Central nervous system relapse with multiple brain masses in an acute promyelocytic leukemia patient treated with all-trans retinoic acid

A 22-year-old woman with fever and bleeding tendency was given a diagnosis of acute promyelocytic leukemia (APL) on the basis of laboratory findings including a WBC count of 106 x 10(3)/microliter (90% blasts) and a platelet count of 1.6 x 10(4)/microliter. Induction therapy was started with all-trans retinoic acid (ATRA) and cytotoxic chemotherapy. After the patient achieved complete remission, ATRA was discontinued and consolidation chemotherapy was started. However, 4 months after onset, leukemic blasts were detected in cerebrospinal fluid. Temporal central nervous system remission was induced by intrathecal chemotherapy only. However, 2 months later, multiple focal mass lesions had developed in the brain. ATRA (45 mg/m2) was restarted together with multiple intrathecal injections of anticancer drugs, and a third remission was achieved. It is conceivable that the incorporation of ATRA in induction chemotherapy is related to the development of this rather rare complication of APL. The outcome in this case suggested orally administered ATRA may be effective in treating brain metastasis of APL.