Large B-cell lymphoma with IRF4 rearrangement-Fine needle biopsy-Report of a case with an atypical presentation.

We describe a case of a 17-year-old girl with a mediastinal large B-cell lymphoma with IRF4 rearrangement (LBCL-IRF4r) with an atypical clinical presentation in an unusual location, diagnosed by fine needle biopsy, flow cytometry and FISH. We review the literature and discuss the differential diagnosis, clinical presentation, cytological and immunophenotypical characteristics of this unique case that raises very interesting questions regarding this new entity.