Soft tissue neoplasms that display myoepithelial differentiation have a range of appearances similar to those arising in the salivary glands, with fascicular or trabecular architecture and epithelioid, clear cell, plasmacytoid, or spindled cytomorphology. Mixed tumors are defined by additionally having ductules or chondroid stroma. This category now includes tumors formerly termed parachordoma, although there are subtle differences between the two entities, and possibly some occurrences of ectomesenchymal chondromyxoid tumor, a very rare lesion of the anterior tongue. Ectopic hamartomatous thymoma (see Chap. 15) also has some features suggestive of myoepithelial differentiation.
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