A Bethesda-like system for breast cytopathology: A retrospective assessment two decades on.

Fine-needle aspiration biopsy (FNAB) has been used for many decades in the investigation of breast lesions. Originally, cases were signed out using the categories benign and malignant. The benign category contained specimens showing fibrocystic change as well as benign neoplasms such as fibroadenoma. The malignant category contained carcinomas, lymphomas, and phyllodes tumors with specific diagnoses often given in place of the term malignant. Categorization was less clear when the cytopathologists could not definitively separate benign from malignant. This led to the use of terms, such as atypical, suspicious for malignancy, and atypical suspicious with variable definitions and utilization among cytopathologists. In 1997, a uniform approach to breast FNAB was proposed with well-defined diagnostic categories and criteria. This system foreshadowed the recent International Academy of Cytology Standardized Reporting System for Breast Fine-Needle Aspiration Biopsy. These two systems are compared and contrasted.