Keratinizing High Grade Squamous Intraepithelial Lesion, a precursor to squamous cell carcinoma of the cervix
The most common benign salivary gland neoplasm, pleomorphic adenomas are composed of two types of cells, epithelial and myoepithelial, in addition to stroma - in varying proportions. The name itself (pleo = many, morph = forms) is derived from the wide spectrum of appearances this tumor can have. In normal salivary glands, ductal epithelial cells line the system that carries secretions from the salivary acini. Myoepithelial cells surround the ducts, having contractile qualities. They also make stromal material, which is the beautiful fibrillary material in the top photo. The myoepithelial cells are the small dark cells intimately associated with the stroma. This neoplasm generally presents as a slow-growing, painless, and well-circumscribed mass, most commonly in the parotid gland.