**15.3 Optic-hypothalamic glioma**

Optic pathway-hypothalamic gliomas are rare astrocytic tumors that are more among young children. They comprise approximately 2% of all central nervous system tumors and account for 3–5% of pediatric intracranial tumors.

OPG was classified by Dodge et al. into the following three stages: (A) limited to the optic nerve; (B) involving optic chiasma (with or without extension to the optic nerve) and (C) involvement of hypothalamus and other structures [41].

The tumours do not produce symptoms at an early stage. The symptoms can be due to impingement on optic nerve or chiasma which leads to visual disturbances, involvement of hypothalamus causing endocrinopathies and hypothalamic dysfunction such as the diencephalic syndrome. It can also cause csf outflow block leading to hydrocephalus [42].

Surgery has a limited role in the treatment of these tumours as they lie close to critical structures. It is usually limited to establishing a histopathological diagnosis or debulking in case of large tumours. Although Gross total resection of low-grade glioma is strongly associated with improvement of both OS and PFS but Aggressive resection, often leads to blindness, hypothalamic damage and cognitive dysfunctions [43].

### *15.3.1. Chemotherapy*

Carboplatin and Vincristine is the most frequently recommended first-line chemotherapy, and it is considered to be the standard treatment of OPG [44].
