Abstract
Diagnostic problems arise in interpreting breast aspiration cytology including the differentiation of several types of benign and malignant lesions. In aspiration cytology, cell pattern appearance reflects the histological image of the needle site, so the histological structure is presumed by observing patterns of the background, epithelial cells, and stromal tissues. It is important to understand these histological findings and differences between benign and malignant lesions to determine a histological diagnosis. Background findings are divided by origin into ductal and stromal. When the epithelial cell proliferation pattern is sheet-like, tubular, wedge-shaped, scattered, and has large clusters, compatible histological structures can be determined. Background findings are useful in considering histological structures as additional findings. Bipolar naked nuclei and myxomatous stroma are often seen in benign lesions. In low papillary ductal carcinoma in situ (DCIS) with scarce nuclear atypia, low papillary and crater-shaped structures are important in making a cytological diagnosis.
