What's the next step for a patient with a BI-RADS (Breast Imaging-Reporting and Data System) 4 lesion, where core needle biopsy showed benign adenosis and duct ectasia?

Management of BI-RADS 4 Lesion with Benign Core Needle Biopsy Results

For a BI-RADS 4 lesion showing benign adenosis and duct ectasia on core needle biopsy, you must determine radiologic-pathologic concordance: if the benign pathology is discordant with the suspicious imaging findings, proceed to surgical excision; if concordant, perform short-term imaging surveillance with physical exam ± ultrasound/mammogram at 6-12 month intervals for 1 year. 1

Critical Decision Point: Radiologic-Pathologic Concordance

The key determinant of next steps is whether your benign pathology result (adenosis and duct ectasia) adequately explains the suspicious BI-RADS 4 imaging features:

If Benign and Image Discordant

• Proceed directly to surgical excision 1
• This is the most common scenario for BI-RADS 4 lesions with benign biopsy results, as the suspicious imaging features that prompted the BI-RADS 4 classification are not adequately explained by simple adenosis and duct ectasia 1
• The NCCN explicitly states that "benign and image discordant" findings require surgical excision to avoid missed malignancy 1

If Benign and Image Concordant

• Perform physical examination ± ultrasound and/or mammogram at 6 or 12 month intervals for 1 year to assess for imaging changes 1
• If the lesion remains stable: return to routine screening 1
• If there is significant increase in size or suspicion: proceed to surgical excision 1

Why Concordance Matters for BI-RADS 4 Lesions

BI-RADS 4 indicates suspicious findings with 2-95% probability of malignancy—these are not "probably benign" lesions 2. The imaging features were concerning enough to warrant biopsy in the first place. Simple benign entities like adenosis and duct ectasia typically do not produce BI-RADS 4-level suspicious features 3. This creates an inherent discordance in most cases.

Common Pitfall to Avoid

Do not simply return to routine screening after a benign biopsy result on a BI-RADS 4 lesion without carefully assessing concordance. The NCCN guidelines explicitly distinguish between:

• Benign concordant findings → short-term follow-up acceptable 1
• Benign discordant findings → surgical excision required 1

The 2018 NCCN guidelines emphasize that excisional biopsy is recommended when core needle biopsy diagnoses "a benign and image discordant lesion" 1

Additional Considerations

Multidisciplinary Review

• Review the case with radiology to formally assess concordance 1
• Consider whether the adenosis is "complex sclerosing adenosis" or if there are other histologic features of concern to the pathologist, as these may require surgical excision regardless of concordance 1

Patient-Specific Factors

• High-risk patients or those with strong family history may warrant lower threshold for surgical excision 4
• Patient anxiety about discordant findings is a reasonable consideration for proceeding to excision 4