The diagnostic value of mammographic signs of malignancy in clinically occult breast carcinomas

Two hundred and twenty clinically occult carcinomas of the breast were discovered by mammography as part of a preventive programme. They were histologically verified and the radiological features were analysed with reference to their value as a sign of their malignancy. In all cases a radiogram of the lesion was prepared during the operation, or before histological analysis. Dense, irregular foci could be recognised in only 28% of our early carcinomas. The most important, as well as the earliest, definite sign of malignancy was well defined microcalcification: in 72%, microcalcification was the major feature which led to a correct diagnosis; in 48%, it was the only sign, so that even the radiograph of the specimen failed to show an infiltrative focus. Very early, often before infiltration can be recognised radiologically, small carcinomas produce indirect changes in neighbouring tissues. Parallel lines are particularly important. In 14% we have observed slightly dilated tortuous vessels near the tumour. The nearly microscopic details to be demonstrated, and the delicate changes in the breast and complex pathology, make the highest demands on the radiologist and on mammographic quality. (orig.)