Hypereosinophilia in Acute Lymphoblastic Leukemia: Two Cases with Review of Literature.

Eosinophilia is rare in acute leukemia at presentation. Discrete reports and case studies in recent years have created significant interest in the field of "Acute leukemia with eosinophilia". We herein present two cases of eosinophilia in association with acute lymphoblastic leukemia with brief review of literature in this field. First case is about 21-year-old female who presented with mediastinal mass along with leukocytosis and hypereosinophilia. On evaluation, she was found to have T cell acute lymphoblastic leukemia. After ruling out benign causes of eosinophilia, she was treated with modified BFM-90 protocol. Her eosinophilia resolved after 4 weeks of induction therapy. Second case is about 32-year-old male who was diagnosed as a case of mixed phenotype leukemia (B cell/myeloid type) along with severe eosinophilia. His hypereosinophilia finally resolved by week 16 of modified BFM-90 protocol. Diagnosing ALL is challenging when eosinophilia is the initial presentation. These two cases emphasize on the importance of considering ALL amongst one of the etiological causes of eosinophilia as delay in diagnosis endangers patient's life at risk. Also eosinophilia per se is an independent poor risk factor, hence prompt diagnosis and early treatment is the key in all such cases.