Central nervous system involvement at the time of presentation in acute promyelocytic leukemia.

Central nervous system (CNS) involvement is rarely observed in acute promyelocytic leukemia (APML). Most cases of CNS involvement occur at relapse rather than at presentation. Because of the extremely low incidence of CNS disease, diagnostic lumbar puncture is not routinely required and prophylactic intrathecal chemotherapy is not routinely administered. Here, we describe a teenage patient with newly diagnosed APML, chloromas, and symptomatic CNS involvement confirmed by MRI and cerebrospinal fluid (CSF) findings.