Different types of microcalcifications observed in breast pathology. Correlations with histopathological diagnosis and radiological examination of operative specimens.

Microcalcifications taken from 50 systematized mammary excisions were submitted to light microscopic and scanning electron microscope analysis. Microprobe and x-ray diffraction analyses were also performed. Two main types were observed: Type I microcalcifications composed of weddellite crystals. They were observed in benign breast lesions only (11 cases out of 21) or, in lobular carcinomas in situ (L.C.I.S.) of the breast (5 cases out of 6). They were not seen in 3 cases of intraductal carcinoma (I.D.C.) nor in infiltrating (I.C.) carcinomas (20 cases). Type II microcalcifications, non-cristalline in nature, composed of calcium, phosphate, hydroxyapatite or of phosphorus and calcium associated with other elements, were observed in benign lesions (10 cases out of 21) and in all cases of infiltrating carcinomas. The microcalcifications observed on mammography were also found on the radiographs of systematised mammary excisions from the lesion or from its immediate vicinity, but only when using the appropriate technique. Microcalcifications are therefore an excellent marker of breast lesions but they cannot be simply divided into "benign" or "malignant" types. Nevertheless, the presence of a visible crystalline structure on the radiograph of the specimen argues in favour of a benign breast lesion or of a lobular carcinoma in situ.