Gliomatosis cerebri mimicking viral encephalitis in a 4-year-old child.

To cite: McCusker MW, McDonald MA, Looby S, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014203659 DESCRIPTION A 4-year-old boy presented with an afebrile right-sided focal seizure. MRI of the brain demonstrated an infiltrating fluid attenuated inversion recovery (FLAIR) hyperintense abnormality in the left frontal, temporal and occipital white matter, involving the temporal lobe cortex, without enhancement, microhaemorrhage or diffusion restriction (figure 1). The findings were interpreted as infectious encephalitis and intravenous acyclovir was started. Cerebrospinal fluid analysis revealed normal protein and white cell count, and was negative for viral, bacterial and mycobacterial agents. After initial improvement the focal seizures recurred. Repeat imaging after 28 days showed progression of the FLAIR abnormality with extension into both thalami (figure 2). The lesion was biopsied and histology showed diffusely infiltrating grade III astrocytoma. The patient was treated with radiotherapy but died 6 months later. Gliomatosis cerebri (GC) is an infiltrating glial tumour involving at least three cortical lobes. Presentation in children is uncommon: to our knowledge only eight cases in children younger than 5 years have been described. It typically presents with non-specific symptoms and signs including seizures, hemiparesis, ataxia, lethargy and symptoms of intracranial hypertension. 2 GC may mimic more common disorders, such as encephalitis and acute disseminated encephalomyelitis, resulting in delay in diagnosis and treatment. 5 Although prognosis is poor and GC is universally fatal, 2 there is evidence that treatment confers some short-term survival benefit. It is important, therefore, to include GC in the differential diagnosis in cases of widespread infiltrating brain lesions when the clinical features are atypical or unexpected, and to consider brain biopsy in those cases.