Abstract
BackgroundThe distinction between lobular neoplasia of the breast and ductal carcinoma in situ has important therapeutic implications. In some cases, it is very difficult to determine whether the morphology of the lesion is ductal or lobular. The aim of this study was to evaluate the value of E-cadherin and β-catenin expression through the immunophenotypical characterization of carcinoma in situ with mixed pattern (CISM).MethodsA total of 25 cases of CISM were analyzed considering cytology/mixed architecture (ductal and lobular), nuclear pleomorphism, loss of cell cohesion, and presence of comedonecrosis. The immunophenotype pattern was considered E-cadherin positive and β-catenin positive, or negative.ResultsNineteen (76%) cases presented a mixed cytology and / or architectural pattern, two (8%) presented nuclear pleomorphism, two (8%) presented mixed cytology and nuclear pleomorphism, and two (8%) presented comedonecrosis and nuclear pleomorphism. A complete positivity for E-cadherin and β-catenin was observed in 11 cases (44%). In one case, the lesion was negative for both markers and showed nuclear pleomorphis. Thirteen lesions showed negative staining in areas of lobular cytology and positive staining in cells presenting the ductal pattern.ConclusionsThe expression of E-cadherin and β-catenin, combined with cytological and architectural analysis, may highlight different immunophenotypes and improve classification of CISM.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1693384202970681
Highlights
The distinction between lobular neoplasia of the breast and ductal carcinoma in situ has important therapeutic implications
The aim of this study was to evaluate the expression of E-cadherin and β-catenin for the immunophenotypical characterization of carcinomas in situ with mixed pattern, and identify potential morphological patterns that could assist in the diagnosis of the different types of carcinoma in situ with mixed pattern (CISM) lesions
Immunohistochemistry for E-cadherin was performed in all 25 cases
Summary
The distinction between lobular neoplasia of the breast and ductal carcinoma in situ has important therapeutic implications. It is very difficult to determine whether the morphology of the lesion is ductal or lobular. According to the 2012 WHO classification of tumors of the breast, classic LCIS is diagnosed when more than half of the acini of a lobular unit are distended and distorted by a dyshesive proliferation of cells with small, uniform nuclei. Some in situ carcinomas present unusual cytological and / or architectural features, making it difficult to determine whether the proliferation is lobular or ductal. This group has been called carcinomas in situ with a mixed or indeterminate pattern (CISM) [2,3]
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