Clustering of breast microcalcifications: Revisited

AIM: To verify the diagnostic value of the traditional definition of 'clust ering' of microcalcifications (more than five in the area of 1 cm(2) or 1 c m(3)) on mammography in the differential diagnosis of benign and malignant breast disease. METHODS AND MATERIALS: Three radiologists without knowledge of the final pa thology retrospectively counted the number of microcalcifications per 0.25c m(2) (0.5 x 0.5cm) unit area on mammography in 57 pathologically proven non -palpable lesions including 26 cancers and 31 benign diseases. Pleomorphism of the microcalcifications, associated architectural distortion or mass or increased density and distribution of microcalcifications were also evalua ted. RESULTS: The mean numbers of microcalcifications per 0.25 cm(2) were 16.4 i n malignant and 16.7 in benign diseases (no statistically significant diffe rence between the two groups). Pleomorphism of the microcalcifications, ass ociated architectural distortion or mass or increased density were, however , important determining parameters, Clustering was more frequently observed in benign diseases. CONCLUSION: In this study, the mean number of microcalcifications per unit area is much larger than the traditional definition of 'clustering' and clu stering itself is not effective in the differential diagnosis of benign and malignant breast lesions. Imaging features other than numbers of calcifica tion per unit area are more important in assessing the significance of mamm ographic clustered microcalcifications. (C) 2000 The Royal College of Radio logists.