What does a BI-RADS 4 classification indicate?

A BI-RADS 4 classification indicates the presence of a suspicious abnormality in the breast tissue that warrants further investigation. This categorization is part of the Breast Imaging Reporting and Data System (BI-RADS) developed by the American College of Radiology, which helps radiologists categorize mammogram findings based on their level of concern for breast cancer.

When an abnormality is classified as BI-RADS 4, it typically suggests that there is a notable lesion that is not clearly benign, and although the likelihood of cancer is not definitive, it is significant enough (generally between 2% to 95%) to recommend a biopsy for definitive diagnosis. This classification thus serves as a crucial indicator for further diagnostic procedures to clarify the nature of the abnormality and to determine the appropriate management.

In contrast, other classifications like BI-RADS 1 indicate no abnormalities, BI-RADS 2 indicates benign findings, and BI-RADS 3 suggests short-term follow-up due to the low likelihood of malignancy but acknowledges a need for monitoring. Each category, including BI-RADS 4, thereby plays an important role in the overall assessment and management of breast health.