Intrathecal Methotrexate–Induced Megaloblastic Anemia in Patients With Acute Leukemia

Abstract

Intrathecally administered methotrexate may result in megaloblastic changes in the bone marrow of leukemic patients. The morphologic clues suggestive of folate deficiency in patients with acute leukemia may be masked by coexisting factors, such as the effects of cytotoxic treatment, prior transfusions, or persistent changes from the leukemic clone itself. Caution should be exercised to avoid attributing these changes to the neoplastic process, since the prognosis and treatment for the conditions involved are totally different. Repeat examination of the bone marrow, obtaining folic acid and vitamin B(12) levels, and a therapeutic trial of folic acid may help identify and reverse these changes.