Malignant myoepithelioma of the larynx with massive metastatic spread to the liver: an ultrastructural and immunocytochemical study.

A malignant myoepithelioma arising in the submucosal glands of the larynx of a 71-year-old man is reported. The patient presented with a neck mass and massive metastatic involvement of the liver. Light microscopy of a liver biopsy specimen and fine-needle aspiration sample of the neck mass revealed a poorly differentiated carcinoma. Electron microscopic study of a second liver biopsy specimen demonstrated unequivocal features of myoepithelial differentiation; this was further confirmed by the strong cytokeratin and S-100 protein positivity and carcinoembryonic antigen negativity of the tumor cells. Myoepitheliomas are rare tumors, and most reported cases have been benign or of low-grade malignancy. The present case is unique because of its mode of presentation and fulminant course. It also underscores the usefulness of electron microscopy as a diagnostic modality in the work-up of metastatic lesions.