Myoepithelioma
Pronunciation: my-oh-ep-ih-thee-lee-OH-mah
A benign salivary gland neoplasm composed almost exclusively of myoepithelial cells, lacking the ductal component seen in pleomorphic adenoma.
Full Definition
Myoepithelioma is a rare benign tumour of the major and minor salivary glands in which neoplastic myoepithelial cells predominate without significant duct formation, distinguishing it from pleomorphic adenoma. It can display a variety of cell morphologies—spindle, plasmacytoid, epithelioid, or clear—and the correct identification of cell type should be preserved in editorial transcription. The tumour is typically encapsulated and follows a benign clinical course, though malignant transformation to myoepithelial carcinoma has been reported. Editors must not truncate 'myoepithelioma' to 'epithelioma,' which refers to a different entity entirely. IHC markers such as S-100, calponin, and smooth muscle actin are often cited in reports and should be rendered accurately.
Usage
Usage note: Distinguish carefully from 'myoepithelial carcinoma'; the presence or absence of 'carcinoma' changes the diagnosis from benign to malignant.
In Context
- "The parotid mass was excised and diagnosed as a myoepithelioma composed predominantly of plasmacytoid cells with strong S-100 positivity." — Histopathology report
- "Editors should not shorten 'myoepithelioma' to 'epithelioma,' as the latter term has an entirely different diagnostic meaning." — Editorial guidance note