Cytology of low-grade cribriform cystadenocarcinoma in salivary glands: Cytological and immunohistochemical distinctions from other salivary gland neoplasms

Low-grade cribriform cystadenocarcinoma of the parotid gland is rare malignancy that is classified as a variant of cystadenocarcinoma. In routine cytologic slides from fine-needle aspiration of a parotid gland, we found several pseudopapillary clusters comprising mucus-producing cells. They included a few tumor cells having three-dimensional nuclear atypia and slight hyperchromatism, although most of the tumor cells showed bland nuclei. Our initial cytological diagnosis was: "Indeterminate. Uncertain whether cystadenocarcinoma or cystadenoma." The subsequent histological diagnosis was low-grade cribriform cystadenocarcinoma. Immunohistochemical staining showed diffuse and strong reactivity for S-100; tumor nests that were rimmed by p63(+) cells, which suggests intraductal proliferation. Here, we report cytomorphological findings of this case, and discuss cytological and immunohistochemical distinctions between low-grade cribriform cystadenocarcinoma and other salivary gland tumors, including a review of the literature.