The most common breast lesions that result in equivocal diagnosis and defined as ‘'gray zone'' in fine needle aspiration cytology are fibroadenomas and low grade ductal carcinomas. In case of equivocal fine needle aspiration cytology, a multidisciplinary approach is required and usually the case necessitates histopathological confirmation. In order to decrease number of operational biopsies in benign lesions, the rate of equivocal cytological diagnosis should be reduced. Current study aims to determine if nuclear morphometric analysis in cases with equivocal cytology aids for further categorization as benign or malign.

In our study, 45 equivocal breast cytology specimens have been analyzed retrospectively. All cases had histopathologic diagnosis. We utilized computerized image analysis software to obtain mean nuclear diameter, mean nuclear perimeter and mean nuclear area from measuring 30-50 randomly selected nuclei in a microscope with 40x objectives. Nuclear morphometric values were compared with histopathological diagnosis. Of 45 cases, 12 were benign. In benign group, mean nuclear diameter was 9,9 µm; mean nuclear perimeter was 29,26 µm and mean nuclear area was 68,19 µm². In malignant group, mean nuclear diameter was 10µm; mean nuclear perimeter was 30,28 µm and mean nuclear area was 70,03 µm². No statistical differences in mean nuclear diameter, perimeter and area were found between malignant and benign groups with nonparametric tests.

Our results showed that lesions leading to equivocal diagnosis (such as fibradenomas and low grade invasive ductal carcinomas) display similar nuclear morphometric values. Nuclear morphometric analysis based on image analysis did not help to distinguish the borderline lesion for further specification.