A 55-year-old woman presents with constitutional symptoms, cervical and inguinal lymphadenopathy, and splenomegaly. PET-CT shows diffuse nodal disease. Biopsy shows a neoplasm positive for CD20, CD10, BCL-2, and BCL-6, with a t(14;18) translocation and a Ki-67 of 30%. The diagnosis is:
- A Diffuse large B-cell lymphoma (DLBCL)
- B Mantle cell lymphoma
- C Follicular lymphoma (grade 1–2) ✓
- D Marginal zone lymphoma
Correct answer: C. Follicular lymphoma (grade 1–2)
Explanation
Follicular lymphoma is defined by CD20+, CD10+, BCL-2+, BCL-6+ immunophenotype and the hallmark t(14;18)(q32;q21) translocation causing BCL-2 overexpression. A Ki-67 of 30% and the nodular/follicular architecture at low grade distinguish it from DLBCL (Ki-67 >40%, diffuse pattern). Mantle cell lymphoma has t(11;14) and CD5+/cyclin D1+, while marginal zone lymphoma lacks BCL-2 translocation.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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