Abstract

We experienced a case of fine-needle aspiration(FNA) cytology of breast which showed atypical proliferative lesion. It was very difficult to differentiate this case from malignancy, because of hypercellular smear and many clusters composed of large, atypical ductal cells. However, it showed other features favoring benignancy, such as tendency of cellular cohesiveness, only slightly increased nucleus/cytoplasm ratio and most importantly presence of myoepithelial cells. It's histologic diagnosis was intraductal hyperplasia with atypia. This case indicates that all atypical breast FNA specimen should lead to the suggestion of surgical biopsy for avoiding over- or under-diagnosis.

• Keywords: Breast;Aspiration cytology;Atypical proliferative lesion;Intraductal hyperplasia with atypia