Examination of breast needle core biopsy specimens performed for screen-detected microcalcification

To establish the number of histological levels necessary for the evaluation of breast needle core biopsy (NCB) specimens taken from areas of mammographic calcification in patients presenting via the UK National Health Service Breast Screening Programme.

Retrospective review of a series of breast NCB specimens initially examined routinely at nine levels. The presence of calcification within the histological sections in each of three sets of levels (levels 1-3, 4-6 and 7-9) and the (cumulative) diagnostic B category that would have pertained after each were assessed.

Accurate diagnostic classification was possible after examination of three levels in 89% cases. Examination of a further three levels permitted accurate diagnosis in a further eight cases (total 97% cases). In only three cases were nine levels necessary for accurate classification. In only a single case (1%) was it likely that routine examination of six levels could have led to significant misclassification. In a significant group of patients (18%), nine levels were considered to provide additional useful information, although this information did not alter the diagnosis.

NCBs for screen-detected mammographic calcification should be routinely examined at six levels. Further levels may be needed in occasional cases to identify more conclusively the associated pathological abnormality. Further levels may be of particular value when assessing atypical intraductal proliferative epithelial lesions.