Low‐grade follicular lymphoma with interferon regulatory factor‐4 rearrangement: Expanding the spectrum of interferon regulatory factor‐4‐rearranged lymphomas

In recent years, the recognition of distinct lymphoma entities has expanded with advancements in molecular characterization. Large B‐cell Lymphoma with interferon regulatory factor‐4 (IRF4) rearrangement (LBCL‐IRF4‐R) is one such entity. We present a case of classic low‐grade follicular lymphoma with IRF4 rearrangement in a 50‐year‐old male, demonstrating an unusual immunophenotypic and genetic profile reminiscent of LBCL‐IRF4‐R. Molecular analysis revealed mutations in CREBBP, KMT2D, IRF4, and CARD11, with previously unreported variants identified in IRF4 and CREBBP. This case broadens the spectrum of B‐cell lymphomas associated with IRF4 rearrangement by demonstrating a small B‐cell lymphoma with this genetic feature.