Severe Methotrexate Toxicity Following a Capizzi Cycle in an Obese Adolescent With Acute Lymphoblastic Leukemia and Hepatic Steatosis.

Methotrexate is a major component of pediatric leukemia treatment. While toxicities are common after high-dose methotrexate, escalating dose methotrexate (Capizzi methotrexate) is typically well-tolerated. We report an adolescent Hispanic female with pre-B acute lymphoblastic leukemia, preexisting obesity and hepatic steatosis who developed severe multiorgan failure following an escalating dose of methotrexate with delayed methotrexate excretion of 11 days. We identified one similar report in an obese adult; however, this case is the first to our knowledge involving a pediatric patient. With the rising incidence of obesity and associated comorbidities among children and adolescents with leukemia, attention to potential risks for this population is warranted.