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Atlas of breast cancer early detection

Reporting and final assessment categories – Final assessment categories – BI-RADS 4


BI-RADS 4 indicates suspicious mammography findings that need further biopsy for confirmation. BI-RADS 4 lesions do not show morphological features characteristic of breast cancer but have a probability of being malignant. The probability of malignancy varies from 2% to 95%. BI-RADS 4 is divided into 4A, 4B, and 4C:
  • BI-RADS 4A lesions include partly circumscribed masses, solitary complex cysts, or suspicious axillary lymph nodes without breast abnormalities .
  • BI-RADS 4B lesions include pleomorphic microcalcifications, grouped calcifications, or solid masses of indeterminate morphology .
  • BI-RADS 4C lesions include new groups of calcifications or new indistinct irregular masses .
Biopsy is recommended for findings in this category.


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