Methotrexate-induced myelopathy mimicking subacute combined degeneration of the spinal cord.

Methotrexate (MTX), a folate antagonist, is widely used to treat hematological malignancies. Although it is known to cause myelopathy, little is known about the pathophysiology and natural history of this myelopathy. We describe a 42-year-old woman with acute lymphoblastic leukemia who was treated with chemotherapy consisting of intrathecal MTX who developed a progressive myelopathy. The myelopathy mimicked, radiologically, subacute combined degeneration (SACD) of the spinal cord. This myelopathy mimicking SACD could be explained by the folate antagonism of MTX. The progressive clinical signs and serial MRI in this patient further our understanding of the natural progression of this myelopathy.