Histopathologic grading of salivary gland neoplasms: III. Adenoid cystic carcinomas.

Histopathologic grading of adenoid cystic carcinomas can provide valuable prognostic information, particularly when the presence or absence of a solid growth architecture is noted. Other growth patterns, exemplified by a tubuloductal or cribriform-cylindromatous differentiation, are associated with a more protracted biologic course and less rapid mortality. A three-tiered grading system based on the three growth patterns of the carcinoma is presented.