Statistical Analysis of the Diagnostic Accuracy of Morphological Features in the Cytological Diagnosis of Proliferative Breast Lesions

Cytological features of the various proliferative breast lesions have been described by numerous authors. The aim of this study was to evaluate the usefulness of these criteria in diagnosing epithelial hyperplasia with atypia (EHA), papillary lesions (PLs) and radial scar/complex sclerosing lesions (RS/CSLs) by fine needle aspiration biopsy (FNAB). EHA is a cytological diagnosis that raises a histological differential diagnosis of florid epithelial hyperplasia, atypical ductal hypeplasia and low-grade ductal carcinoma in situ. Papillary lesions in this study refer to intraduct papillomas of varying types including complex intraduct papillary lesions (CIPLs). This study comprised both retrospective and prospective components. In the retrospective component, 77 cases found to be suitable for the study, were reviewed. They comprised 13 cases of EHA, 52 cases of PLs and 12 cases of RS/CSL. Cytological criteria were extracted from the literature, together with in-house criteria, which have been developed and used at the St. Vincent’s Hospital, Sydney. Slides were reviewed and scored against these criteria. The results were analysed statistically to test if there was a significant association between the cytological criteria and the histological outcomes. As the number of cases for the groups of EHA and RS/CSL were small compared to PLs, they were grouped together in the statistical analysis. One of the most significant findings was that the presence of stellate or meshwork stromal fragments is highly predictive of a PL. Papillary fragments were found infrequently and were of limited use in making the diagnosis of a PL, which is in contradiction to much of the literature. The prospective part of the study aimed to test the sensitivity, specificity and positive predictive value of the criteria evaluated in the retrospective study in the diagnosis of PLs. Of the 1154 cases collected, 74 were suitable for slide review and scoring. It was again found that meshwork stromal fragments occurred most frequently in PLs followed by stellate stromal fragments, whereas papillary fragments had the lowest