Tumors with Myoepithelial Differentiation

Electron micrograph of a myoepithelioma of parotid gland. Portion of a neoplastic myoepithelial cell illustrating (left to right) extracellular space with collagen fibrils and basement membrane, electron-dense attachment plaques on the cell membrane, linear arrays of 6nm actin microfilaments, perinuclear bundles of tonofilaments (indicative of squamous metaplasia), and a portion of the nucleus. (× 22,900) (Courtesy of Dr Robert A. Erlandson, Memorial Sloan-Kettering Cancer Center)