Vestibular schwannoma

Vestibular schwannoma
Other namesAcoustic neuroma,[1] acoustic neurilemmoma, perineural fibroblastoma, neurinoma of the acoustic nerve, neurofibroma of the acoustic nerve, schwannoma of the acoustic nerve[2]
Bilateral schwannomas in a patient with neurofibromatosis 2
SpecialtyNeuro-oncology
SymptomsGradual hearing loss, dizziness, tinnitus
ComplicationsBrain tumor growth; unilateral facial paralysis, single-sided hearing loss
TypesSporadic vestibular schwannoma (VS); Neurofibromatosis type II (NF2)
Diagnostic methodHearing exam, MRI exam
PreventionTumor management
TreatmentRadiosurgery and radiotherapy
PrognosisVariable, based on size of tumor;[3][4] larger brain tumors may result in brainstem compression, headache, vomiting, vertigo, fatigue, mental disorientation, coma, and death;[3][4] results in less acute circumstances by advanced specialists in the field have reduced mortality rates to near 1% [5]
FrequencyVery rare [6][7][8]

A vestibular schwannoma (VS), also called acoustic neuroma, is a benign tumor that develops on the vestibulocochlear nerve that passes from the inner ear to the brain. The tumor originates when Schwann cells that form the insulating myelin sheath on the nerve malfunction. Normally, Schwann cells function beneficially to protect the nerves which transmit balance and sound information to the brain. However, sometimes a mutation in the tumor suppressor gene, NF2, located on chromosome 22, results in abnormal production of the cell protein named Merlin, and Schwann cells multiply to form a tumor. The tumor originates mostly on the vestibular division of the nerve rather than the cochlear division, but hearing as well as balance will be affected as the tumor enlarges.

The great majority of these VSs (95%) are unilateral, in one ear only. They are called "sporadic" (i.e., by-chance, non-hereditary). Although non-cancerous, they can do harm or even become life-threatening if they grow to press on other cranial nerves and vital structures such as the brainstem. Variations in the mutation determine the nature of the tumor's development. The only environmental exposure that has been definitely associated with the growth of a VS is therapeutic radiation exposure to the head.[9][10][11][12]

Unilateral Vestibular Schwannoma
  1. ^ "Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis". NIDCD. 18 August 2015. Retrieved 13 August 2017.
  2. ^ "Acoustic Neuroma". NORD. Retrieved 16 July 2018.
  3. ^ a b Stangerup SE, Caye-Thomasen P, Tos M, Thomsen J (June 2006). "The natural history of vestibular schwannoma". Otology & Neurotology. 27 (4): 547–552. doi:10.1097/01.mao.0000217356.73463.e7. PMID 16791048. S2CID 18874879.
  4. ^ a b Graffeo C (2019). "Chapter 6: Disease Presentation of Sporadic Vestibular Schwannoma". In Carlson ML, Link MJ, Driscoll CL, et al. (eds.). Comprehensive Management of Vestibular Schwannoma. New York: Thieme. ISBN 978-1-62623-332-4.
  5. ^ Sweeney A, Breen JT, Vrabec JT (2019). "Chapter 29: Training in Vestibular Schwannoma Surgery". In Carlson ML, Link MJ, Driscoll CL, et al. (eds.). Comprehensive Management of Vestibular Schwannoma. New York. ISBN 978-1-62623-332-4.
  6. ^ "Health Information, Neurofibromatosis Fact Sheet". The National Institute of Neurological Disorders and Stroke (NINDS).
  7. ^ Lloyd SK, Evans DG (2019). "Chapter 78: Genetics of Neurofibromatosis Type 2". In Carlson ML, Link MJ, Driscoll CL, et al. (eds.). Comprehensive Management of Vestibular Schwannoma. New York: Thieme. ISBN 978-1-62623-332-4.
  8. ^ Kluwe L, Mautner V, Heinrich B, Dezube R, Jacoby LB, Friedrich RE, MacCollin M (February 2003). "Molecular study of frequency of mosaicism in neurofibromatosis 2 patients with bilateral vestibular schwannomas". Journal of Medical Genetics. 40 (2): 109–114. doi:10.1136/jmg.40.2.109. PMC 1735360. PMID 12566519.
  9. ^ Gupta, Vinay Kumar; Thakker, Arjuna; Gupta, Keshav Kumar (December 2020). "Vestibular Schwannoma: What We Know and Where We are Heading". Head and Neck Pathology. 14 (4): 1058–1066. doi:10.1007/s12105-020-01155-x. ISSN 1936-0568. PMC 7669921. PMID 32232723.
  10. ^ "Health Information, Vestibular Schwannoma (Acoustic Neuroma)". National Institute on Deafness and Other Communication Disorders (NIDCD). 6 March 2017.
  11. ^ Acoustic Neuroma Basic Overview, Patient Information Booklet. Acoustic Neuroma Association. May 2018. p. 18. Archived from the original on 2021-12-29. Retrieved 2021-12-29.
  12. ^ Carlson ML, ed. (2019). Comprehensive Management of Vestibular Schwannoma. Thieme.