[An analysis of 153 areas of microcalcification of malignant origin: the "triangle principle" (author's transl)].

The forms and outlines of 153 clustered microcalcifications in 114 patients with histologically proven intraduct carcinomas were analysed. Seven groups could be defined; of these, a triangle principle"). The smaller groups tended to have straight margins, but the larger groups often showed wavy contours and at least one indentation at the base ("Swallow-tail phenomenon"). At the same time, the larger groups show circumscribed areas free of microcalcification, which correspond to interductal fat deposition. All these radiological appearances can be related to the anatomical structures of the lactiferous ducts.