Hypereosinophilic syndrome preceding a diagnosis of B-cell lymphoma:

Introduction:Hypereosinophilic syndrome (HES) is a rare condition characterized by eosinophilia and organ destruction secondary to eosinophilic infiltration. The coexistence of primary B-cell lymphoma and hypereosinophilic syndrome is extremely rare. We present a case of HES that preceded the diagnosis of diffuse large B-cell lymphoma.Case report:A 70-year-old man presented with a 3-month history of diarrhea and 30-pound weight loss. Complete blood count showed a white blood cell count of 7452/µL with eosinophils of 42% (absolute eosinophil count 3130). Colonoscopy showed eosinophilic infiltrate in the lamina propria and muscularis mucosa. Bone marrow biopsy showed elevated myeloid: erythroid ratio (6:1), increased mature and immature eosinophilic infiltration (10% of nucleated cells). Molecular studies were negative for Fip1-like1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) translocation and PDGFRB and FGFR mutations, indicating nonclonal eosinophilia. Treatment was initiated with predn...