Myoepithelial cell adenoma of the parotid gland: A light and ultrastructural study

Abstract

Light, histochemical, and ultrastructural features of a myoepithelial cell adenoma of the parotid gland are described. Ultrastructurally, the neoplasm was almost entirely composed of myoepithelium. The spindle-shaped myoepithelial cells and their processes were filled with longitudinally oriented myofilaments with characteristic densities along their course and marginal attachment plaques. The tumor cells were interconnected by desmosomes. The role of myoepithelium in the genesis of some salivary gland tumors is discussed.

Current Status of Histogenetic and Morphogenetic Concepts of Salivary Gland Tumorigenesis

“…Subpopulations of myoepithelial cells have been identified in human salivary and mammary glands, a small number of which immunostain for GFAP (Zarbo et al, 1988;Viale et al, 1991). These observations emphasize the limits of functional information available to us concerning normal myoepithelium and assist in 645 appreciating the variable differentiation evident in the myoepithelial-like and other nonluminal cells of salivary gland tumors (Chaudhry et al, 1982;Dardick et al, 1983;Erlandson et al, 1984;van Nostrand, 1987, 1990;Mackay et al, 1988;Zarbo et al, 1988).…”

Myoepitheliomas of the head and neck: Case report and review

“…To merit this appellation, some authorepithelial and myoepithelial cells-the classical pleoities require that a tumor be composed "entirely" of morphic adenoma. myoepithelial cells [7], while others require it to be It is our opinion, as well as that of Dardick et al, that composed "almost entirely" of these cells [9,16]. Ac-the salivary adenomas "form a spectrum with monocording to the latter group, the presence of a few salivary morphic adenoma and myoepithelioma at the extremes ducts in an otherwise typical lesion does not invalidate and a wide range of pleomorphic adenoma between, the diagnosis.…”

Immunohistochemical expression of S-100 protein in reactive and neoplastic myoepithelial cells of variant salivary pleomorphic adenomas.

“…The progenitor cells of pleomorphic adenomas of human salivary glands have been suggested to be either ductal epithelial cells or modified myoepithelial cells (2,4,5,7,(15)(16)(17)(18). In the case of the former, the most prospective origin are those (2), and that the plasmacytoid type cells thin filaments (17), the modified or transformed myoepithelial cells in them contain also myofibrils, and that their ergastoplasm indicates the production of proteins secreted into the interstitium (7).…”

“…Tumorigenesis of pleomorphic adenoma is subsequently evident to proliferate to either epithelial components or myoepithelial cells having both biologic properties of smooth muscle-like and mesenchyme (2,7,18). In this regard, both clear cell adenoma of monomorphic adenoma and adenoid cystic carcinoma of salivary glands have a peculiar differentiation from the myoepithelial cells (15,17), and mucoid secretion or hyaline stroma in pleomorphic adenoma is also from the myoepitheliumderived cells (4).…”