Optic nerve glioma classification
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
Overview
Optic nerve glioma may be classified into several subtypes based on microscopic histopathology, anatomic location and association with neurofibromatosis type 1. Optic pathway gliomas are classified according to WHO classification into two subtypes: pilocytic astrocytoma and fibrillary astrocytoma. Optic nerve gliomas may be classified according to anatomic location into two subtypes: anterior tumors and posterior tumors.
Classification
Optic nerve glioma may be classified into several subtypes based on microscopic histopathology, anatomic location and association with neurofibromatosis type 1. Optic pathway gliomas are classified according to WHO classification into two subtypes: pilocytic astrocytoma and fibrillary astrocytoma. Optic nerve gliomas may be classified according to anatomic location into two subtypes: anterior tumors and posterior tumors. The majority of cases of optic nerve glioma are pilocytic. About 60% of optic pathway astrocytomas are pilocytic and 40% are fibrillary. Optic nerve gliomas are classified as low-grade astrocytomas. Histologically, optic nerve gliomas are identical to pilocytic astrocytomas. Optic nerve gliomas may be classified into several subtypes based on anatomic location, and whether or not they are associated with neurofibromatosis type 1. Optic nerve gliomas may be classified according to anatomic location into two subtypes: anterior tumors and posterior tumors.
- According to their location along the optic pathway, the two major categories are:
Anterior visual pathway
- Orbital
- Intracanalicular
- Intracranial prechiasmal lesions.
Most of anterior visual pathway tumors are classified as pilocytic astrocytomas and they occur most frequently in prepubertal children.[1]
Posterior visual pathway
- Optic chiasm
- Hypothalamus
- Anterior third ventricle
Most of posterior visual pathway tumors are classified histologically as pilocytic astrocytomas, and occasionally gangliogliomas. Hypothalamic and chiasmal lesions present at a mean age of about three years.[2] About 10% of optic pathway tumors are located within an optic nerve, one third of the tumors involve both optic nerve and chiasm, another one third involves predominantly the chiasm itself, and one fourth involves predominantly the hypothalamus. 5 5% of optic nerve gliomas are multicentric.
Association with NF1
Neurofibromatosis type 1 tumors are more likely to involve anterior visual pathway. Optic nerve gliomas without an association with neurofibromatosis type 1 are more frequent in the posterior visual pathway.[3] In children diagnosed with NF-1, approximately 15% develop optic gliomas.[4] [5] Twenty to forty percent of optic gliomas occur in children with NF-1.
References
- ↑ Tenny RT, Laws ER, Younge BR, Rush JA (1982). "The neurosurgical management of optic glioma. Results in 104 patients". J Neurosurg. 57 (4): 452–8. doi:10.3171/jns.1982.57.4.0452. PMID 7108594.
- ↑ Benes V, Julisová I, Julis I (1990). "Our treatment philosophy of gliomas of the anterior visual pathways". Childs Nerv Syst. 6 (2): 75–8. PMID 2340532.
- ↑ Taylor T, Jaspan T, Milano G, Gregson R, Parker T, Ritzmann T; et al. (2008). "Radiological classification of optic pathway gliomas: experience of a modified functional classification system". Br J Radiol. 81 (970): 761–6. doi:10.1259/bjr/65246351. PMID 18796556.
- ↑ Listernick R, Louis DN, Packer RJ, Gutmann DH (1997). "Optic pathway gliomas in children with neurofibromatosis 1: consensus statement from the NF1 Optic Pathway Glioma Task Force". Ann Neurol. 41 (2): 143–9. doi:10.1002/ana.410410204. PMID 9029062.
- ↑ Listernick R, Charrow J, Greenwald M, Mets M (1994). "Natural history of optic pathway tumors in children with neurofibromatosis type 1: a longitudinal study". J Pediatr. 125 (1): 63–6. PMID 8021787.