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 (<i>IRF4</i>) rearrangement (LBCL-<i>IRF4</i>-R) is one such entity. We present a case of classic low-grade follicular lymphoma with <i>IRF4</i> rearrangement in a 50-year-old male, demonstrating an unusual immunophenotypic and genetic profile reminiscent of LBCL-<i>IRF4</i>-R. Molecular analysis revealed mutations in <i>CREBBP</i>, <i>KMT2D</i>, <i>IRF4</i>, and <i>CARD11</i>, with previously unreported variants identified in <i>IRF4</i> and <i>CREBBP</i>. This case broadens the spectrum of B-cell lymphomas associated with <i>IRF4</i> rearrangement by demonstrating a small B-cell lymphoma with this genetic feature.