Atypical Ductal Lesion in the Breast: Review

Atypical ductal lesions of the breast are considered mainly “Atypical ductal hyperplasia (ADH)” ADH is defined as intraductal feature of architectural atypia [1]. However, diagnosis of ADH is challenging, because the interpretation of diagnosing ADH is different and vary between diagnostic pathologists. Goi S [2] advocated two pattern theory in the breast [2]. First, true borderline malignancy lesions are existed in the breast. Second, true borderline malignancy lesions are not existed, because borderline malignancy lesions which was thought at a glance are not true borderline lesions but pathologists cannot divide between malignant and benign because of their incapable. Goi S. thought that the latter theory was appropriate. Furthermore, he also thought that benign and malignant should be rigidly separated, and the most important thing is to reduce overdiagnosis or underdiagnosis. However, our recent study indicates the existence of the true borderline lesion. After paragraph, I will write this matter in detail. In addition, ADH is not clearly understood whether borderline malignancy or not, and that is still wrapped mysteriously.