Finding Missing Calcifications: How Deep to Cut?

Context.— Mammographic identification of microcalcifications may result in biopsy because many calcifications serve as markers for breast pathology. Absence of these calcifications in histologic sections may indicate that an area of concern has not been adequately sampled. Objective.— To determine the optimal cutting protocols to identify mammary calcifications. Design.— Our standard protocol for breast biopsies with suspected mircocalcifications is to cut 2 levels separated by 30 µm and if no microcalcifications are detected, an additional 10 levels are obtained. An electronic search of surgical pathology records was performed for cases with microcalcifications identified between January 1, 2022, and March 30, 2023. For each case, slides designated by the radiologist as containing microcalcifications were retrieved. The level at which microcalcifications were first detected was recorded. Results.— The search revealed 431 specimens meeting the search criteria, of which 415 contained microcalcifications. Probability of finding microcalcifications in the initial level was 0.629 and the probability of detecting microcalcifications in the first 4 levels was 0.905. Four hundred three of 415 microcalcifications documented by mammographic imaging (97%) were detected histologically in the first 6 levels. Conclusions.— A 6-level approach appears optimal for the detection of microcalcifications. This study may have implications for other specimen types where a strong suspicion exists for a pathologic lesion, but examination reveals no lesions in the initial sections. Protocols using 6-level-deep cuts may represent optimal sampling.