Fine-needle aspiration cytology of palisading adenocarcinoma: The first cytology report of a newly described salivary gland neoplasm.

Here, we report the first cytology findings of the newly characterized entity, palisading adenocarcinoma of the salivary gland, diagnosed in the sublingual gland of a 61-year-old female. The liquid-based cytology showed a moderately cellular aspirate containing three-dimensional clusters and trabeculae of tumor cells of various sizes. The cells had dark ovoid nuclei, finely granular chromatin, inconspicuous to punctate nucleoli, and ample cyanophilic cytoplasm with indistinct cell borders. In conventional smears, the cells displayed frequent crush artifacts and anisonucleosis resembling endocrine-type atypia. The background was clean, devoid of secretions, and contained singly dispersed tumor cells with stripped nuclei. Interestingly, concentrically laminated globules of extracellular matrix surrounded by the tumor cells were identified. Mitotic figures and tumor necrotic debris were absent. The cytologic findings correlated with the histologic findings of the excision specimen. The cytologic differential diagnosis and tumor grading of palisading adenocarcinoma were briefly discussed.