Acinic cell carcinoma of the parotid gland with neuroendocrine differentiation.

Acinic cell carcinoma (ACC) is a malignant salivary gland tumor characterized by tumor cells displaying acinar features. Usually presenting as a slow-growing tumor, ACC, however, may show dedifferentiation to a higher grade including neuroendocrine carcinoma. In addition, ACC may rarely show focal neuroendocrine differentiation without any frank evidence of neuroendocrine carcinoma. We describe such a case of ACC of the parotid gland in a 65-year-old female, which showed neuroendocrine differentiation. The diagnostic clues, immunohistochemistry panel, and prognostic and treatment aspects are also presented.