An uncommon benign epithelial tumor, characterized by predominantly unicystic or multicystic growth; there is focal intraluminal papillary proliferation of the lining epithelium. Nearly half occur in the parotid gland. In the minor salivary glands, women are affected more than men. In the major salivary glands, cystadenomas present as slowly enlarging, asymptomatic masses that may be slightly compressible. Cystadenocarcinoma is the malignant counterpart. [from
NCI]