Breast Fine Needle Aspiration Cytology: Introduction to the Yokohama Classification

Palpable breast lumps or non-palpable, imaging detected breast lesions require tissue sampling for diagnosis. Current practice recommendations include fine needle aspiration cytology or core needle biopsy samples as a method to obtain those samples. Correlation with clinical and radiographic features is essential to determine the appropriate therapeutic plan for the patient. Based on practice patterns and institutional preference, breast cytology is frequently used as a minimally invasive, fast, and cost-effective method. The Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology represents a contemporary guide to diagnosis of breast fine needle aspiration cytology with diagnostic criteria, risk-of-malignancy assessment, and management recommendations. The diagnostic categories consist of insufficient, benign, atypical, suspicious, and malignant breast cytology samples. Risk-of-malignancy data from literature and studies is included.