Large B-cell lymphoma with IRF4 rearrangement: a special tonsillar lymphoma in children

Abstract Objective To identify the clinicopathological features and prognosis of large B-cell lymphoma(LBCL) with interferon regulation factor 4 (IRF4) rearrangement. Methods We retrospectively analyzed the medical records of four patients from Children’s Hospital of Fudan University diagnosed with LBCL with IRF4 rearrangement during Sep. 2014 to Oct. 2018, and performed a literature review. Results Four patients had an average age of 5.7 years. The median duration from presentation to final diagnosis was 25.7 days. All 4 patients were admitted to the hospital due to severe snoring with no causes. The patients showed enlarged lymph nodes in the neck without tenderness. All 4 cases presented as localized disease (St-jude stage II). Lactate dehydrogenase (LDH) and serum albumin were all in the normal range. Morphology showed that normal lymphoid follicles were diffusely invaded by consistent, medium-sized large cells with obvious nucleoli. CD20, CD79α, PAX5, CD10 and BCL6 were diffusely positive. Neoplastic cells were also strongly positive for MUM1 and Ki-67. IRF4 gene rearrangement was detected as positive by IRF4 dual-color break-apart probe. Four patients underwent routine chemotherapy post bilateral tonsillectomy operation. Three achieved complete remission (CR) while the newly diagnosed one is during the second course of chemotherapy. Conclusions Tonsillar LBCL with IRF4 rearrangement in children presents distinct clinicopathologic and molecular genetic features, and it usually has a favorable outcome.