The incidence of childhood central nervous system tumors in infants is about 6 per 100,000 children with glioma having the highest incidence at 1.38 per 100,000. A study by Wu et al. showed recurrent fusion of the NTRK gene in 10% of non-brainstem high grade glioma in very young children suggesting an oncogenic effect of the NTRK fusion genes.

Here we present a rare case of a full-term neonate who was noted to have widely splayed sutures and a bulging fontanelle at birth who was found to have infant-type hemispheric glioma with NTRK1 fusion.

A full-term infant with normal prenatal course, including a 20-week anatomy scan, was born with widely splayed sutures, bulging anterior fontanelle and head circumference >99^th percentile (40 cm). Head ultrasound showed severe hydrocephalus and a large intracranial mixed echogenicity lesion in the left cerebral hemisphere with hemorrhage. He had sustained leftward gaze, and video EEG revealed seizures. MRI demonstrated a large 6x7cm lesion, hydrocephalus with subfalcine herniation and mass effect on the brainstem (figure, A-B). He underwent biopsy and ventriculoperitoneal shunt placement. MRI 2 weeks later showed tumor enlargement, obstructive hydrocephalus and severe brainstem compression (figure, C-D). Pathology was consistent with infant-type hemispheric glioma with NTRK1 fusion. Due to the dismal prognosis, the family prioritized palliative care.

Infant-type hemispheric glioma, previously termed glioblastoma (GBM), is a rare, rapidly-growing congenital tumor, and prenatal imaging is often normal. Mixed-age hemorrhages and diffusion restriction is suggestive of the diagnosis. The neurotrophic tyrosine receptor kinase (NTRK) genes NTRK1, NTRK2, and NTRK3 are involved in infant-type hemispheric gliomas and are typically high grade in histology. A recent study by Torre et al. showed most NTRK-fused gliomas were hemispheric and had a higher prevalence in non-brainstem high grade gliomas in patients younger than 3 years old.