Screening mammography shows six stippled microcalcifications in a cluster in the upper outer quadrant of the left breast, with no discrete lump. What is the next diagnostic step?

• A. FNA
• B. Excisional biopsy
• C. Needle-localized open biopsy
• D. Core needle biopsy

Answer: (C)

Suspicious microcalcifications seen on screening mammography, especially when they form a clustered, nonpalpable focus, require tissue diagnosis to determine whether DCIS or invasive cancer is present. Fine-needle aspiration tends to be nondiagnostic for calcified lesions and cannot reliably assess architecture or DCIS. A simple excisional biopsy without precise localization risks sampling the wrong area in a nonpalpable lesion and may miss the abnormal focus.

Placing a localizing needle (wire) into the calcified area under imaging guides a surgical biopsy to remove the exact region of interest. This needle-localized open biopsy yields a definitive tissue sample from the calcified cluster with accurate localization, enabling proper histologic assessment and guiding subsequent management.