Large B-Cell Lymphoma With IRF4 Rearrangement: From Theory to Practice

Interferon regulatory factor 4 (IRF4) rearrangement is a common cytogenetic anomaly reported in various neoplastic lymphoproliferative disorders. IRF4 is a gene located on chromosome 6 that encodes for the IRF4 protein belonging to the IRF family of transcription factors. Large B-cell lymphoma with IRF4 rearrangement constitutes a novel provisional entity included in the classification of lymphoid tissue recently proposed by the World Health Organization in its fourth revised edition. This rare entity, with a specific clinical presentation, is defined by the presence of a rearrangement of the IRF4 gene. We report a rare case of a 19-year-old female patient presenting with a large B-cell lymphoma with IRF4 rearrangement located in the right tonsil, with characteristic histologic appearance and the phenotype of neoplastic cells. The presence of an IGH-IRF4 rearrangement was also confirmed, using a fluorescence in situ hybridization analysis with 2 successive hybridizations on the same slide. Patient was treated with 6 cycles of R-CHOP with no evidence of recurrence.