Histological pattern of benign breast disease as a risk factor for invasive breast cancer

Morphological criteria for histologic diagnosis of both typical and atypical breast epithelial hyperplasias have recently been thoroughly reviewed. Typical epithelial hyperplasia ranges from mild to florid and is characterized by a lack of cytologic atypia. Atypical hyperplasia (AH) is a borderline epithelial lesion between typical hyperplasia and carcinoma in situ. AH represents the most important histopathologic predictor of future breast cancer (BC) according to a case-control study we have recently carried out in a cohort of women previously treated for histologically confirmed benign breast disease (BBD). The use of histologically defined categories in order to predict BC risk depends on the utilization of strict and uniform diagnostic criteria that are currently far from being defined and widely accepted as shown in studies of inter-observer variability among pathologists. Further studies are needed to evaluate inter-observer reproducibility and to assess BC risk among women with different BBD types.