Grading Breast Cancer: Modified Bloom Richardso Grading Made simple

Breast Cancer Grading

Modified Bloom-Richardson Grading System

How it works:

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Criteria for Assessing Tumor Grade

To grade a tumor, three histologic features are evaluated: Tubule formation, Nuclear pleomorphism and Mitotic count

Point System

Each category is assigned a score 1, 2 or 3 points based on the histologic findings within the tumor

Tumor Grading

The overall tumor score (total points) designates the tumor as either Grade 1 (low grade), 2 (intermediate grade) or 3 (high grade).

Criteria for Assessing Tumor Grade

To grade a tumor, three histologic features are evaluated: Tubule formation, Nuclear pleomorphism and Mitotic count

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Point-Scoring System

The tumor should be graded based on the representative portion of tumor (not the least differentiated part). Three factors are assessed when determining the grade:

Tubule formation: How much of the tumor tissue has normal breast (milk) duct structures.
- Tubules must have clear central lumina to be counted
Nuclear grade: An evaluation of the size and shape of the nucleus in the tumor cells.
- Evaluate the “ugliest” area of tumor for nuclear pleomorphism
Mitotic rate: How many dividing cells are present, which is a measure of how fast the tumor cells are growing and dividing.
- Assess mitotic count in the most active part of the tumor.
- You should count at periphery of tumor.
- Need to assess 10 high powered fields, but they don’t have to have 10 contiguous fields