Gliomatosis cerebri mimicking chemotherapy-induced leukoencephalopathy in a patient with non-Hodgkin's lymphoma.

Patients with hematological malignancies may develop white matter lesions, which are usually associated with chemotherapy. Magnetic resonance imaging (MRI) is the imaging modality of choice for identifying chemotherapy-induced, or "toxic", leukoencephalopathy. Brain biopsy in patients with hematological malignancies suspected of sustaining toxic leukoencephalopathy has rarely been performed, because its characteristic MRI findings are considered pathognomotic. Biopsy may be indicated in atypical cases, however, and it may yield unexpected results. We describe a case with white matter lesions that developed in an elderly man treated for non-Hodgkin's lymphoma. The lesions, initially diagnosed with toxic leukoencephalopathy based on MRI findings, turned out to be gliomatosis cerebri.