A study of surgically removed specimens of breast, with special reference to sclerosing adenosis.

It is now generally accepted that carcinoma of the breast is not restricted to the middle-aged or elderly woman and that a mass in the breast in a woman of any age must be regarded as malignant until it is proved to be benign. This recognition, which has recently been re-emphasized elsewhere (Sandison, 1955), has led to a considerable increase in the demand by surgeons for immediate examination of frozen sections in the theatre in cases of a mass in the breast of younger women. In many instances such examinations will quickly show whether or not a lesion is malignant. The appearance known as sclerosing or fibrosing adenosis may present, especially to the less experienced pathologist, a puzzling picture, and one which may erroneously be diagnosed as carcinoma. In sections prepared by the paraffin embedding method the appearance is less likely to be misinterpreted as carcinoma, but even here difficulty in interpretation has been known. This difficulty is especially important, since sclerosing adenosis is most characteristically seen in younger women in whom mastectomy leads to greater mental distress than in older women. It therefore seems worth while to indicate the frequency with which this picture of sclerosing adenosis has been encountered in the examination of surgically removed breasts or portions of breasts in a fiveyear period in this laboratory during which just over 1,000 breast specimens were received. The salient features of sclerosing adenosis may be outlined as follows. It produces a firm, mobile nodular or discoid lump in the breast, most frequently in younger women, and is thought to be due possibly to some temporary hormonal imbalance (Dawson, 1954). The naked-eye appearance is that of a greyish-white nodular mass with hyperplastic lobular areas sometimes associated with cysts. Histological examination confirms the lobular nature of the lesion-a most important diagnostic point. The cytological character varies