Myoepithelial Neoplasia of the Submandibular Gland

Tumors of the submandibular gland typically arise from the seromucinous acini, which make up the majority of the gland. The most common benign tumor of this structure is the pleomorphic adenoma, whereas the most common malignancy of the submandibular gland is adenoid cystic carcinoma. We describe an unusual case of a neoplastic process of the myoepithelial cells of the submandibular gland in a middle-aged woman. This rare tumor is most commonly diagnosed in the parotid gland and in the minor salivary glands of the hard palate; a review of the literature uncovered only 5 previous reports of myoepithelioma of the submandibular gland. Distinguishing myoepithelioma from benign pleomorphic adenoma and malignant myoepithelial carcinomas can be challenging. Immunohistochemical staining can help to distinguish between the benign neoplasms, but histologic features remain the "gold standard" for diagnosing the malignant tumors. Increasing use of immunohistochemistry panels to assess parotid neoplasms also suggests that myoepithelioma may be underrecognized.