Plasmacytoid myoepithelioma of the palate.

We present the second case of plasmacytoid myoepithelioma of the palate, which was studied by light and electron microscopy. Apart from plasmacytoid cells, some spindle-shaped cells were observed. Both types of neoplastic cells had myoepithelial features, showing abundant 50-80 A thick filaments in the cytoplasm, and exhibited desmosomal junctions. A light cells with less abundant filaments and better equipped with other organelles were observed. Our findings show that there is no clear-cut distinction between the so-called plasmacytoid myoepithelioma and the spindle and stellate myoepithelioma. We suggest that the ultrastructural appearance of these tumors together with the usual histological criteria for malignancy for may be used to evaluate their prognosis.