Histopathologic and Immunohistochemical Analysis of PureType Mucinous Carcinomas of Breast

Abstract

Background: The mucinous carcinomas are known to be well- demarcated border with less aggressive biologic behavior and good prognosis. The aim of this study is to investigate the histopathologic findings of mucinous carcinomas including tumor border, size, associated lesion, and immunohistochemical characteristics. Method: A pathological analysis of 45 cases of pure form of mucinous carcinoma was carried out. The histologic review by light microscopy had done and followed by immunohistochemical studies. Results: The mean age of patients was 44.8 years old. The tumor borders of mucinous carcinoma were classified into pushing border in 11 cases (24.4%), partly infiltrative border in 18 cases (40.0%), and irregular infiltrative border in 16 cases (35.6%). The pure type of mucinous carcinomas had more commonly infiltrative in tumor borders and irregular shape as other malignant tumors. The mucinous carcinomas with infiltrative border were often associated with lymph node metastasis, younger ages, and association of micropapillary carcinoma in adjacent areas. The associated lesions were micropapillary carcinomas in 5 cases (11.1%), and tubular carcinoma in 1 case (2.2%). Ductal carcinomas in situ (DCIS) were present in 28 (62.2%). In immunohistochemical study, expression of galectin-3 in tumor with DCIS was lower than in the tumor with no DCIS. Expression of synaptophysin was associated with ductal carcinoma in situ, but no difference in grade of ductal carcinoma in situ. Conclusion: The pure type of mucinous carcinomas has more commonly infiltrative border and irregular shape than well demarcated pushing border. These mucinous carcinomas are often associated with lymph node metastasis, association with micropapillary carcinoma, and young age. The mucinous carcinomas with infiltrative border may have more aggressive behavior than that to be previously known. So the mucinous tumors with infiltrative border, especially associated with micropapillary carcinoma, is needed to take notice of treatment or follow up.