Which histological feature best characterises medullary carcinoma of the breast?
- A Abundant extracellular mucin pools surrounding nests of tumour cells
- B Well-formed tubules invading in a single-file pattern
- C Syncytial sheets of pleomorphic cells with a dense lymphoplasmacytic infiltrate and pushing margins ✓
- D Concentric laminated psammoma bodies within ductal lumina
Correct answer: C. Syncytial sheets of pleomorphic cells with a dense lymphoplasmacytic infiltrate and pushing margins
Explanation
Medullary carcinoma shows syncytial growth of high-grade pleomorphic cells, a prominent lymphoplasmacytic infiltrate, circumscribed pushing borders, and absence of tubule formation. Despite its aggressive appearance it carries a relatively better prognosis than ordinary high-grade ductal carcinoma and is associated with BRCA1 germline mutations. Single-file infiltration describes invasive lobular carcinoma, extracellular mucin defines mucinous carcinoma, and psammoma bodies are a feature of papillary lesions rather than medullary carcinoma.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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