A 62-year-old man presents with generalized lymphadenopathy and multiple polypoid lesions throughout the colon on colonoscopy. Lymph node biopsy shows a monomorphic population of small to medium lymphoid cells. Immunohistochemistry shows strong nuclear positivity for cyclin D1. What is the underlying genetic lesion?
- A t(11;14)(q13;q32) with CCND1-IGH fusion ✓
- B t(14;18)(q32;q21) with BCL2-IGH fusion
- C Trisomy 12 with NOTCH1 mutation
- D del(11q) with ATM loss
Correct answer: A. t(11;14)(q13;q32) with CCND1-IGH fusion
Explanation
This is mantle cell lymphoma presenting as multiple lymphomatous polyposis of the gastrointestinal tract. The defining lesion is t(11;14), placing CCND1 (cyclin D1) under the immunoglobulin heavy chain promoter, giving the characteristic nuclear cyclin D1 staining. SOX11 supports diagnosis in cyclin-negative cases. CLL shares CD5 expression but is CD23 positive and lacks cyclin D1 overexpression, which excludes trisomy 12.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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