Which histological feature is characteristic of medullary carcinoma of the breast and distinguishes it from invasive ductal carcinoma, not otherwise specified?
- A Dense lymphoplasmacytic infiltrate with pushing borders and high-grade nuclei ✓
- B Abundant extracellular mucin pools
- C Single-file (Indian file) pattern of infiltrating cells
- D Extensive ductal carcinoma in situ component exceeding 25 percent
Correct answer: A. Dense lymphoplasmacytic infiltrate with pushing borders and high-grade nuclei
Explanation
Medullary carcinoma shows a dense lymphoplasmacytic infiltrate, well-circumscribed pushing borders, syncytial growth pattern, and high-grade nuclei. Despite high-grade histology, it has a better prognosis than typical invasive ductal carcinoma. Mucinous pools characterize colloid carcinoma. Single-file pattern is seen in invasive lobular carcinoma. Extensive DCIS is seen in comedo-type DCIS, not medullary carcinoma.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.