Objective:

NA

Background:

Infant-type hemispheric glioma (IHG) is a rare and aggressive brain tumor that primarily affects infants and newborns. Classified as a pediatric high-grade glioma, these tumors are typically driven by receptor tyrosine kinase (RTK) gene fusions. In this report, we discuss an infant diagnosed with a unique PPP1CB-ALK fusion variant of IHG, which responded favorably to treatment with the ALK inhibitor lorlatinib.

Design/Methods:

NA

Results:

We present an 8-month-old girl who was diagnosed with infant-type diffuse hemispheric glioma, ALK-altered subtype, in June 2023—a very rare diagnosis in this age group. The patient initially presented with twitching in her right arm, loss of truncal tone, and a strong preference for using her left side during motor activities when she was 5 months old. Upon examination, decreased muscle tone on the right side was noted, and the patient was unable to roll from back to tummy—milestones typically achieved at this age. EEG revealed continuous slowing with epileptiform discharges, predominantly in the left frontal and occipital regions. MRI imaging identified a large 9.0x4.9x6.0 cm heterogeneous, solid, and cystic mass in the left frontal, parietal, and temporal lobes. Given the size and location of the tumor, the neurosurgeon discussed the risks of aggressive resection, which included potential neurological deficits, excessive blood loss, and possible stroke. A biopsy was performed instead, confirming infant-type diffuse hemispheric glioma, ALK-altered subtype. The patient was started on lorlatinib (25mg), an ALK inhibitor, with MRI monitoring every three months. After initiation of lorlatinib, significant tumor shrinkage and reduction in enhancement were observed. The patient is scheduled for surgical resection in the coming months and was seen in our pediatric clinic for a routine follow-up visit.

Conclusions:

NA