E-cadherin Expression in Distinguishing Ductal and Lobular Carcinomas of the Breast

ABSTRACT

BACKGROUND: Most breast carcinomas are easily categorized as ductal or lobular. However, in some cases the distinction can be difficult since some tumors may have intermediate features of these two. Prior studies suggest that E-cadherin is useful to classify tumors as ductal or lobular, as it is lost in lobular but not in ductal carcinomas. METHODS: We studied the histologic features and E-cadherin expression by immunohistochemistry in 57 cases of breast carcinomas, which were divided into three groups based on histology. Group 1 included 4 cases of infiltrating lobular carcinoma (IFL) and 1 case of lobular carcinoma in situ (LCIS) (n=5). Group 2 included infiltrating ductal carcinoma (IFD) with some features of IFL (n=48). Group 3 included a solid type of intraductal carcinoma (DCIS) (n=4). E-cadherin staining was scored as negative or positive. RESULTS: All 5 cases from group 1 were E-cadherin negative, and all 4 DCIS cases were positive. Only 2 (0.04%) of the 48 cases from group 2 were E-cadherin negative. CONCLUSIONS: Our findings suggest that the majority of cases with morphologically IFD with some IFL features are ductal. E-cadherin immunostaining is of value in helping to characterize breast carcinomas with indeterminate morphologic features.