Chiasmatic gliomas with diencephalic syndrome in infants: challenges in the diagnosis and treatment

Infant hypothalamic-chiasmatic gliomas demonstrate aggressive behavior and poor response to chemotherapy. Diencephalic syndrome is often the first and, for a long time, the only symptom of these tumors, which leads to diagnostic delay. Diencephalic syndrome has been reported as an adverse prognostic factor in pediatric low-grade gliomas. Alternative therapies such as novel molecular targeted therapies are particularly needed for these patients. Here we report two clinical cases of infants with KIAA1549–BRAF rearranged hypothalamic/chiasmatic gliomas who presented with diencephalic syndrome and progressed on standard chemotherapy. Treatment with the MEK inhibitor trametinib resulted in a significant reduction in tumor size and the normalization of the weight curve in both cases. The patient's parents gave their consent to the use of their child's data, including photographs, for research purposes and in publications.