Acute lymphoblastic leukemia of childhood presenting as aplastic anemia: report of two cases.

Acute lymphoblastic leukemia is the most common malignancy in pediatric patients; its diagnosis is usually easy to establish as malignant lymphoblasts invade the bone marrow and peripheral blood. Some acute lymphoblastic leukemia patients may initially present with pancytopenia and a hypoplastic bone marrow leading to the initial diagnosis of aplastic anemia. In most of these patients clinical improvement occurs, with normalization of the complete blood count within six months, although recovery can also develop a few weeks after initiating steroid therapy. The etiologic relationship between the aplastic anemia features and the subsequent overt development of acute lymphoblastic leukemia has not been established. We describe the cases of two children who presented with severe infection and signs and symptoms of aplastic anemia confirmed by bone marrow aspirate and bone marrow biopsy that developed acute lymphoblastic leukemia thereafter. No specific therapy for aplastic anemia was administered, nevertheless a full spontaneous recovery was observed in both cases. Acute lymphoblastic leukemia was successfully treated with standard chemotherapy, both children remaining in complete remission 16 and 17 months after their initial aplastic anemia diagnosis.