[Cytopathology of the breast--benign and malignant neoplastic conditions]

Breast cancer is one of the most common malignancies in women and the incidence has been increasing. Cytology plays a very important role not only in the diagnosis of breast lesions, but also in keeping the benign-to-malignant biopsy ratio low, so that unnecessary surgery is not performed. A fundamental feature of a benign aspirate is the presence of a dual population of ductal epithelial cells (variable within limits, but cohesive and orderly) and myoepithelial cells (naked, bipolar nuclei). Several cytologic features must be assessed to make the diagnosis of malignancy, including high cellularity, cell dissociation, large nuclear and cell size, cell pleomorphism, intracytoplasmic lumens (containing mucin), irregular nuclear margin, coarse chromatinic pattern, prominent nucleoli, and the presence of abnormal mitoses. Other criteria of lesser importance include necrosis, absence of myoepithelial cells and intranuclear inclusions. However, breast carcinomas do not always show every feature of malignancy. The well-differentiated or low-grade carcinomas are often difficult to differentiate from benign cells. It may be helpful to consider the clinical and radiological findings. We reported here, typical neoplastic lesions of the breast by correlating cytological with histopathological features.