Diagnosis of acinic cell carcinoma of the salivary gland on cytology specimens: Role of NOR‐1 (NR4A3) immunohistochemistry

Abstract

AbstractObjectivesAcinic cell carcinoma (AcCC) is often a challenging diagnosis on cytology. Recently, NOR‐1 (NR4A3) has been demonstrated as a sensitive and specific marker for AcCC. Therefore, we conducted this study to evaluate NOR‐1 expression in AcCC cytology specimens and to compare its reactivity in other salivary gland tumours (non‐AcCC).MethodsWe retrospectively reviewed our database and selected cytology cases with available cell blocks, including 10 AcCC and 24 non‐AcCC tumours (12 benign tumours and 12 malignant tumours). NOR‐1 (1:50 dilution; SC393902 [H‐7]; Santa Cruz Biotech) immunohistochemistry (IHC) was performed on all cases.ResultsAll AcCC cases except two (2/10, 80%) showed positive nuclear staining of variable intensity for NOR‐1, with the majority of cases (75%) demonstrating at least moderately intense nuclear expression. All non‐AcCC cases were negative for NOR‐1, demonstrating a specificity of 100%.ConclusionWe conclude that NOR‐1 IHC is sensitive and very specific on cytology specimens and is able to distinguish AcCC from its mimickers reliably and classify them appropriately for further management.