Liquid-based cytology (LBC) with immunocytochemical staining improves fine-needle aspiration cytology (FNA) performance for salivary gland tumors

Liquid-based cytology (LBC), now used globally for the head and neck region, has been used at our hospital since 2011. This study was designed to analyze the efficacy of LBC with immunocytochemical staining on preoperative diagnosis of salivary gland tumors. This retrospective analysis of fine-needle aspiration (FNA) performance for salivary gland tumors was conducted at Fukui University Hospital. Salivary gland tumor operations conducted during April 2006 – December 2010 (84 cases) were classified as the Conventional Smear (CS) group, which were diagnosed morphologically by Papanicolaou and Giemsa staining. Those done during January 2012 – April 2017 (112 cases) were classified as the LBC group, which were diagnosed using LBC samples with immunocytochemical staining. The FNA results and pathological diagnosis of both groups were analyzed to calculate the FNA performance. Compared to the CS group, cases of inadequate and indeterminate FNA sample were not reduced significantly by LBC with immunocytochemical staining. As for FNA performance, the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CS group were, respectively, 88.7%, 53.3%, 100%, 100%, and 87.0%. Those of LBC group were all 100%, representing significant improvement over the CS group. Analysis results indicated the usefulness of LBC with immunocytochemical staining for preoperative diagnosis of salivary gland tumors.