Peripheral nerve sheath tumours

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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.
  • 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 associated with a heritable disorder (Carney complex).

Notes:

  • Carney complex:[4]
    • Cutaneous lentigines.
    • Myxomas (skin (subcutaneous), subcutanous, heart).
    • Endocrine neoplasms.

IHC

Features:[5]

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.

Neurofibroma

General

Microscopic

Features:[1]

  • Plexiform growth pattern - "bag of worms".

DDx:

Image:

IHC

Features:[5]

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

Neurothekeoma

General

  • Rare.
  • Female > male.

Microscopic

Features:[7]

  • Dermal spindle cell lesion.
  • +/-Inflammation around lesion.

Notes:

  • No atypia.
  • Mitoses rare/none.

DDx:

Image(s):

IHC

Features:[7]

  • NKI-C3 +ve.
  • NSE +/-ve.

Malignant peripheral nerve sheath tumours

General

  • Malignant - as the name implies.
  • Usu. assoc. with a peripheral nerve.[citation needed]

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,[9] and this is prognostic.[10]

Sarcoma grading system[11] - based on:

  • Tumour differentiation.
  • Mitotic rate.
  • Necrosis.

IHC

Features:[6]

  • S-100 +ve ~ 30% of tumours.
  • SOX10 +ve ~ 50% of tumours.

Others:[9]

  • 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 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.
  8. URL: http://www.sarctrials.org/SARC006MPNST. Accessed on: 5 December 2010.
  9. 9.0 9.1 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.
  10. 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/.
  11. 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.