Successful Treatment of Isolated Central Nervous System Relapse with Intrathecal Chemotherapy in an Adolescent with Acute Promyelocytic Leukemia

Abstract

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) characterized by translocation of chromosomes 15 and 17 (t(15;17)), which rarely occurs in the pediatric population. Isolated central nervous system (CNS) relapse is particularly rare in children with APL, and a standard treatment has not yet been established. In this case, a 15-year-old male adolescent with APL had no CNS involvement at the initial diagnosis. After remission induction therapy with idarubicin, all-trans retinoic acid, and intrathecal (IT) cytarabine, a bone marrow (BM) study revealed morphological and cytogenetic complete remission. However, immature myeloid cells and blasts were observed in the cerebrospinal fluid (CSF). IT triple chemotherapy (ITT) consisting of cytarabine, methotrexate, and hydrocortisone was administered in addition to the planned systemic chemotherapy. ITT was performed weekly for 6 weeks with consolidation therapy, and then every 3 months for 2 years during the period of maintenance therapy. Abnormal immature cells were no longer detected after the second ITT administration. The patient survived without evidence of BM or CNS relapse until 1 year after treatment completion. The combination of IT chemotherapy might be a possible treatment option for CNS relapse in patients with APL, and further studies are needed to establish an optimal treatment strategy for them.