According to the Nottingham Histological Grade (Bloom–Richardson) for breast carcinoma, which three parameters are assessed, each scored 1–3?

Explanation

## Nottingham Histological Grade (Bloom–Richardson) — Breast Cancer Grading **Key Point:** The Bloom–Richardson system is the gold standard for grading invasive breast carcinoma and is based on **three histomorphological parameters**, each scored 1–3, for a total score of 3–9. ### The Three Scoring Parameters | Parameter | Score 1 | Score 2 | Score 3 | |-----------|---------|---------|----------| | **Tubule Formation** | >75% tubules | 10–75% tubules | <10% tubules | | **Nuclear Pleomorphism** | Small, uniform nuclei | Intermediate variation | Large, highly irregular nuclei | | **Mitotic Rate** | Low (0–9 per 10 HPF) | Intermediate (10–19 per 10 HPF) | High (≥20 per 10 HPF) | ### Grade Assignment from Total Score - **Grade I (Well-differentiated):** Score 3–5 → Better prognosis - **Grade II (Moderately differentiated):** Score 6–7 → Intermediate prognosis - **Grade III (Poorly differentiated):** Score 8–9 → Worse prognosis **High-Yield:** This grading system is **independent of TNM staging** and is mandatory for all invasive breast cancers. Grade III tumors have significantly worse 5-year survival compared to Grade I. **Mnemonic:** **TNM** = Tumor extent; **Bloom–Richardson** = **TuNM** (Tubule formation, Nuclear pleomorphism, Mitotic rate) — the three histological features. **Clinical Pearl:** Tubule formation reflects tumor differentiation; nuclear pleomorphism reflects genetic instability; mitotic rate reflects proliferation — together they capture the tumor's biological behavior. [cite:Robbins 10e Ch 24]