Salivary gland cystadenoma and oncocytoma.

Salivary gland cystadenomas and oncocytomas are uncommon benign neoplasms. Cystadenomas are multicystic lesions with a proliferative epithelial lining that may appear papillary, oncocytic, or mucinous while oncocytomas are predominantly solid tumors consisting of large epithelial cells with abundant granular eosinophilic cytoplasm. However, these morphologic features can also be identified in other more frequently encountered benign and malignant salivary gland tumors. Accurate diagnosis is important for appropriate management and follow-up as cystadenomas and oncocytomas are treated by surgical resection and rarely recur or undergo malignant transformation. This review provides an overview of the clinical, pathological, and immunohistochemical features of cystadenomas and oncocytomas, including key diagnostic features and molecular findings to distinguish these benign tumors from their malignant mimics.