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.

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".

Image:

Malignant peripheral nerve sheath tumours

General

  • Malignant - as the name implies.

Microscopic

Features:

  • Cellular.
  • Mitoses.

DDx:

  • Cellular schwannoma.
  • Plexiform schwannoma.

Image(s):

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. URL: http://www.sarctrials.org/SARC006MPNST. Accessed on: 5 December 2010.