Circumscribed intraductal carcinoma of the breast

In a retrospective evaluation of 350 cases of proved intraductal carcinoma detected over a 3-year period, 13 had mammographic features similar to those of benign tumors. The carcinomas were sharply circumscribed, round or oval lesions that contained microcalcifications. These calcifications were smaller and more likely to be asymmetrically located within the nodule than those of the fibroadenomas that they mimicked. While the carcinomas appeared circumscribed on mammograms, microinvasion of surrounding tissue was proved histologically in five of 13 cases, and in another case biopsy revealed metastasis to an axillary lymph node. Although these carcinomas are relatively rare, mammographic detection is important as none were palpable at the time of diagnosis.