When should a breast mass be excised in a patient with suspected malignancy or uncertain diagnosis?

When Does a Breast Mass Need to be Excised?

Core needle biopsy is the preferred initial diagnostic approach for suspicious breast masses, but surgical excision is required when core biopsy cannot be performed, when pathology-imaging discordance exists, or when core biopsy reveals specific high-risk histologies including atypical ductal hyperplasia, indeterminate lesions, mucin-producing lesions, potential phyllodes tumors, papillary lesions, or radial scars. 1

Initial Diagnostic Approach

The first step is tissue diagnosis, not immediate excision. Core needle biopsy (under ultrasound, stereotactic, or MRI guidance) achieves 97-99% sensitivity and is strongly preferred over surgical excision as the initial diagnostic method. 1 This approach allows:

• Definitive histologic diagnosis without the cosmetic impact of surgery 1
• Assessment of hormone receptor and HER2 status if malignancy is found 1
• Marker clip placement to localize the lesion if it disappears with neoadjuvant therapy 1

Fine needle aspiration is less accurate than core biopsy for nonpalpable lesions and should generally be avoided. 1

Absolute Indications for Surgical Excision

When Core Biopsy Cannot Be Performed

Surgical excision is appropriate as the primary diagnostic procedure if technical factors prevent core biopsy, including: 1

• Breast too thin to accommodate the biopsy device 1
• Lesion location too superficial or too posterior 1
• Widely scattered calcifications that cannot be accurately targeted 1
• Patient unable to cooperate with the procedure 1

Pathology-Imaging Discordance

Excision is mandatory when the core biopsy result does not match the imaging findings. 1 For example:

• A benign pathology result from a BI-RADS 5 (highly suspicious) spiculated mass is clearly discordant 1
• Even after repeat imaging and additional sampling, persistent discordance requires surgical excision 1

Specific High-Risk Histologies on Core Biopsy

The following core biopsy diagnoses require excisional biopsy due to significant risk of underestimating malignancy: 1

• Atypical ductal hyperplasia (ADH) - Studies demonstrate substantial underestimation of cancer when ADH is diagnosed on core biopsy 1
• Indeterminate lesions (B3 or B4 categories) 1
• Mucin-producing lesions 1
• Potential phyllodes tumors - These cannot be reliably distinguished from fibroadenomas on core biopsy 1, 2
• Papillary lesions 1
• Radial scars 1
• Lobular carcinoma in situ (LCIS) or atypical lobular hyperplasia - Though select concordant cases may be observed 1

The positive predictive value for malignancy is 85% for B4 (suspicious) cores and 25% for B3 (uncertain malignant potential) cores, with certain B3 subcategories reaching 40-46% malignancy rates. 3

Situations Where Observation May Replace Excision

In highly select cases with complete imaging-pathology concordance, observation may substitute for excision: 1

• Concordant LCIS or atypical lobular hyperplasia 1
• Concordant papillomas 1
• Concordant fibroepithelial lesions 1
• Concordant radial scars 1

However, for fibroepithelial lesions with myxoid features, excision should be strongly considered given concern for phyllodes tumor, even with concordance. 2

If observation is chosen, follow-up requires physical examination with or without ultrasound/mammogram every 6-12 months for 1-2 years. 2 Any size increase or rising clinical suspicion mandates immediate excision. 2

Clinical Scenarios Requiring Excision

Palpable Mass with Negative Imaging

Even when mammography and ultrasound are negative (combined risk <3%), a clinically suspicious palpable mass warrants biopsy. 1 Negative imaging should not override a highly suspicious physical finding. 4

Benign Biopsy with Persistent Clinical Concern

When skin changes suggest inflammatory breast cancer but skin biopsy is benign, further evaluation with MRI and possible excision is recommended, as benign skin biopsy does not exclude underlying malignancy. 1

Progressive or Enlarging Lesions

Documented growth of a breast lesion elevates suspicion and requires tissue diagnosis rather than continued observation. 4 This represents a change in BI-RADS category requiring action. 4

Critical Pitfalls to Avoid

• Never delay biopsy of a suspicious mass while awaiting imaging - Imaging should precede biopsy when possible, but clinical suspicion takes precedence 1
• Never accept discordance between pathology and imaging - This requires repeat sampling or excision 1
• Never assume parallel orientation alone indicates benignity when other suspicious features exist (progression, irregular margins, vascularity) 4
• Never rely on short-interval follow-up for lesions showing documented progression - this mandates tissue diagnosis 4
• Never perform diagnostic mammography to decide whether to biopsy a palpable mass - the decision to biopsy should be based on clinical examination 5

Size-Based Considerations

Fibroadenomas larger than 2 cm should be excised, as should any lesion when patient anxiety or request for removal exists - this is recognized as a valid indication. 6 For suspected phyllodes tumors (palpable mass, rapid growth, size >2 cm), excision is recommended. 6