Isolated central nervous system relapse in childhood acute promyelocytic leukemia

Central nervous system (CNS) involvement is rare in acute promyelocytic leukemia (APL). The majority of CNS relapses occur in patients with hyperleukocytosis at presentation, and the optimal management of such patients is still controversial. We describe a 13-year-old boy with APL who developed an isolated CNS relapse after first-line treatment with all-trans retinoic acid and chemotherapy. A second remission was achieved with a regimen consisting of intrathecal chemotherapy, intravenous high-dose cytarabine, and oral 6-mercaptopurine. All-trans retinoic acid was avoided owing to severe complications during initial therapy. The patient remains in molecular remission at 9 months after autologous stem cell transplant. Prognostic factors of CNS relapse in children with APL are needed to define the indications for CNS prophylaxis in this group of patients.