Microcystic Calcifications at Stereotactic Breast Biopsy

Calcifications in breast microcysts frequently exhibit characteristic layering in 90-degree horizontal beam mammographic images. This observation is sufficiently predictive of a benign process that biopsy can be avoided. We report our experience with nine patients in whom stereotactic biopsy was attempted for clustered calcifications which failed to convincingly layer in true lateral magnification views. Two cases are described and illustrated. In all nine patients, layering of calcifications was more convincingly suggested on preliminary digital images prior to stereotactic biopsy. The effect of compression and dependent breast position may explain this observation. Calcification was sparse or absent in extracted cores yet diminished or disappeared in postbiopsy mammograms. Radiologists are alerted to these possible results when stereotactic biopsy of microcystic calcification is attempted.