Purpose:
Neurotoxicity is an established adverse event associated with udarabine therapy. Severe leukoencephalopathy occurs in 2.4% of patients receiving udarabine, and vision loss is a common presenting symptom. On MRI, fludarabine leukoencephalopathy generally demonstrates symmetric diffusion restriction and T2 prolongation in the bilateral periventricular white matter. We present a case of early fludarabine leukoencephalopathy manifest by a single focus of diffusion restriction, mimicking an acute infarct. 

Case Report:
54-year-old female with metastatic follicular lymphoma complicated by multiple recurrences underwent lymphodepletion with fludarabine/cyclophosphamide 3 weeks prior to receiving CAR T-cell infusion. Patient then presented for marked vision loss and mild cognitive deficits 6 weeks following chemotherapy. Brain MRI was suspicious for acute infarct. She was treated with high dose steroids for presumed CAR T-cell associated neurotoxicity given proximity in time to the infusion. However, CSF analysis from a lumbar puncture showed no expansion of CAR T-cells in CSF, and the patient experienced worsening vision. She was subsequently diagnosed with fludarabine leukoencephalopathy. 

Image Findings:
Initial brain MRI demonstrated focal diffusion restriction and T2 prolongation within right occipital periventricular white matter which was attributed to acute ischemia, although the location was noted to be atypical for an acute infarct. 3 subsequent exams performed over the next 2 months demonstrated expansion of diffusion restriction and T2 prolongation into the bilateral occipital periventricular white matter, raising the possibility of toxic/metabolic leukoencephalopathy or PRES. The most recent exam showed further progression of T2 prolongation, symmetrically involving bilateral occipital and parietal white matter and the corpus callosum with resolution of diffusion restriction. Abnormal contrast enhancement was never present. 

Summary:
Focal periventricular diusion restriction may represent an early manifestation of neurotoxicity in a patient who has received fludarabine.

Early Fludarabine Leukoencephalopathy Mimicking Acute Infarct

[Virtual Conference Page](https://event.vconferenceonline.com/microsite/html/login.aspx?id=1551&rlp=1)

[ASNR Website] (https://www.asnr.org//annualmeeting)

[Educational Exhibits](https://www.morressier.com/event/asnr2020exhibit/5e5d0be000701ceba4a26941)