Contemporary Issues in Immunohistochemistry Utilization in Breast Pathology

Immunohistochemistry is utilized in all facets of diagnostic breast pathology. Recognition of aberrant E-cadherin expression in invasive lobular carcinoma and lobular carcinoma avoids misinterpretation. A context-focused battery of stains will most successfully identify microinvasion. Based on current publications, the most sensitive single marker for confirmation of metastatic breast cancer is GATA3, while in the breast proper, TRPS1 demonstrates slight superiority over GATA3. TRPS1 and SOX10 are the most specific marker combination for confirmation of primary and metastatic triple negative breast cancer. Knowledge of variations in immunohistochemical staining patterns in Paget disease can prevent misdiagnosis.