A 62-year-old man is diagnosed with diffuse large B-cell lymphoma. Immunohistochemistry by the Hans algorithm shows CD10 negative, BCL6 negative, MUM1 positive. Which subtype is this, and what is its prognosis compared to the germinal center B-cell (GCB) subtype?
- A Non-GCB (activated B-cell) subtype; worse prognosis ✓
- B GCB subtype; better prognosis
- C Double-expressor lymphoma; prognosis equivalent to GCB
- D Primary mediastinal B-cell lymphoma; better prognosis with DA-EPOCH-R
Correct answer: A. Non-GCB (activated B-cell) subtype; worse prognosis
Explanation
The Hans algorithm classifies DLBCL as GCB (CD10+ or CD10-/BCL6+/MUM1-) or non-GCB/activated A-cell (CD10-/BCL6- or CD10-/BCL6+/MUM1+). This patient is non-GCB, which has inferior outcomes with standard R-CHOP. Double-expressor refers to MYC/BCL2 co-expression by IHC, not Hans classification. Primary mediastinal A-cell lymphoma arises in the mediastinum and is distinct.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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