Schwannoma pathophysiology: Difference between revisions
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==Pathophysiology== | ==Pathophysiology== | ||
=== | * Unilateral schwannomas are usually sporadic. | ||
* Bilateral schwannomas are associated with Neurofibromatosis type 2. | |||
** Allelic inactivation of NF2 gene involving a point mutation or multiexon deletion in second point mutation or loss of heterozygosity. <ref name="pmid20729918">{{cite journal |vauthors=Hadfield KD, Smith MJ, Urquhart JE, Wallace AJ, Bowers NL, King AT, Rutherford SA, Trump D, Newman WG, Evans DG |title=Rates of loss of heterozygosity and mitotic recombination in NF2 schwannomas, sporadic vestibular schwannomas and schwannomatosis schwannomas |journal=Oncogene |volume=29 |issue=47 |pages=6216–21 |date=November 2010 |pmid=20729918 |doi=10.1038/onc.2010.363 |url=}}</ref> | |||
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# Direct genetic change involving the ''NF2'' gene on chromosome 22 | # Direct genetic change involving the ''NF2'' gene on chromosome 22 | ||
# | # Secondary to merlin inactivation <ref name="pmid25893302">{{cite journal |vauthors=Petrilli AM, Fernández-Valle C |title=Role of Merlin/NF2 inactivation in tumor biology |journal=Oncogene |volume=35 |issue=5 |pages=537–48 |date=February 2016 |pmid=25893302 |pmc=4615258 |doi=10.1038/onc.2015.125 |url=}}</ref><br /> | ||
==Associated Conditions== | ==Associated Conditions== | ||
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==Gross and Microscopic Pathology== | ==Gross and Microscopic Pathology== | ||
==== Microscopic appearance ==== | ==== Microscopic appearance ==== | ||
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*Antoni type B pattern cells are less compact and are prone to cystic degeneration. | *Antoni type B pattern cells are less compact and are prone to cystic degeneration. | ||
===== Variants ===== | ===== Variants ===== | ||
Schwannoma variants include 6,8: | Schwannoma variants include 6,8: | ||
Revision as of 23:50, 27 October 2019
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: ; Maneesha Nandimandalam, M.B.B.S.[2]
Overview
Pathophysiology
- Unilateral schwannomas are usually sporadic.
- Bilateral schwannomas are associated with Neurofibromatosis type 2.
- Allelic inactivation of NF2 gene involving a point mutation or multiexon deletion in second point mutation or loss of heterozygosity. [1]
Genetics
- Loss of function of a tumor suppressor gene called merlin gene, either by:
- Direct genetic change involving the NF2 gene on chromosome 22
- Secondary to merlin inactivation [2]
Associated Conditions
- Neurofibromatosis type 2 (NF2)[3]
- Schwannomatosis
- Carney's complex
Gross and Microscopic Pathology
Microscopic appearance
- Conventional schwannomas are composed of spindle cells which demonstrate two growth patterns: Antoni type A and Antoni type B 7,8.[4][5][6]
- Antoni type A pattern: elongated cells are densely packed and arranged in fascicles. Palisades are sometimes seen; when prominent these form Verocay bodies.
- Antoni type B pattern cells are less compact and are prone to cystic degeneration.
Variants
Schwannoma variants include 6,8:
- ancient schwannoma
- cellular schwannoma
- predominantly composed of Antoni A tissue
- no Verocay bodies
- most commonly found in a paravertebral location, or trigeminal nerves (CN V)
- melanotic schwannoma: dense melanin pigment
- plexiform schwannoma[7]
- usually arise from skin or subcutaneous tissues
- usually diagnosed at birth or childhood
- usually sporadic, but rarely associated with NF2
- should not be confused with plexiform neurofibromas
- associated with NF1
- may undergo malignant change
Immunohistochemistry
References
- ↑ Hadfield KD, Smith MJ, Urquhart JE, Wallace AJ, Bowers NL, King AT, Rutherford SA, Trump D, Newman WG, Evans DG (November 2010). "Rates of loss of heterozygosity and mitotic recombination in NF2 schwannomas, sporadic vestibular schwannomas and schwannomatosis schwannomas". Oncogene. 29 (47): 6216–21. doi:10.1038/onc.2010.363. PMID 20729918.
- ↑ Petrilli AM, Fernández-Valle C (February 2016). "Role of Merlin/NF2 inactivation in tumor biology". Oncogene. 35 (5): 537–48. doi:10.1038/onc.2015.125. PMC 4615258. PMID 25893302.
- ↑ Hilton DA, Hanemann CO (April 2014). "Schwannomas and their pathogenesis". Brain Pathol. 24 (3): 205–20. doi:10.1111/bpa.12125. PMID 24450866.
- ↑ Doddrell RD, Dun XP, Shivane A, Feltri ML, Wrabetz L, Wegner M; et al. (2013). "Loss of SOX10 function contributes to the phenotype of human Merlin-null schwannoma cells". Brain. 136 (Pt 2): 549–63. doi:10.1093/brain/aws353. PMC 3572932. PMID 23413263.
- ↑ Sayed SI, Rane P, Deshmukh A, Chaukar D, Menon S, Arya S; et al. (2012). "Ancient schwannoma of the parapharynx causing dysphagia: a rare entity". Ann R Coll Surg Engl. 94 (7): e217–20. doi:10.1308/003588412X13373405385737. PMC 3954264. PMID 23031754.
- ↑ Giovannini M, Bonne NX, Vitte J, Chareyre F, Tanaka K, Adams R; et al. (2014). "mTORC1 inhibition delays growth of neurofibromatosis type 2 schwannoma". Neuro Oncol. 16 (4): 493–504. doi:10.1093/neuonc/not242. PMC 3956353. PMID 24414536.
- ↑ Tchernev G, Chokoeva AA, Patterson JW, Bakardzhiev I, Wollina U, Tana C (February 2016). "Plexiform Neurofibroma: A Case Report". Medicine (Baltimore). 95 (6): e2663. doi:10.1097/MD.0000000000002663. PMC 4753888. PMID 26871793.