Hemophagocytic lymphohistiocytosis onset during induction therapy for precursor B-cell acute lymphoblastic leukemia.

We report the clinical course of a child with precursor B-cell acute lymphoblastic leukemia who developed fever, hepatosplenomegaly, and refractory thrombocytopenia after initiation of chemotherapy. Bone marrow aspiration on Day 8 of induction showed new onset of hemophagocytosis and he met clinical, laboratory, and histopathologic criteria for hemophagocytic lymphohistiocytosis. His symptoms improved significantly after an increased dosage of steroids.