mammary carcinoma grading
Thursday 29 August 2013
breast cancer grading
Nottingham Histologic Score ("Elston Grade")
It is the Elston-Ellis modification of Scarff-Bloom-Richardson grading system.
In this scoring system, there are three factors that the pathologists take into consideration:
score a: the amount of gland formation ("differentiation" or how well the tumor cells try to recreate normal glands)
score b: the nuclear features ("pleomorphism" or how "ugly" the tumor cells look)
score c: the mitotic activity (how much the tumor cells are dividing)
Each of these features is scored from 1-3, and then each score is added to give a final total score ranging from 3-9. The final total score is used to determine the grade in the following way:
Grade 1: tumors have a score of 3-5
Grade 2: tumors have a score of 6-7
Grade 3: tumors have a score of 8-9
Detailed Criteria used in Histologic Grade
Score a: Glandular (Acinar)/Tubular Differentiation
Score 1: >75% of tumor area forming glandular/tubular structures
Score 2: 10% to 75% of tumor area forming glandular/tubular structures
Score 3: < 10% of tumor area forming glandular/tubular structures
Score b: Nuclear Pleomorphism
Score 1: Nuclei small with little increase in size in comparison with normal breast epithelial cells, regular outlines, uniform nuclear chromatin, little variation in size.
Score 2: Cells larger than normal with open vesicular nuclei, visible nucleoli, and moderate variability in both size and shape.
Score 3: Vesicular nuclei, often with prominent nucleoli, exhibiting marked variation in size and shape, occasionally with very large and bizarre forms.
Score c: Mitotic Count
The mitotic count score criteria vary depending on the field diameter of the microscope used by the pathologist. The pathologist will count how many mitotic figures are seen in 10 high power fields. Using a high power field diameter of 0.50 mm, the criteria is as follows:
Score 1: less than or equal to 7 mitoses per 10 high power fields
Score 2: 8-14 mitoses per 10 high power fields
Score 3: equal to or greater than 15 mitoses per 10 high power fields
Grade 1: total scores of 3, 4, or 5
Grade 2: total scores of 6 or 7
Grade 3: total scores of 8 or 9