Histopathologic grading of salivary gland neoplasms: II. Acinic cell carcinomas. Acinic cell carcinomas display varied cytoarchitectural patterns of growth that should allow for formulation of histopathologic grading. Grading of these carcinomas may serve to identify subsets whose biologic behavior is more aggressive than the usually accepted low-grade behavior of acinic cell carcinomas as a group. To that end, a three-level histopathologic grading scheme is presented. 