Myoepithelial carcinoma of the parotid gland with bilateral thyroid involvement: A case report and review of the literature.

A patient was admitted to hospital with enlarged lobes of the thyroid gland with bilateral cervical lymph node involvement, and surgical excision followed. Histological examination of this specimen revealed a lesion that showed myoepithelial cell differentiation. Primary thyroid and skin appendage tumors were excluded based on clinical examination, conventional histology and immunohistochemistry. A tumor of the right parotid surgically treated in June 2008, approximately 2 years previously, was originally classified as a basal cell adenocarcinoma with focal invasion, but was re-examined. Using immunohistochemistry, the parotid tumor was re-classified as a myoepithelial carcinoma. The thyroid tumor proved to be metastasis from a primary parotid tumor, which was not found in the updated review of the literature. The literature is reviewed, including current knowledge on the histological and immunohistochemical features of myoepithelial carcinoma, with limited data on treatment suggestions.