LAUSR

Since the pioneering work of Diane Solomon in developing the initial Bethesda Reporting System for Cervical/Vaginal Cytologic Diagnosis, several similar systems have been proffered by others using a Bethesda-like format. The genius of the original Bethesda system was that it standardized terminology and established diagnostic criteria and follow-up and treatment recommendations. This approach did much to reduce the utilization of confusing and conflicting terminology where a given diagnostic term could have widely different implications for physicians managing their patients. The value of a standardized approach quickly became apparent to practitioners of cytopathology. This realization that standardization of terminology allowed cytopathologists to communicate more effectively among ourselves, and with our clinical colleagues, resulted in many similar systems being proposed in the United States and in other countries. Furthermore, standardized diagnostic categories streamlined the quality control and assurance measures due to easier retrieval of cases from laboratory information systems by diagnostic categories and correlation with subsequent clinical and histopathologic follow-up. Many of these standardized reporting systems developed for other organ systems were either first reported in Diagnostic Cytopathology or analyses of these systems were published in Diagnostic Cytopathology. This special issue will review the most important standardized reporting systems that have been described or discussed in Diagnostic Cytopathology over the past two decades. Each of these systems has attempted to produce a standardized terminology usually associated with rigorous definitions, estimates of malignancy risk, and recommendations for follow-up and patient management. It will not be farfetched to state that Diagnostic Cytopathology, since its inception, has been at the forefront of setting new trends and validation of the existing ones for the practice of cytopathology and limited tissue samples. Some of the detailed studies pertaining to a particular organ system have either led to the recognition of the need for a standardized reporting system or have provided data for calculated risks of malignancy for diagnostic categories. These reporting schemes, in large part, serve as recommendations authored by experts in the subject based on best available evidence for both specialty interest and general cytopathologists. Similar to other guidelines or schema in medicine, these are not set in stone and are updated periodically after new information regarding their applicability and reproducibility in clinical practice is known. This issue of Diagnostic Cytopathology contains seven articles, each focusing on providing the background, framework, and applicability of a tiered reporting scheme for cytopathology specimens. The review by Baloch and LiVolsi places the Bethesda System for Reporting Thyroid Cytology (BSRTC) in its historical context, as well as looking ahead to developments in thyroidology and how they pertain to classification systems for thyroid fine-needle aspiration biopsies (FNABs). The authors review how the BSRTC was proposed during a particularly advantageous time when multiple new practice paradigms were proposed for the diagnosis and clinical management of thyroid nodules. They document the many deficiencies of prior diagnostic systems for thyroid cytopathology and how the first BSRTC addressed these complex issues. The first figure of that review illustrates how the BSRTC functions to categorize cytomorphologic features into useful diagnostic categories. In table 1 of that article, The authors correlate risks of malignancy and recommend management protocols for the diagnostic categories and correlate the updated terminology of the second edition of BSRTC with that of the first. This is a useful exercise to improve our understanding of both the original BSRTC and its recent update. Baloch and LiVolsi document follow-up studies pertaining to the utility of the original BSRTC, including assessment of malignancy risk. Importantly, the authors address problems that were recognized following widespread acceptance of the system, which led to questioning the validity of some portions of the BSRTC. These problems included the development of BSRTC using predominately patient populations drawn from large academic institutions or tertiary referral centers. These populations may have different malignancy risks and patient traits than those that characterize the general population. The recognition that there were relatively wide interobserver variabilities in diagnoses among cytopathologists brought into question the basic premise that a standardized classification system would lead to greater interobserver agreement. These issues lead to the development of the second edition of BSRTC. The second edition addressed major changes in the field of thyroidology, including improvements in imaging and the development of a number of molecular tests aimed at improving diagnostic accuracy. Importantly, the histopathologic evaluation of thyroid neoplasms has developed new diagnostic categories with recognition of “non-invasive follicular tumor with papillary-like nuclei.” This new entity led to a significant change in the risk of malignancy for cases diagnosed as AUS/FLUS, FN/SFN, and suspicious for papillary thyroid carcinoma. The second edition of the BSRTC addressed these salient issues. Finally, the authors succinctly address the future of BSRTC system. Dr Sheaff, in his review of Guidelines for Cytopathologic Diagnosis of Epithelioid and Mixed-Type Malignant Mesotheliomas DOI: 10.1002/dc.24598