Granulomatous mastitis: the histological differentials.

BACKGROUND: The management of granulomatous mastitis depends on the causative factor, and accurate diagnosis in distinguishing between idiopathic granulomatous mastitis (IGM) and tuberculous mastitis (TBM) is indispensable. This is particularly problematic in the cases of granulomatous mastitis in which the microbiological studies are negative. In this study, in a large cohort, the histological features for IGM and TBM were compared. METHODS: The histopathology files from the two participating hospitals were searched for cases of granulomatous inflammation of the breast over an 8-year period. The parameters assessed included age of patient, lesional size, systemic and local symptoms, and histological findings of inflammatory cells, granulomas, necrosis, multinucleated giant cells, fibrosis and calcifications. RESULTS: 29 cases of IGM and 33 cases of TBM were included in this study. A significant difference was seen between the two groups with regard to patient age (t=2.52, p<0.05) and lesional size (t=-5.56, p<0.01). TBM occurred in a significantly younger population, and demonstrated larger lesional sizes than IGM. There was no difference between the number of cases showing mass, local and systemic symptoms. Comparing the different histological features, the TBM group showed significantly more fibrosis, eosinophils and necrosis, whereas the IGM group showed significantly more plasma cells. Taking all the cases together as one group to evaluate the relationship between the histological parameters, there was significant positive correlation between eosinophils and fibrosis (r(s)=0.39, p<0.01), and negative correlation between vague and well-formed granulomas (r(s)=-0.38, p<0.01). CONCLUSION: TBM was more likely to occur in younger patients, with a larger clinical mass at presentation. Histologically, TBM tends to show more eosinophils and necrosis, and IGM is associated with more plasma cells. The characteristics of the granulomas and giant cells were not distinguishing features.

Atypia in fine needle aspirates of breast lesions.

BACKGROUND: The atypical category is controversial in fine needle aspiration cytology (FNAC) of the breast; most are benign, but a significant number are malignant. To date, no morphological criterion has been found to be consistent in predicting malignancy. AIMS: To evaluate specific cytological parameters and assess their usefulness in predicting histological outcome in a cohort of atypical breast FNAC, in order to establish a set of objective criteria in defining 'high risk' atypical breast FNAC. METHODS: A retrospective review of 98 cases of atypical breast FNAC with histological correlation was undertaken. The cytological preparations were evaluated for cellularity, percentage of epithelial cell cluster and single epithelial cells, nuclear atypia, nucleus:cytoplasm ratio, percentage of bipolar nuclei, and the presence of stromal fragments, histiocytes and necrosis. RESULTS: 66 of 98 cases (67.35%) showed benign histology and 32 cases (32.65%) showed malignant histology. Compared with the malignant group, the benign group had significantly lower patient age (p=0.05), higher bipolar nuclei (p<0.0001), less degree of nuclear pleomorphism (p<0.0001), lower nucleus:cytoplasm ratio (p<0.0001), lower cellularity (p=0.05) and less necrosis (p<0.001). There was no difference in the percentage of epithelial clusters and single cells, or the presence of stromal fragments and histiocytes. CONCLUSIONS: The presence of nuclear pleomorphism, high nucleus:cytoplasm ratio, epithelial cell atypia, low number of bipolar nuclei and necrosis are useful parameters to predict malignancy in atypical FNAC of the breast. Assessment of these factors in atypical FNAC may be helpful in predicting cancer risk and subsequent management decision making.