Incidence and Prevalence
- 0.5 per 100,000/year: LGGs in the supratentorial brain comprise more than half of the tumors in this space in children. The incidence of these tumors is roughly 5 per million children per year, with most being astrocytomas. The remaining minority are gangliogliomas, mixed gliomas, oligodendrogliomas, and the occasional dysembryoplastic neuroepithelial tumor, desmoplastic ganglioglioma, and pleomorphic xanthoastrocytoma.
By histological subtypes
In 2012 the Central Brain Tumor Registry of the United States published its statistical report on the occurrence of brain tumors in children in the United States covering the years 2005 to 2009 (22). At the time there were roughly 83.1 million children in the country. The following incidence of brain tumors in children ranging in age from 0 to 19 years were found:
- Grade I astrocytomas: The incidence of grade I astrocytomas is 0.8 per 100,000 per year. Grade I or pilocytic astrocytomas make up 5% of all gliomas and are the most frequent type of brain tumor in children. Most are located in the cerebellum.
- Grade II astrocytomas: The incidence of grade II astrocytomas is 0.3 per 100,000 per year
- Gangliogliomas and other neuronal tumors: The incidence of gangliogliomas, other mixed glial-neuronal tumors and neuronal tumors is 0.3 per 100,000 per year.
- Oliogodendrogliomas: The incidence of oligodendrogliomas is 0.06 per 100,000 children per year. Oligodendrogliomas make up 2.5% of all cerebral tumors and 5% of all gliomas (7, 8).
Others have reported on the occurrence of the following tumors:
- Subependymomas: Subependymomas are grade I tumors with a very low incidence (10).
- Subependymal giant cell astrocytomas: These tumors appear in 6–16% of patients with tuberous sclerosis.
- Pleomorphic xanthoastrocytomas: 1% of all astrocytomas are pleomorphic xanthoastrocytomas.
- Peak incidence 5–9 years age: The most common LGG in children, the pilocytic astrocytoma, occurs most commonly in children between 5 and 19 years of age with a peak incidence between 5 and 9 years (22). Gangliogliomas have a peak incidence in children at about the same time (9.5 years) (21). Fibrillary astrocytomas are less common and tend to occur in adolescents, while pilomyxoid astrocytomas occur most commonly in infants and young children.
- Male slightly more than female: The incidence of gliomas of any grade in males is 7.1 per 100,000 as compared to 5 per 100,000 in females. These statistics have not been broken down into benign vs. malignant neuroepithelial tumors.
- Not known: There is no data on geographical influence.
- Not known
Relationships to Other Disease States and Syndromes
- Tuberous sclerosis: SEGAs are present with tuberous sclerosis.
- Neurofibromatosis: Neurofibromatosis type I is associated with an increased risk of LGG.