Detection of MRD positivity as an indicator of CNS relapse in AML and therapeutic approach

Acute myeloid leukaemia (AML) poses intricate diagnostic and therapeutic dilemmas. This report delves into the infrequent manifestation of central nervous system (CNS) involvement in AML, an elusive facet of the disease's clinical spectrum. We present the case of a young female who attained morphological remission following induction therapy and an allogeneic haematopoietic stem cell transplant (HSCT). Intriguingly, despite the absence of morphological AML in the bone marrow, persistent minimal residual disease (MRD) positivity led to a comprehensive evaluation, ultimately revealing CNS leukaemia. Effective treatment for CNS leukaemia, including intrathecal methotrexate, chemotherapy and craniospinal irradiation, was administered. After achieving remission, a second HSCT was performed, and she currently receives maintenance therapy. This case underscores the intricate diagnostic landscape of CNS leukaemia in AML and prompts inquiries about the potential nexus between MRD positivity and extramedullary disease.