Small cell undifferentiated carcinoma of the minor salivary gland containing exocrine, neuroendocrine, and squamous cells.

The light microscopic, electron microscopic and immunohistochemical features of a small cell undifferentiated carcinoma of the minor salivary gland are presented. The tumor was composed predominantly of undifferentiated small cells with focally admixed neuroendocrine, exocrine and squamous cells, occasionally arranged in an organoid manner. The presence of vasoactive intestinal polypeptide in the tumor was found immunohistochemically. In addition, the tumor cells stained with Grimelius' impregnation. Immunohistochemically the tumor contained cells that reacted positively with the antibodies to carcinoembryonic antigen, 66K keratin polypeptide, or human salivary amylase. These findings indicate that a small cell undifferentiated carcinoma of the minor salivary gland, reported here, exhibits focally multidirectional differentiation as well as neuroendocrine cell derivation.