Follicular lymphoma is an indolent B-cell non-Hodgkin lymphoma typically characterized by the t(14;18)(q32;q21) translocation resulting in B-cell lymphoma 2 (BCL2)/immunoglobulin heavy chain (IGH) fusion. Nontranslocation variants are rare and may present with atypical clinical features that complicate diagnosis. The patient's presentation initially resembled infectious mononucleosis due to a false-positive monospot test; however, subsequent workup revealed follicular lymphoma lacking the canonical BCL2/IGH translocation. Extensive infectious, autoimmune, and nutritional evaluation was unrevealing. Cervical lymph node biopsy demonstrated follicular lymphoma with uniform BCL2 expression but no detectable BCL2/IGH fusion by Fluorescence in Situ Hybridization (FISH), confirming nontranslocation follicular lymphoma. The patient achieved complete remission after six cycles of obinutuzumab, cyclophosphamide, vincristine, and prednisone. This case illustrates a rare presentation of nontranslocation follicular lymphoma mimicking infectious mononucleosis and emphasizes the importance of reconsidering hematologic malignancy in patients with persistent mucocutaneous inflammation and incongruent laboratory findings.
Barsh et al. (Fri,) studied this question.