A 77-year-old man presented with cognitive decline and visual disturbance. Symptoms had been progressive for 6 weeks. He had chronic lymphocytic leukemia and was on ofatumumab. He had previously received alemtuzumab, which was discontinued 4 months before his presentation because of adverse effects. Examination demonstrated disorientation, right homonymous hemianopia, and inability to read. Writing and other language abilities were preserved. Laboratory workup was remarkable for pancytopenia with an absolute neutrophil count of 330/mm3. Brain magnetic resonance imaging (MRI) demonstrated a lesion affecting the subcortical white matter in the left occipital lobe and extending to the splenium of the corpus callosum without contrast enhancement of restricted diffusion (Figure 1). Cerebrospinal fluid (CSF) analysis showed a normal cell count and chemistry. Polymerase chain reaction for the John Cunningham virus (JCV) was positive, establishing the diagnosis of progressive multifocal leukoencephalopathy (PML). Testing for the human immunodeficiency virus and other infectious agents, as well as CSF cytology, was negative. He declined rapidly and died shortly after admission.
Figure 1.
Brain MRI fluid-attenuated inversion recovery sequence, axial plane (A) demonstrates a hyperintense lesion in the left occipital white matter and splenium of the corpus callosum, with sparing of the cortex (arrows). There is no abnormal enhancement (B, gadolinium-enhanced T1-weighted image) or restricted diffusion (C, diffusion-weighted image and D, apparent diffusion coefficient). MRI indicates magnetic resonance imaging.
Alexia without agraphia is a disconnection syndrome characterized by inability to read with preserved writing. It is caused by left occipitotemporal lesions involving the callosal splenium, which prevents visual information from reaching the angular gyrus for comprehension.1 Stroke is the most common cause. This syndrome has rarely been reported as the initial manifestation of PML.2 In our case, the combination of a hematologic malignancy and treatment with monoclonal antibodies likely precipitated the reactivation of the JCV, which led to PML.3,4
Acknowledgment
The author thanks Jennifer Han, MD, for her assistance in obtaining the MRI images.
Footnotes
Declaration of Conflicting Interests: The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The author received no financial support for the research, authorship, and/or publication of this article.
ORCID iD: J. David Avila, MD 
https://orcid.org/0000-0001-8671-671X
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