Basal cell adenocarcinoma of the submandibular gland.

Basal cell adenoma is a well recognized histopathologic variant of monomorphic adenoma of salivary gland, but in recent years there have been occasional reports of malignant basal cell tumors of major salivary glands. We present a case report of one such basal cell adenocarcinoma arising in the submandibular gland and discuss the differential diagnosis and distinction from a basal cell adenoma. We also review the published literature on basal cell adenocarcinoma. This is the first case of basal cell adenocarcinoma to be studied in detail by both immunohistochemistry and electron microscopy. There has been debate in the past as to the cell of origin of salivary gland basal cell tumors and specifically as to whether myoepithelial differentiation occurs in these tumors. The immunohistochemical and ultrastructural features of this case provide evidence for a dual population of ductal and myoepithelial cells. A flow cytometric analysis of nuclear deoxyribonucleic acid content showed the presence of DNA aneuploidy within one tissue block.