Fine needle aspiration cytology of a myoepithelioma presenting as a thyroid nodule

Myoepitheliomas are rare neoplasms that are typically found in the major and minor salivary glands and represent approximately 1.5% of all salivary gland neoplasms. We present a patient with an exophytic anterior midline neck mass, which was initially believed to be a thyroid isthmus nodule that underwent fine needle aspiration (FNA) biopsy. FNA cytologic evaluation reveals numerous plump spindle cells and a myxoid background, thus raising the possibility of rare benign mixed tumor of the thyroid. However, the resected specimen consists of predominately spindle cells with a minor component of chondromyxoid matrix, and no ductal epithelial cells, favoring a diagnosis of myoepithelioma. Although this lesion clinically and radiologically appeared to arise from the thyroid gland, at the time of resection, it was found to be adjacent to the thyroid isthmus and was ultimately diagnosed as a soft tissue myoepithelioma of the midneck. Diagn. Cytopathol. 2015;43:153–157. © 2014 Wiley Periodicals, Inc.