Schwannoma
Schwannoma is a relatively common peripheral nerve sheath tumour.
| Schwannoma | |
|---|---|
| Diagnosis in short | |
 Schwannoma showing Antoni A and Antoni B areas. HPS stain. | |
|
| |
| LM |
Antoni A areas (cellular, fibrillary, polar, elongated), Antoni B area (pauci-cellular, loose microcystic tissue), Verocay bodies (paucinuclear area surrounded by nuclei), hyaline thickened blood vessels, thick capsule. +/-peripheral lymphoid cuff (esp. GI tract) |
| Subtypes | conventional schwannoma, cellular schwannoma, plexiform schwannoma, melanotic schwannoma |
| LM DDx | meningioma, leiomyoma, GIST, intranodal palisaded myofibroblastoma, MPNST |
| IHC | S-100 +ve, EMA -ve, CD34 +ve |
| Site | soft tissue - peripheral nerve sheath tumours |
|
| |
| Syndromes | neurofibromatosis type 2, Carney complex (psammomatous melanotic schwannoma) |
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| |
| Prevalence | common |
| Prognosis | good |
| Clin. DDx | meningioma - esp. at CP angle |
General
- A common neuropathology tumour that occasionally shows-up elsewhere.
- Tumour of tissue surrounding a nerve.
- Axons adjacent to the tumour are normal... but may be compressed.
- May be a part of neurofibromatosis type 2.
Microscopic
Features:[1]
- Antoni A:
- Cellular.
- 'Fibrillary, polar, elongated'.
- Antoni B:
- Pauci-cellular.
- Loose microcystic tissue.
- Verocay bodies - paucinuclear area surrounded by clusters of nuclei - diagnostic feature.
- Hyaline thickened blood vessels.
- Thick capsule.
- In the GI tract: classically have a peripheral lymphoid cuff.[2]
- +/-Hemosiderin deposition within tumour.
Notes:
- Tumour does not smear well.[3]
- Antoni A: may look somewhat like scattered matchsticks.
DDx:
- Meningioma.
- Intranodal palisaded myofibroblastoma - if surrounded by a rim of lymphoid tissue, i.e. intranodal.
- Leiomyoma.
- Gastrointestinal stromal tumour.
- MPNST - schwannoma with ancient change has no significant mitotic activity.[4]
Images
Schwannoma - Antoni A & B - intermed. mag. (WC)
Scwhannoma - Antoni A & B - very high mag. (WC)
Psammomatous melanotic schwannoma - high mag. (WC)
Nerve root schwannoma - intermed. mag. (WC)
www:
- Antoni A (pathguy.com).
- Antoni A & Antoni B side-by-side (ajnr.org).
- Cystic schwannoma - several images (upmc.edu).
Schwannoma subtypes
There are four:[5]
- Conventional schwannoma.
- Cellular schwannoma.
- Plexiform schwannoma.
- Melanotic schwannoma.
Conventional schwannoma
- Most common.
Cellular schwannoma
- May mimic MPNST.
Images:
Plexiform schwannoma
- May mimic MPNST if cellular - esp. in childhood.
Images:
Plexiform schwannoma - low mag. (WC)
Plexiform schwannoma - high mag. (WC)
Melanotic schwannoma
- May be confused with melanoma.
- Psammomatous form (psammomatous melanotic schwannoma) associated with a heritable disorder (Carney complex).
Note:
- Carney complex:[5]
- Cutaneous lentigines.
- Myxomas (skin (subcutaneous), subcutanous, heart).
- Endocrine neoplasms.
Images:
IHC
Features:[6]
- S-100 +ve.
- Glut1 +ve.
- CD34 +ve.
- Cytokeratins ~70% +ve.[citation needed]
- SOX10 +ve.[7]
- -ve in synovial sarcoma, rhabdomyosarcoma, chondrosarcoma.
- EMA -ve. (???)
- Usually +ve (~75% of the time) in meningiomas.[8]
See also
References
- ↑ Wippold FJ, Lubner M, Perrin RJ, Lämmle M, Perry A (October 2007). "Neuropathology for the neuroradiologist: Antoni A and Antoni B tissue patterns". AJNR Am J Neuroradiol 28 (9): 1633–8. doi:10.3174/ajnr.A0682. PMID 17893219. http://www.ajnr.org/cgi/reprint/28/9/1633.
- ↑ Levy AD, Quiles AM, Miettinen M, Sobin LH (March 2005). "Gastrointestinal schwannomas: CT features with clinicopathologic correlation". AJR Am J Roentgenol 184 (3): 797–802. PMID 15728600. http://www.ajronline.org/cgi/content/full/184/3/797.
- ↑ MUN. 24 November 2010.
- ↑ Chan, PT.; Tripathi, S.; Low, SE.; Robinson, LQ. (2007). "Case report--ancient schwannoma of the scrotum.". BMC Urol 7: 1. doi:10.1186/1471-2490-7-1. PMID 17244372.
- ↑ 5.0 5.1 Kurtkaya-Yapicier O, Scheithauer B, Woodruff JM (July 2003). "The pathobiologic spectrum of Schwannomas". Histol. Histopathol. 18 (3): 925–34. PMID 12792904.
- ↑ Hirose T, Tani T, Shimada T, Ishizawa K, Shimada S, Sano T (April 2003). "Immunohistochemical demonstration of EMA/Glut1-positive perineurial cells and CD34-positive fibroblastic cells in peripheral nerve sheath tumors". Mod. Pathol. 16 (4): 293–8. doi:10.1097/01.MP.0000062654.83617.B7. PMID 12692193. http://www.nature.com/modpathol/journal/v16/n4/full/3880761a.html.
- ↑ Nonaka D, Chiriboga L, Rubin BP (September 2008). "Sox10: a pan-schwannian and melanocytic marker". Am. J. Surg. Pathol. 32 (9): 1291–8. doi:10.1097/PAS.0b013e3181658c14. PMID 18636017.
- ↑ Rushing, EJ.; Bouffard, JP.; McCall, S.; Olsen, C.; Mena, H.; Sandberg, GD.; Thompson, LD. (Jun 2009). "Primary extracranial meningiomas: an analysis of 146 cases.". Head Neck Pathol 3 (2): 116-30. doi:10.1007/s12105-009-0118-1. PMID 19644540.