A 45-year-old man presents with generalized lymphadenopathy and pruritus. Lymph node biopsy shows a nodular infiltrate of small cleaved cells (centrocytes) with CD10+, BCL6+, BCL2+, CD5−. The t(14;18) translocation is demonstrated. Grading of this lymphoma is based on which histologic parameter?
- A Ratio of centrocytes to centroblasts
- B Percentage of Ki-67 positive cells
- C Number of centroblasts per high-power field in neoplastic follicles ✓
- D Extent of diffuse growth pattern
Correct answer: C. Number of centroblasts per high-power field in neoplastic follicles
Explanation
Follicular lymphoma grading (WHO) is based on counting centroblasts per 40x high-power field (hpf) within neoplastic follicles: Grade 1 (0-5 centroblasts/hpf), Grade 2 (6-15/hpf), Grade 3C (>15/hpf with centrocytes present), and Grade 3B (>15/hpf with sheets of centroblasts). This grading system uses absolute centroblast count, not a ratio or Ki-67. Grade 3B is managed as DLBCL while grades 1-2 and 3C are managed as follicular lymphoma.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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