Question

A prostate biopsy reports a Gleason score of 4+4. Which ISUP/WHO Grade Group does this correspond to?

• A. Grade Group 1
• B. Grade Group 2
• C. Grade Group 3
• D. Grade Group 4

Hint:

Add the two patterns to get 8, then map 8 to the Grade Group.

Answer 1

The Correct Option is D

Step 1: Understand the Gleason grading system. The Gleason score for prostate adenocarcinoma is the sum of the primary (most predominant) pattern and the secondary pattern, each graded 1 to 5. A score is written as primary+secondary (e.g., 4+4 = 8).

Step 2: Recall the 2014 ISUP / WHO Grade Group mapping. To simplify prognostication, scores are grouped:
Grade Group 1 = Gleason ≤ 6 (3+3)
Grade Group 2 = Gleason 7 (3+4)
Grade Group 3 = Gleason 7 (4+3)
Grade Group 4 = Gleason 8 (4+4, 3+5, 5+3)
Grade Group 5 = Gleason 9-10 (4+5, 5+4, 5+5)

Step 3: Apply to 4+4. A Gleason 4+4 sums to 8 and falls into Grade Group 4.

Why the others are wrong: Grade Group 1 is 3+3, Group 2 is 3+4, and Group 3 is 4+3 - none match a score of 8 made of two pattern-4 components.

Key fact: Gleason 4+4 (score 8) = ISUP Grade Group 4.