In an attempt to define more accurately the tumors grouped under the heading of "adenocarcinoma of salivary gland origin," we reviewed the cases in our registry that were classified as adenocarcinoma, carcinoma of salivary gland origin, and infiltrating epithelial salivary gland tumors. Eleven tumors that had certain unique microscopic features in common were identified. These eleven tumors and one that was reviewed in consultation make up the basis of this study. We classified these lesions as lobular carcinoma of salivary gland origin because of their remarkable microscopic resemblance to the breast tumors of the same name. These lesions appear to be of low-grade malignancy and have not recurred or metastasized in any of the eleven cases for which we have follow-up data, at times ranging from 5 to 80 months.