Case Presentation:
A 10-year-old female presented with 3 weeks of progressively worsening
nausea and vomiting was found to have a large complex partially solid,
partially cystic intra-axial mass in the left temporal parietal lobe
with internal calcifications and mild mass effect on computed tomography
(CT), concerning for primary brain tumor.
Neurological examination demonstrated right-sided pronator drift but was
otherwise unremarkable. Magnetic resonance imaging (MRI) revealed a left
temporal parietal cortically based cystic lesion with a solid enhancing
component with surrounding vasogenic edema (Fig A-B).
The patient underwent craniotomy for gross total resection.
Histopathological analysis revealed a highly cellular spindle cell tumor
with brisk mitotic activity, positive immunohistochemical staining for
Olig2 and ATRX, and negative for GFAP (Fig C-F). DNA methylation
profiling was consistent with a diagnosis of CNS high grade
neuroepithelial tumor with MN1 alteration, confirmed on
Next-Generation Sequencing (NGS) as a MN1-BEND2 fusion. Germline
sequencing demonstrated an ATM heterozygous pathogenic variant
(ATM c.103C>T). The patient remains disease free 8 months
after diagnosis in the absence of adjuvant therapy.