A 35-year-old woman has a breast mass. Core biopsy shows invasive carcinoma with E-cadherin loss on immunohistochemistry. This loss of E-cadherin is most characteristic of which histological type?
- A Invasive ductal carcinoma (NST)
- B Invasive lobular carcinoma ✓
- C Metaplastic carcinoma
- D Mucinous (colloid) carcinoma
Correct answer: B. Invasive lobular carcinoma
Explanation
Invasive lobular carcinoma is characterized by loss of E-cadherin (CDH1 gene mutation or methylation), which explains its distinctive single-file (Indian-file) infiltration pattern and discohesive cells. E-cadherin is a cell-cell adhesion molecule; its loss disrupts intercellular junctions. IHC showing absent E-cadherin is a key diagnostic marker distinguishing lobular from ductal carcinoma.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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