Parotid gland, Acinic cell carcinoma

Acinic cell carcinoma is a malignant salivary gland neoplasm with a male predominance, that is usually located in the parotid gland. Grossly, this tumor is encapsulated and has a solid gray-white cut surface that is friable and that may show cystic degeneration. On microscopic examination, acinic cell carcinoma may have solid, microcystic, papillary–cystic, or follicular architecture. It is mainly composed of acinic cells with granular or basophilic cytoplasmic appearance. Other cell types that may be present are intercalated duct, clear, vacuolated and nonspecific glandular cells. Immunohistochemical staining for pankeratin, amylase (focal/patchy), alpha 1-antitrypsin, CEA, lactoferrin, and S100 is positive. The tumor is negative for p63, calponin, smooth muscle actin and mammoglobin.