Epithelial-myoepithelial carcinoma of the parotid - A case of ductal-predominant presentation with cytologic, histologic and ultrastructural correlations

BACKGROUND: The cytologic features of the usual type of epithelial-myoepith elial carcinoma (EMC) of the parotid, with myoepithelial cell predominance, is well described in the cytology literature. In contrast, the cytologic f eatures of ductal- predominant-type EMC has not yet been reported. CASE: An 82-year-old male presented with a 2.7-cm parotid mass of two years ' duration. Fine needle aspiration smears stained with Diff-Quik showed coh esive tissue fragments outlined by metachromatic fibrils scattered in abund ant, smooth, bluish background material. Ultrafast Papanicolaou stain revea led sharply outlined, large ductal cells with smooth, round to oval nuclei, prominent nucleoli and abundant vacuolated cytoplasm; the cells were arran ged tridimensionally in occasional follicles that contained thick secretion s. Neoplastic myoepithelial cells were occasionally seen at the periphery o f tissue fragments, most commonly hidden underneath the neoplastic ductal e pithelium at a slightly different focal plane; the cells had small, oval, d ark nuclei and inconspicuous cell borders. The nuclear area and cell size o f the neoplastic ductal cells was two and three times, respectively, that o f neoplastic myoepithelial cells. CONCLUSION: EMC, depending on the ratio of ductal to myoepithelial cell com ponents, has different cytologic presentations. This case illustrates the d uctal-predominant presentation of EMC.