Optic nerve sheath meningiomas (ONSM) are rare benign tumors of the optic nerve. 60–70% of cases occur in middle age females, and is more common in older adults (mean age 44.7 years). It is also seen in children, but this is rare. The tumors grow from cells that surround the optic nerve, and as the tumor grows, it compresses the optic nerve. This causes loss of vision in the affected eye.[1] Rarely, it may affect both eyes at the same time.[2]
Radiation treatment of ONSM
It is typically a slow growing tumor, and has never been reported to cause death. However, there is concern that the tumor can grow into the brain and cause other types of neurological damage. In some patients, the tumor grows so slowly that treatment is not necessary. Standard treatments are observation, surgery, radiation therapy, and combinations of the above.[1]
The most common symptom of ONSM is a gradual loss of vision in one eye. In a minority of patients this may be intermittent, at least to begin with. Less common symptoms include pain in the affected eye, protrusion of the eye, or double vision.[2]
Natural history
ONSM does not improve without treatment. In many cases, there is gradual progression until vision is lost in the affected eye. However, this takes at least several months to occur, and a minority of patients remain stable for a number of years.[2][3][4]
Diagnosis
Clinical examination will show an abnormal optic disc, either swollen or atrophic. Optociliary shunt vessels may be seen; the combination of these with progressive visual loss and optic disc atrophy is known as the Hoyt-Spencer triad. Visual acuity is usually but not always reduced.
When ONSM is suspected, MRI of the brain or orbits should be performed. This will usually show characteristic findings and confirm the diagnosis.[5]
Treatment
Most ophthalmologists will not advocate any treatment unless visual loss is present and ongoing. Reports of patients with ONSM having no change in their vision for multiple years are not uncommon. If loss of vision occurs, radiation therapy will improve vision in about ⅓ of cases, and preserve vision in about ⅓ of cases. Surgery has traditionally been associated with rapid deteroriation of vision. However, newer surgical techniques may prove better for the treatment of ONSM.[4][6][7]
Incidence
About 1–2% of all meningiomas are optic nerve sheath meningiomas. Meningiomas have an incidence of ~4.18/100,000 persons each year. Thus, ~10,000 meningiomas are diagnosed in the US each year; corresponding to ~100 cases of ONSM each year in the US. The actual number of meningiomas is likely much higher as it is very common in elderly women[citation needed]. ONSM comprises about 2% of orbital tumors, and about 10% of optic nerve lesions.[8]
Neurofibromatosis type II (NF-2) affects around 9% of ONSM patients, where the incidence in the general population is around 0.03–0.05%. Thus NF-2 is felt to be a risk factor for the development of ONSM.[1]
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Optic nerve sheath meningiomas ONSM are rare benign tumors of the optic nerve 60 70 of cases occur in middle age females and is more common in older adults mean age 44 7 years It is also seen in children but this is rare The tumors grow from cells that surround the optic nerve and as the tumor grows it compresses the optic nerve This causes loss of vision in the affected eye 1 Rarely it may affect both eyes at the same time 2 Radiation treatment of ONSM It is typically a slow growing tumor and has never been reported to cause death However there is concern that the tumor can grow into the brain and cause other types of neurological damage In some patients the tumor grows so slowly that treatment is not necessary Standard treatments are observation surgery radiation therapy and combinations of the above 1 Contents 1 Symptoms and signs 2 Natural history 3 Diagnosis 4 Treatment 5 Incidence 6 ReferencesSymptoms and signs Edit MRI of a patient with ONSM The most common symptom of ONSM is a gradual loss of vision in one eye In a minority of patients this may be intermittent at least to begin with Less common symptoms include pain in the affected eye protrusion of the eye or double vision 2 Natural history EditONSM does not improve without treatment In many cases there is gradual progression until vision is lost in the affected eye However this takes at least several months to occur and a minority of patients remain stable for a number of years 2 3 4 Diagnosis EditClinical examination will show an abnormal optic disc either swollen or atrophic Optociliary shunt vessels may be seen the combination of these with progressive visual loss and optic disc atrophy is known as the Hoyt Spencer triad Visual acuity is usually but not always reduced When ONSM is suspected MRI of the brain or orbits should be performed This will usually show characteristic findings and confirm the diagnosis 5 Treatment EditMost ophthalmologists will not advocate any treatment unless visual loss is present and ongoing Reports of patients with ONSM having no change in their vision for multiple years are not uncommon If loss of vision occurs radiation therapy will improve vision in about of cases and preserve vision in about of cases Surgery has traditionally been associated with rapid deteroriation of vision However newer surgical techniques may prove better for the treatment of ONSM 4 6 7 Incidence EditAbout 1 2 of all meningiomas are optic nerve sheath meningiomas Meningiomas have an incidence of 4 18 100 000 persons each year Thus 10 000 meningiomas are diagnosed in the US each year corresponding to 100 cases of ONSM each year in the US The actual number of meningiomas is likely much higher as it is very common in elderly women citation needed ONSM comprises about 2 of orbital tumors and about 10 of optic nerve lesions 8 Neurofibromatosis type II NF 2 affects around 9 of ONSM patients where the incidence in the general population is around 0 03 0 05 Thus NF 2 is felt to be a risk factor for the development of ONSM 1 References Edit a b c Dutton JJ 1992 Optic nerve sheath meningiomas Surv Ophthalmol 37 3 167 83 doi 10 1016 0039 6257 92 90135 G PMID 1475751 a b c Saeed P Rootman J Nugent RA White VA MacKenzie IR Koornneef L 2003 Optic nerve sheath meningiomas Ophthalmology 110 10 2019 30 doi 10 1016 S0161 6420 03 00787 5 PMID 14522782 Wright JE Call NB Liaricos S 1980 Primary optic nerve meningioma Br J Ophthalmol 64 8 553 558 doi 10 1136 bjo 64 8 553 PMC 1043761 PMID 7426572 a b Turbin RE Thompson CR Kennerdell JS Cockerham KP Kupersmith MJ May 2002 A long term visual outcome comparison in patients with optic nerve sheath meningioma managed with observation surgery radiotherapy or surgery and radiotherapy Ophthalmology 109 5 890 9 discussion 899 900 doi 10 1016 S0161 6420 02 01017 5 PMID 11986093 Lindblom B Truwit CL Hoyt WF April 1992 Optic nerve sheath meningioma Definition of intraorbital intracanalicular and intracranial components with magnetic resonance imaging Ophthalmology 99 4 560 6 doi 10 1016 s0161 6420 92 31932 3 PMID 1584575 Narayan S Cornblath WT Sandler HM Elner V Hayman JA June 2003 Preliminary visual outcomes after three dimensional conformal radiation therapy for optic nerve sheath meningioma Int J Radiat Oncol Biol Phys 56 2 537 43 doi 10 1016 S0360 3016 03 00005 1 PMID 12738331 Landert M Baumert BG Bosch MM Lutolf UM Landau K June 2005 The visual impact of fractionated stereotactic conformal radiotherapy on seven eyes with optic nerve sheath meningiomas J Neuroophthalmol 25 2 86 91 doi 10 1097 01 wno 0000165105 78365 22 PMID 15937428 S2CID 39931589 Lindegaard J Heegaard S Prause JU February 2002 Histopathologically verified non vascular optic nerve lesions in Denmark 1940 99 Acta Ophthalmol Scand 80 1 32 7 doi 10 1034 j 1600 0420 2002 800107 x PMID 11906301 Retrieved from https en wikipedia org w index php title Optic nerve sheath meningioma amp oldid 1088049920, wikipedia, wiki, book, books, library,
