TY - JOUR T1 - Corticosteroid sensitivity in gliomatosis cerebri delays diagnosis JF - Practical Neurology JO - Pract Neurol SP - 309 LP - 311 DO - 10.1136/practneurol-2015-001125 VL - 15 IS - 4 AU - Jan Bittar AU - Carlos Kamiya-Matsuoka AU - Pedro C Barata AU - Soo-Hyun Lee-Kim AU - Adriana Olar AU - Ivo W Tremont-Lukats Y1 - 2015/08/01 UR - http://pn.bmj.com/content/15/4/309.abstract N2 - Gliomatosis cerebri is a rare malignant tumour originating from cerebral glial cells. Most experts currently view gliomatosis cerebri as a pattern of extensive glioma infiltration encompassing at least three cerebral lobes.1 It occurs at any age, with peak incidence between 40 years and 50 years and it is slightly more common in men.2 On MRI, gliomatosis cerebri shows no, or minimal, contrast enhancement; however, it has a diffuse hyperintense infiltrative process on T2-weighted fluid-attenuated inversion recovery (FLAIR) sequence. It is usually possible to diagnose gliomatosis cerebri using an open biopsy or a stereotactic biopsy. Despite treatment, its median survival varies from 6 months to 39 months.3 We report an unusual presentation of gliomatosis cerebri, which underscores the difficulty in pinpointing the correct diagnosis after corticosteroids have modified the disease course.A 78-year-old woman had an episode of acute onset slurred speech and confusion. Her initial CT scan of head showed diffuse left hemispherical white matter hypodensity with sulcal effacement and minimal midline shift to the right. Cerebrospinal fluid (CSF) examination suggested viral encephalitis for which she was empirically given intravenous dexamethasone and acyclovir, with oral levetiracetam 500 mg twice daily. After initially improving, she rapidly worsened with corticosteroid tapering. A repeat CT scan of head showed no change. She took dexamethasone 4 mg twice daily before undergoing a brain biopsy, which showed mild hypercellularity suspicious but not definitive for glioma.Two weeks later, we saw her for a second opinion. The MRI of … ER -