Schwannoma pathophysiology
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
Spontaneous
Genetics
- Loss of function of a tumor suppressor gene called merlin gene, either by:
- Direct genetic change involving the NF2 gene on chromosome 22
- Secondarily to merlin inactivation
Associated Conditions
- Neurofibromatosis type 2 (NF2)[1]
- 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.[2][3][4]
- 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[5]
- 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
Positive for:
- S100
- Collagen IV
- CD34
- Neurofilament protein
- Podoplanin
- Calretinin
- Sox10
Negative for:
- EMA
References
- ↑ 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.