Difference between revisions of "Peripheral nerve sheath tumours"

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*May be poorly or well-circumscribed.
*May be poorly or well-circumscribed.
*+/-Plexiform growth pattern - "bag of worms".<ref name=pmid17893219/>
*+/-Plexiform growth pattern - "bag of worms".<ref name=pmid17893219/>
*Mast cells<ref name=pmid20233971>{{Cite journal  | last1 = Staser | first1 = K. | last2 = Yang | first2 = FC. | last3 = Clapp | first3 = DW. | title = Mast cells and the neurofibroma microenvironment. | journal = Blood | volume = 116 | issue = 2 | pages = 157-64 | month = Jul | year = 2010 | doi = 10.1182/blood-2009-09-242875 | PMID = 20233971 }}</ref> - one has to look for them at high power.


DDx:
DDx:

Revision as of 00:45, 4 October 2011

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

Microscopic

Features:[1]

  • Antoni A:
    • Cellular.
    • 'Fibrillary, polar, elongated'.
  • Antoni B:
    • Pauci-cellular.
    • Loose microcystic tissue.
  • Verocay bodies - paucinuclear area surrounded by nuclei.
  • Hyaline thickened blood vessels.
  • In the GI tract: classically have a peripheral lymphoid cuff.[2]

Notes:

  • Tumour does not smear well.[3]
  • Antoni A: may look somewhat like scattered matchsticks.

Micrographs:

Subtypes

There are four:[4]

  1. Conventional.
    • Most common.
  2. Cellular.
  3. Plexiform.
    • May mimic MPNST if cellular - esp. in childhood.
  4. 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]

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:
      1. Not vacuolated.
      2. 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

Classification:[11]

  1. Localized - sporatic.
  2. Diffuse - usu. poorly defined, young adults and children; sporatic.
  3. 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:

Images:

IHC

Features:[5]

  • S100 +ve.
  • CD34 +ve.
  • Glut1 +ve.
  • EMA +ve/-ve.

Neurothekeoma

  • AKA myxoma of the nerve sheath, AKA nerve sheath myxoma.

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.

Notes:

  • No atypia.
  • Mitoses rare/none.
  • Often poorly circumscribed.

Subtypes:[14]

  • Cellular.
  • Myxoid.
  • Intermediate.

DDx:

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

  • AKA neurofibrosarcoma.[17]
  • Commonly abbreviated MPNST.

General

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

  • Can be graded histologically,[18] and this is prognostic.[19]

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. ↑ 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.
  2. ↑ 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.
  3. ↑ MUN. 24 November 2010.
  4. ↑ 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. ↑ 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. ↑ 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. ↑ 7.0 7.1 URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970452-1. Accessed on: 13 May 2011.
  8. ↑ 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. ↑ 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.
  10. ↑ S. Sade. 8 September 2011.
  11. ↑ 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.
  12. ↑ 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. ↑ 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.
  14. ↑ 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.
  15. ↑ URL: http://surgpathcriteria.stanford.edu/softfib/angiomatoid_fibrous_histiocytoma/. Accessed on: 11 May 2011.
  16. ↑ 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.
  17. ↑ 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. ↑ 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.
  19. ↑ 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/.
  20. ↑ 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.
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