In situ lobular proliferations of the breast

Abstract Lobular proliferations of the breast include a number of lesions with varying cytological and histological features and clinical significance. Here, we provide an update on the current state of knowledge of classical lobular neoplasia (atypical lobular hyperplasia and lobular carcinoma in situ) and variants (pleomorphic and LCIS with necrosis) with emphasis on the morphological features, histological mimics, molecular profile and clinical relevance. The management of those lesions on both core biopsy and surgical specimens is also discussed.