The Yokohama System for Reporting Breast Cytopathology
image: (a) Fibroadenoma shows three-dimensional clusters of ductal epithelial cells with an antler-like configuration and many dispersed bipolar myoepithelial cells or small naked nuclei in the background (×200). (b) Intraductal papilloma shows papillary structure of ductal epithelial cells with fibrovascular cores and some background dispersed myoepithelial cells (×40). (c) Reparative changes in a case of fat necrosis. The presence of cellular atypia may lead to overinterpretation (×400). (d) Granulomatous mastitis shows multinucleated giant cells, macrophages, mixed inflammatory cells, and debris (×400).
Credit: Wendong Yu
The International Academy of Cytology (IAC) Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy (FNAB) Cytology was developed to standardize breast cytology reporting, improve communication between cytopathologists and clinicians, and facilitate optimal patient care. This system, initiated at the Yokohama International Congress of Cytology in 2016, provides a structured approach to classify breast lesions based on their risk of malignancy and aids in clinical decision-making.
Background and Development
Breast FNAB is a widely used diagnostic tool, particularly in developing countries, due to its simplicity, cost-effectiveness, and minimal complications. With a reported sensitivity of 91–92% and a specificity of approximately 98%, FNAB is a reliable method for diagnosing breast lesions . However, it cannot assess invasion status or intact histologic architecture, which limits its use in certain contexts. Despite these limitations, FNAB remains an essential component of breast cancer evaluation, especially when combined with clinical and radiologic information (the "triple test").
The Yokohama Reporting System
The Yokohama System classifies breast FNAB results into five categories: insufficient/inadequate, benign, atypical, suspicious for malignancy, and malignant. Each category has specific criteria and recommended management strategies based on the risk of malignancy (ROM).
- Insufficient/Inadequate: This category includes smears that are too sparsely cellular or poorly prepared to allow for a definitive cytomorphological diagnosis. Proper training and techniques, including the use of ultrasound guidance and rapid on-site evaluation (ROSE), are recommended to minimize inadequate samples.
- Benign: Lesions classified as benign show unequivocally benign cytologic features. Common benign lesions include fibrocystic changes, fibroadenoma, and normal breast tissue. Management typically involves clinical and radiologic follow-up if the findings are consistent with benign disease.
- Atypical: The atypical category includes samples with cytologic features that do not clearly indicate benign or malignant processes. These cases often require further investigation, including repeat FNAB or core needle biopsy (CNB), to establish a definitive diagnosis.
- Suspicious for Malignancy: Lesions in this category exhibit cytologic features suggestive of malignancy but are not definitive. Such cases generally warrant a CNB to confirm the diagnosis and guide appropriate treatment.
- Malignant: This category is reserved for cases with cytologic features diagnostic of malignancy. Management typically includes a review of clinical and radiologic findings, followed by CNB to plan further treatment.
Clinical Implications and Future Directions
The implementation of the Yokohama System has been successful in various institutions worldwide, demonstrating its efficacy in improving breast FNAB reporting and patient management. The system's reliance on comprehensive clinical and radiologic information ensures accurate diagnoses and optimal care. Future studies and modifications will continue to refine the system, ensuring its adaptability to evolving clinical practices and technological advancements.
Conclusions
The IAC Yokohama System for Reporting Breast Cytopathology represents a significant advancement in the standardization of breast FNAB reporting. By providing a structured approach to classify breast lesions and recommending appropriate management strategies, the system enhances communication between cytopathologists and clinicians and improves patient care. Continued evaluation and refinement of the system will ensure its ongoing relevance and effectiveness in the ever-evolving field of breast cancer diagnosis and treatment.
Full text
https://www.xiahepublishing.com/2771-165X/JCTP-2023-00006
The study was recently published in the Journal of Clinical and Translational Pathology.
Journal of Clinical and Translational Pathology (JCTP) is the official scientific journal of the Chinese American Pathologists Association (CAPA). It publishes high quality peer-reviewed original research, reviews, perspectives, commentaries, and letters that are pertinent to clinical and translational pathology, including but not limited to anatomic pathology and clinical pathology. Basic scientific research on pathogenesis of diseases as well as application of pathology-related diagnostic techniques or methodologies also fit the scope of the JCTP.
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