Cytological analysis of 11 cases with mucinous carcinoma of the breast in our hospital

Abstract

Objective : According to the new WHO classification, mucinous carcinoma of the breast is subdivided into types A and B as a pure type, but we often encounter mixed subtypes. There are only a few reports on cytological diagnostic studies on mucinous carcinoma based on the new WHO classification and comparison studies of the pure and mixed types of mucinous carcinoma.
Study Design : In this study, we investigated 11 cases of mucinous carcinoma of the breast, based on the new WHO classification.
Results : There were five cases of pure type including one type A tumor and four type B tumors and six cases of mixed type of type B mucinous carcinoma, of which contained neuroendocrine carcinoma and micropapillary carcinoma. The distinction between types A and B seems to be possible, based on the characteristics of cytoplasm and nuclei. However, the distinction between the type B component of both the pure and mixed type and neuroendocrine carcinoma was difficult because of the cytological similarity. The identification of invasive carcinoma and tumors not otherwise specified (NOS in two tumors was possible due to the presence of intracytoplasmic lumina. Additionally, the identification of micropapillary carcinoma was possible because of cytologic small clusters and the application of EMA immunocytochemistry.
Conclusion : It is important to identify the components in mucinous carcinoma, with the exception of neuroendocrine carcinoma in the mixed type, as some reports have shown that the prognosis of the mixed type is worse than the pure type.