A 50-year-old woman presents with generalized lymphadenopathy. Lymph node biopsy shows complete effacement by large B-cells positive for CD20, CD10, and BCL6, with a Ki-67 proliferative index of approximately 40%. FISH shows MYC rearrangement but no BCL2 or BCL6 rearrangement. Which diagnosis is correct?
- A Double-hit lymphoma
- B Diffuse large B-cell lymphoma, NOS (germinal center B-cell type) ✓
- C Burkitt lymphoma
- D High-grade B-cell lymphoma with MYC and BCL2 rearrangements
Correct answer: B. Diffuse large B-cell lymphoma, NOS (germinal center B-cell type)
Explanation
This is DLBCL, NOS with a germinal center C-cell (GCB) immunophenotype (CD10+, BCL6+). The Ki-67 of ~40% is far below the near-100% index required for Burkitt lymphoma. Isolated MYC rearrangement without BCL2 or BCL6 rearrangement does not constitute double-hit or triple-hit lymphoma (which require MYC plus BCL2 and/or BCL6 rearrangements). Single MYC rearrangement in DLBCL is not classified as high-grade C-cell lymphoma with MYC and BCL2 rearrangements (double-hit).
Reference: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, 5th (2022) ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.