Invasive lobular carcinoma. Mammographic pattern.

A retrospective study was done on 107 histologically proven cases of invasive lobular carcinoma which represent about 11.5% of the total of 934 cases of cancer of the breast. Age, breast parenchyma pattern and morphology, and radiological signs of malignancy were tabulated and correlated with the same data in ductal carcinoma. The number of false negative cases was almost twice as high as in ductal carcinoma type (19% versus 10%). In the majority of cases the patients presented a glandular or dense type of parenchyma pattern, which reduced the internal visibility. Besides spiculated masses, relatively subtle signs of malignancy, as asymmetric density and architectural distortion were relatively more frequently represented than in the ductal type of breast carcinoma. No clear-cut radiological criteria could be found pointing toward the underlying histology. Discreet clinical signs in younger patients with glandular or dense breast should alert the radiologist to the possible presence of this type of carcinoma. Due attention should be warranted to these less conspicuous signs of malignancy such as asymmetric density and architectural distortion.