A 64-year-old man presents with generalised painless lymphadenopathy and anaemia. Node biopsy shows a monomorphic population of small to medium-sized lymphocytes with irregular nuclei arranged in a diffuse and vaguely nodular pattern. Immunohistochemistry shows strong nuclear staining for cyclin D1. The pathognomonic genetic alteration is:
- A t(14;18) causing BCL2 overexpression
- B t(11;14) fusing CCND1 with the IgH gene promoter-enhancer ✓
- C t(8;14) causing MYC deregulation
- D del(13q) as the sole cytogenetic abnormality
Correct answer: B. t(11;14) fusing CCND1 with the IgH gene promoter-enhancer
Explanation
Mantle cell lymphoma is defined by t(11;14), which brings the CCND1 gene encoding cyclin D1 under IgH enhancer control, causing constitutive cyclin D1 expression and unchecked G1 to S transition; nuclear cyclin D1 staining is diagnostic. BCL2 rearrangement belongs to follicular lymphoma, MYC translocation to Burkitt lymphoma, and isolated del(13q) is a favourable-risk lesion in CLL, none of which produce cyclin D1 overexpression.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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