Molecular and Mechanistic Divergence of Seizures in Pediatric Acute Lymphoblastic Leukemia: CNS Infiltration Versus Chemotherapy-Induced Neurotoxicity

Neurological complications, particularly seizures, represent a significant and often under-recognized clinical challenge in pediatric hematologic malignancies. Distinguishing CNS leukemia-associated epilepsy from chemotherapy-induced neurotoxicity is critical for optimizing therapy but remains difficult due to overlapping clinical presentations. This review highlights the distinct molecular mechanisms underlying these two entities. CNS leukemia-associated seizures are primarily driven by blood–brain barrier (BBB) disruption following leukemic infiltration, which triggers a neuroinflammatory cascade involving pro-inflammatory cytokines such as IL-6 and TNF-α, and impairs glutamate homeostasis. In contrast, chemotherapy-induced seizures, particularly those associated with high-dose methotrexate, arise from disrupted folate metabolism, intracellular oxidative stress, and subsequent N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity. We provide a comparative analysis of these pathways, integrating current evidence on pharmacogenomic susceptibility—including polymorphisms in methylenetetrahydrofolate reductase (MTHFR) and drug transporter genes—as well as epigenetic factors. By synthesizing these molecular insights, we propose a mechanistic framework for precise clinical differentiation, which may inform biomarker-driven diagnostic approaches and targeted neuroprotective strategies in this vulnerable population.