ACCURATE diagnosis and adequate treatment of neoplastic disease requires knowledge of its natural life history. While this information is currently available for carcinoma of the breast, uterus, colon, and stomach, some neoplasms of salivary gland origin are not properly identified as malignant tumors. Management of this latter group often leads to a sequence of events where initial optimism soon gives way to doubt and, eventually, pessimism colors the treatment and prognosis. Arising from major and minor salivary gland tissue of the head and neck region is a tumor described variously as "cylindroma," "adenoid cystic carcinoma," "myoepithelioma," "cellular mixed tumor," "adenocarcinoma Grade I," and even "basal cell carcinoma with hyaline stroma." That the clinical and morphological features of this entity are poorly understood is evidenced by the fact that occasionally this lesion has been classified1 and treated2 as a benign tumor. Our experience with 18 cases, and that of