Peripheral nerve sheath tumours
Peripheral nerve sheath tumours, abbreviated PNSTs, are common in neuropathology and occasionally show-up elsewhere. A very common PNST is the schwannoma.
Classification
A classification:[1]
- Benign:
- Schwannoma.
- Neurofibroma.
- Perineurioma.
- Traumatic neuroma.
- Malignant:
- Malignant peripheral nerve sheath tumour (MPNST).
Schwannoma
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 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.
Images:
- Antoni A (pathguy.com).
- Antoni A & Antoni B side-by-side (ajnr.org).
- Psammomatous melanotic schwannoma - high mag. (WC).
Subtypes
There are four:[4]
- Conventional.
- Most common.
- Cellular.
- May mimic MPNST.
- Plexiform.
- May mimic MPNST if cellular - esp. in childhood.
- Melanotic.
- May be confused with melanoma.
- Psammomatous form (psammomatous melanotic schwannoma) associated with a heritable disorder (Carney complex).
Notes:
- Carney complex:[4]
- Cutaneous lentigines.
- Myxomas (skin (subcutaneous), subcutanous, heart).
- Endocrine neoplasms.
IHC
Features:[5]
- S-100 +ve.
- Glut1 +ve.
- CD34 +ve.
- Cytokeratins ~70% +ve.[citation needed]
- SOX10 +ve.[6]
- -ve in synovial sarcoma, rhabdomyosarcoma, chondrosarcoma.
Perineurioma
General
- Benign tumour derived from perineurial cells.
Microscopic
Features:[7]
- Long slender spindle cells with:
- Small spindle-shaped nuclei.
DDx:
- Neuroma.
- Neurofibroma.
- Schwannoma.
Image:
IHC
Features:[7]
- S100 -ve.
- EMA +ve.
Traumatic neuroma
General
- Consequence of trauma -- diagnosis requires history of trauma.
Microscopic
Features:
- Nerve with adjacent small organized micro-fascicles in collagen - as seen in regeneration.
Palisaded encapsulated neuroma
- Abbreviated PEN.
- AKA palisaded and encapsulated neuroma.
General
- Flesh-colour papule - classically on the face.[8]
- Isolated finding - not associated with a systemic disease or malignancy.[9]
- Superficial skin.[10]
Microscopic
Features:[8]
- Encapsulated dermal spindle cell lesion.
- Fasciular arrangement.
- Neural-type spindle cells:
- Not vacuolated.
- Nuclei have pointy ends.
- Intralesional clefts.
- Useful to differentiate from schwannoma.
DDx:
- Schwannoma:[8]
- No intralesional clefts.
- More variability in the cellularity.
- May be deep.
Other considerations:
- Leiomyoma - cytoplasm not vacuolated, nuclei more elliptical.
Images:
IHC
Features:[9]
- S100 +ve.
- EMA +ve (capsule of lesion).
Neurofibroma
General
- May be a part of neurofibromatosis 1 (NF1).
- Composed of Schwann cells, axons, fibrous material.[1]
Classification:[11]
- Localized - sporatic.
- Diffuse - usu. poorly defined, young adults and children; sporatic.
- Plexiform - assoc. with NF1.
Gross/radiologic
Gross features (plexiform NF):[11]
- "Bag of worms" appearance.
Radiologic:[11]
- Fusiform mass.
Microscopic
Features:
- Spindle cells with wavy nuclei without pleomorphism - key feature.
- May be arranged in fascicles and intermixed with collagen.
- Often no pattern is apparent.
- Moderate increase of cellularity vis-a-vis normal dermis. (???)
- May be poorly or well-circumscribed.
- +/-Plexiform growth pattern - "bag of worms".[1]
- Mast cells[12] - one has to look for them at high power.
DDx:
- Schwannoma.
- Dermatofibrosarcoma protuberans (DFSP) - S-100 -ve, CD34 +ve.
- Ganglioneuroma.
Images:
- WC:
- www:
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IHC
Features:[5]
- S100 +ve.
- CD34 +ve.
- Glut1 +ve.
- EMA +ve/-ve.
Neurothekeoma
General
- Rare.
- Female > male.
Microscopic
Features:[13]
- Superficial dermal lesion:
- Usu. lobulated or micronodular architecture - key feature.
- +/-Focal sheeting.
- Spindle/epithelioid morphology with pale eosinophilic cytoplasm - key feature.
- +/-Inflammation around lesion.
- +/-Surrounded by collagen.
- Usu. lobulated or micronodular architecture - key feature.
Notes:
- No atypia.
- Mitoses rare/none.
- Often poorly circumscribed.
Subtypes:[14]
- Cellular.
- Myxoid.
- Intermediate.
DDx:
- Dermatofibroma.
- Angiomatoid fibrous histiocytoma -- have cystic blood filled spaces, inflammation.[15]
Image(s):
IHC
Features:[13]
- NKI/C3 (AKA NKI-C3) +ve.
- NSE +/-ve.
Others:[16]
- Vimentin +ve.
- CD10 +ve.
- Microphthalmia transcription factor +ve.
- PGP9.5 +ve.
Exclusionary:
- S100 -ve.
- Exclude other peripheral nerve sheath tumours. (???)
Malignant peripheral nerve sheath tumour
General
- Malignant - as the name implies.
- Usu. assoc. with a peripheral nerve.[citation needed]
- May be seen in the context of neurofibromatosis type 1.
Microscopic
Features:
- Cellular.
- Nuclear atypia.
- Mitoses.
DDx:
- Cellular schwannoma.
- Plexiform schwannoma.
Image(s):
Notes:
- May be diagnosed in a poorly diff. tumour if patient has NF1.
Grading
Sarcoma grading system[20] - based on:
- Tumour differentiation.
- Mitotic rate.
- Necrosis.
IHC
Features:[6]
- S-100 +ve ~ 30% of tumours.
- SOX10 +ve ~ 50% of tumours.
Others:[18]
- p53.
- p16.
- p27.
- MIB-1.
See also
References
- ↑ 1.0 1.1 1.2 1.3 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.
- ↑ 4.0 4.1 Kurtkaya-Yapicier O, Scheithauer B, Woodruff JM (July 2003). "The pathobiologic spectrum of Schwannomas". Histol. Histopathol. 18 (3): 925–34. PMID 12792904.
- ↑ 5.0 5.1 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.
- ↑ 6.0 6.1 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.
- ↑ 7.0 7.1 URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970452-1. Accessed on: 13 May 2011.
- ↑ 8.0 8.1 8.2 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 536. ISBN 978-0443066542.
- ↑ 9.0 9.1 9.2 Newman, MD.; Milgraum, S. (2008). "Palisaded encapsulated neuroma (PEN): an often misdiagnosed neural tumor.". Dermatol Online J 14 (7): 12. PMID 18718196.
- ↑ S. Sade. 8 September 2011.
- ↑ 11.0 11.1 11.2 Wilkinson, LM.; Manson, D.; Smith, CR. (Oct 2004). "Best cases from the AFIP: plexiform neurofibroma of the bladder.". Radiographics 24 Suppl 1: S237-42. doi:10.1148/rg.24si035170. PMID 15486243.
- ↑ Staser, K.; Yang, FC.; Clapp, DW. (Jul 2010). "Mast cells and the neurofibroma microenvironment.". Blood 116 (2): 157-64. doi:10.1182/blood-2009-09-242875. PMID 20233971.
- ↑ 13.0 13.1 Hornick JL, Fletcher CD (March 2007). "Cellular neurothekeoma: detailed characterization in a series of 133 cases". Am. J. Surg. Pathol. 31 (3): 329–40. doi:10.1097/01.pas.0000213360.03133.89. PMID 17325474.
- ↑ Wang AR, May D, Bourne P, Scott G (November 1999). "PGP9.5: a marker for cellular neurothekeoma". Am. J. Surg. Pathol. 23 (11): 1401–7. PMID 10555009.
- ↑ URL: http://surgpathcriteria.stanford.edu/softfib/angiomatoid_fibrous_histiocytoma/. Accessed on: 11 May 2011.
- ↑ Fetsch JF, Laskin WB, Hallman JR, Lupton GP, Miettinen M (July 2007). "Neurothekeoma: an analysis of 178 tumors with detailed immunohistochemical data and long-term patient follow-up information". Am. J. Surg. Pathol. 31 (7): 1103–14. doi:10.1097/PAS.0b013e31802d96af. PMID 17592278.
- ↑ Mills, AM.; Karamchandani, JR.; Vogel, H.; Longacre, TA. (Mar 2011). "Endocervical fibroblastic malignant peripheral nerve sheath tumor (neurofibrosarcoma): report of a novel entity possibly related to endocervical CD34 fibrocytes.". Am J Surg Pathol 35 (3): 404-12. doi:10.1097/PAS.0b013e318208f72e. PMID 21317712.
- ↑ 18.0 18.1 Zhou H, Coffin CM, Perkins SL, Tripp SR, Liew M, Viskochil DH (October 2003). "Malignant peripheral nerve sheath tumor: a comparison of grade, immunophenotype, and cell cycle/growth activation marker expression in sporadic and neurofibromatosis 1-related lesions". Am. J. Surg. Pathol. 27 (10): 1337–45. PMID 14508395.
- ↑ Kar M, Deo SV, Shukla NK, et al. (2006). "Malignant peripheral nerve sheath tumors (MPNST)--clinicopathological study and treatment outcome of twenty-four cases". World J Surg Oncol 4: 55. doi:10.1186/1477-7819-4-55. PMC 1560134. PMID 16923196. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560134/.
- ↑ Trojani M, Contesso G, Coindre JM, et al. (January 1984). "Soft-tissue sarcomas of adults; study of pathological prognostic variables and definition of a histopathological grading system". Int. J. Cancer 33 (1): 37–42. PMID 6693192.