Bilateral Thalamic Glioma: A Case Report

Abstract

Bilateral thalamic primary gliomas are an exceedingly rare entity. Symptomology heralding a workup and diagnosis of bithalamic gliomas is diverse and varies between the pediatric and adult populations. Herein, we present a case of a 63-year-old female patient who presented with progressive gait imbalance and fatigue, prompting an outpatient brain MRI, remarkable for marked expansion of the bilateral thalami secondary to non-enhancing, T2-weighted-fluid-attenuated inversion recovery (T2-FLAIR) bright bithalamic lesions. The patient underwent a right frontal frameless stereotactic biopsy of the right thalamic lesion, with immuno-histology indicating a high-grade anaplastic astrocytoma with molecular features of glioblastoma (GBM). The patient's functional status declined precipitously in the month following her diagnostic biopsy, precluding any therapy, and the patient ultimately pursued home hospice care without further treatment. This case details the clinical management of a very rare tumor, supplementing the available literature on the progression and treatment of this rare disease.

Keywords: bithalamic glioma; glioblastoma (gbm); histone lysine-to-methionine mutation (h3k27m); o-6-methylguanine-deoxyribonucleic acid methyltransferase (mgmt); telomerase reverse transcriptase (tert).

Figure 1. Axial T1-weighted post-contrast MRI

The image demonstrates non-enhancing expansile lesions in the right greater than left thalami.

Figure 2. T2-weighted magnetic resonance image

The image demonstrates heterogeneously T2 hyperintense lesions in the right greater than left thalami with associated elevated T2 signal in the right internal capsule and adjacent white matter.

Figure 3. Tumor immunohistochemistry

(A) IDH-1 was negative, consistent with wild-type. (B) ATRX was retained, consistent with wild-type. (C) P-53 was slightly positive, consistent with wild-type. (D) H3K27M was negative, consistent with wild-type and not mid-line diffuse glioma. IDH-1: isocitrate dehydrogenase 1; ATRX: α thalassemia/mental retardation syndrome, X-linked gene; P-53: tumor protein 53; H3K27M: histone lysine-to-methionine mutation