Myoepithelial carcinoma: A report of two cases and review of the literature

Objectives: Myoepithelial carcinoma is a rare neoplasm of salivary gland origin. The tumor cells demonstrate morphologic, immunohistochemical and electron-microscopic features of myoepithelial cells and lack ductal and acinar differentiation. Only one series of 10 compiled cases exists in the literature. An additional 7 cases have been reported. The clinical behavior is that of a malignant tumor with a tendency for local recurrence and a propensity for distant metastases. Material and Methods: We add our experience of 2 cases of myoepithelial carcinoma. Both cases arose in the parotid gland. A myoepithelioma had been excised via a parotidectomy several years prior to the presentation with myoepithelial carcinoma. In addition one of the patients demonstrated distant osseous metastases. To our knowledge neither of these features have previously been reported in the literature. Results and Conclusions: The histological features of myoepithelioma and myoepithelial carcinoma are compared. The histogenesis of these unusual tumors, natural history and treatment are discussed.