Abstract General Information

Title

EXTRA NERVOUS SYSTEM METASTASIS DUE TO MIDLINE DIFFUSE GLIOMA: CASE REPORT AND LITERATURE REVIEW

Case Presentation, Discussion, and Final Comments.

CASE PRESENTATION
A 7-year-old girl who has a progressively worsening headache and vomits in the last 20 days. She complained about low visual acuity but the ophthalmological exam did not show any alterations. No other complaints. The past history and the physical exam showed nothing significant. A magnetic resonance imaging (MRI) revealed a diffusely expanded pons compatible with Diffuse Intrinsic Pontine Glioma (DIPG). Stereotactic biopsy was performed and the histological analysis revealed an astrocytoma. The immunohistochemistry and direct sequencing showed p53 negative, proliferation index Ki67 of 10-15% and a mutation on HIST1H3B gene. The treatment with radiotherapy was initiated.
The patient followed up with progressive neurological deterioration. A new MRI showed hyperintense lesions on midbrain, both thalamus and cortex of cerebrum. Another treatment with radiation therapy and chemotherapy was performed. During an outpatient consultation, a new MRI was evaluated, which revealed the presence of multiple lesions in the spine, ischio and sternum. It was performed a transpedicular biopsy guided by CT in one of this vertebral lesions. Histopathological analysis revealed that they were metastasis due to glial neoplasia.

DISCUSSION
DIPG is an aggressive tumor of the brainstem and extraneural metastases are rarely reported and poorly characterized. DIPG most commonly affects the pediatric population. The mean age at diagnosis are 6-7 years. It represents approximately 20% of all pediatric CNS tumors (1). Unfortunately, DIPG has a poor prognosis, and the median survival is generally less than 1 year independently from the treatment received.
These tumors are not surgically resectable due to their anatomic location, which limits tissue available for diagnosis and molecular study. However, recent studies have revealed molecular characteristics of diffuse midline gliomas that are distinct from hemispheric pediatric and adult gliomas (2, 3).

FINAL COMMENTS
Patients with appropriate age and typical image in MRI of DIPG allow treatment without biopsy, but in reference centers the histopathological and genetic study warrant the development of other treatments. Despite of all the development in neurosurgical technology, DIPG continues to be a disease with small progress in overall survival. This uncommon presentation of metastatic dissemination of midline diffuse glioma is important to be presented due to the need to better understand its behavior.

Keywords

Diffuse midline glioma, Diffuse intrinsic pontine glioma (DIPG), Metastasis, Extraneural disease, HIST1H3B