Paper II — 2025 March (Supplementary (SAY)) (2019 Scheme) — Qxvi
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Paper II
2025 March (Supplementary (SAY)) (2019 Scheme) · 100 marks · 180 min
Question
Microscopy of this lesion will show all EXCEPT
a) Tumour cells forming tubules and irregular sheets
b) Nuclear pleomorphism and numerous mitosis
c) Malignant cells separated by dense fibrous stroma
d) Ducts lined by epithelial and myoepithelial cells and stroma proliferating circumferentially
Qxvi1 marksMCQs
Answer
Correct answer: d) Ducts lined by epithelial and myoepithelial cells and stroma proliferating circumferentially
This clinical picture (58-year-old female, solitary, ill-defined, firm-to-hard breast mass with palpable axillary nodes) is highly suspicious for invasive breast carcinoma (invasive ductal carcinoma, no special type). Option d describes a retained, intact two-cell-layer (epithelial + myoepithelial) ductal structure with circumferential stromal proliferation — this is the pattern of a benign fibroepithelial lesion (fibroadenoma/phyllodes tumour), not invasive carcinoma. Invasive carcinoma is defined by loss of the myoepithelial cell layer (breach of the basement membrane) as tumour cells invade the stroma. The other three features (tumour cells forming tubules/irregular sheets, nuclear pleomorphism with numerous mitoses, and malignant cells set within a dense desmoplastic fibrous stroma) are all genuine microscopic features of invasive ductal carcinoma.
