{"entity":{"id":"yokohama-system-breast-fna","kind":"term","name":"Yokohama System for Reporting Breast Fine-Needle Aspiration Cytopathology","aka":["Yokohama System","IAC Yokohama System"],"tldr":"The Yokohama System puts the result of a needle test on a breast lump into one of five categories: insufficient, benign, atypical, suspicious for cancer, or cancer.","summary":"The International Academy of Cytology published the Yokohama System for breast fine-needle aspiration biopsy cytopathology in 2019 (Field and colleagues, Acta Cytologica). Validation studies describe its five categories: 1 insufficient material, 2 benign, 3 atypical, 4 suspicious for malignancy and 5 malignant, each with a risk of malignancy. In one 63-case series with surgical follow-up the risk was about 2% for benign, 33% for atypical and 100% for suspicious and malignant (Gowri and colleagues, Cureus 2026); small series vary.","asOf":"2026-11-04","links":[{"label":"Field et al., The International Academy of Cytology Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology (Acta Cytol 2019)","url":"https://doi.org/10.1159/000501055"},{"label":"Gowri et al., Validation of the International Academy of Cytology Yokohama System for reporting breast fine-needle aspiration cytopathology (Cureus 2026)","url":"https://doi.org/10.7759/cureus.113225"}],"tags":[],"related":["bi-rads","core-needle-biopsy","who-cytopathology-reporting-systems"],"cancers":["breast-cancer"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Pathology"},"route":"/terms/yokohama-system-breast-fna/","neighbours":{"term":[{"id":"bethesda-category","kind":"term","name":"Bethesda category (thyroid cytology)","route":"/terms/bethesda-category/"},{"id":"bi-rads","kind":"term","name":"BI-RADS (Breast Imaging Reporting and Data System)","route":"/terms/bi-rads/"},{"id":"core-needle-biopsy","kind":"term","name":"Core needle biopsy and fine-needle aspiration (FNA)","route":"/terms/core-needle-biopsy/"},{"id":"who-cytopathology-reporting-systems","kind":"term","name":"WHO Reporting Systems for cytopathology","route":"/terms/who-cytopathology-reporting-systems/"}],"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"}]}}