Standardized terminology systems in cytopathology

There has been increasing pressure for systemization in cytopathology. Lack of uniformity in categorization, variation in opinion based regional practice, and technologic advancement have created an environment disposed toward creation of more consistent evidence-based approaches to diagnostic problems. This review provides an overview of the major standardized terminology systems in cytology, with historical perspectives and commentary on current uses of these systems. These systems now include gynecologic, thyroid, pancreaticobiliary, urinary, salivary gland, and breast cytology. We summarize major classification systems supported by national and international professional organizations, outlining the structure and goals of each system. Specific benefits and potential pitfalls in the implementation of each system are given. Finally, we address potential criticisms of standardized terminology systems and proposed future directions to continue the evolution of standardized terminology to improve clinical practice.