%) rates for TP were similar to CS. The diagnostic yield was greater for cellular cases, which were more frequent with CS compared with TP, than for cases of low cellularity; the diagnostic yield of cellular TP cases and cellular CS cases was similar. Artifacts (crush, air drying, obscuring blood) were more frequent (12%, 13%, and 27% versus 2%, 0%, and 1%; P