High-dose methotrexate-related pneumonitis in a child with acute lymphoblastic leukemia.

Introduction: Methotrexate is administered through different routes to treat childhood acute lymphoblastic leukemia. Toxicities of low, intermediate, or high doses of methotrexate have been described in the literature. Methotrexate-induced or related pneumonitis is a rare complication that leads, in most cases, to discontinuing this drug.