Histopathologic grading of salivary gland neoplasms: I. Mucoepidermoid carcinomas. Histopathologic grading of salivary gland neoplasms has been done with various degrees of success and hence various degrees of acceptance among pathologists and otolaryngologists-head and neck surgeons. Given their histopathologic diversity, three carcinomas--mucoepidermoid, adenoid cystic, and acinic cell--would seem to be suitable candidates for grading. In this, the first of a three-part series, the authors present a three-level grading scheme for mucoepidermoid carcinomas. It combines histocytologic and growth features of the carcinomas that independently or together, in other grading proposals, have shown prognostic value. 