Malignant peripheral nerve sheath tumour

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Malignant peripheral nerve sheath tumour
Diagnosis in short

MPNST. H&E stain.

LM spindle cell lesion (or very rarely epithelioid lesion) with nuclear atypia, mitotic activity, +/-herring bone pattern
Subtypes malignant triton tumour
LM DDx synovial sarcoma, fibrosarcoma, cellular schwannoma, plexiform schwannoma
Site soft tissue

Associated Dx neurofibroma, plexiform neurofibroma
Syndromes neurofibromatosis type 1

Signs mass
Prognosis poor

Malignant peripheral nerve sheath tumour, abbreviated MPNST, is an uncommon malignant tumour of the nerve sheath.

It is also known neurofibrosarcoma[1], neurogenic sarcoma.[2] and malignant schwannoma - these terms are however depreceated.[3]

General

  • Malignant - as the name implies.
  • Usually assoc. with a peripheral nerve.[4]
  • May be seen in the context of neurofibromatosis type 1 or radiation induced.[5]
  • Approx 50-70% arise from (mostly plexiform) neurofibromas.
  • Usu. adults
  • Approx. 5% of all malignant soft tissue lesions.

Microscopic

Features:[6]

  • Cellular - usu. spindle cells.
    • Very rarely epithelioid.[7]
  • Nuclear atypia.
  • Mitoses.
  • +/-Herring bone pattern.
  • Perivascular hypercellularity.
  • Tumor herniation into vascular lumens.
  • "Pseudocapsule" with tumour invasion of adjacent tissue.

Notes:

  • May be diagnosed in a poorly diff. tumour if patient has NF1.

DDx:

DDx of herring bone:

Images

www:

Grading

  • Can be graded histologically, according WHO[8] and this is prognostic.[9]
  • grade IV: Presence of necrosis (3/4 of all MPNST).
  • grade III: Mitotic count exceeds 4/1 HPF.
  • grade II: nuclear size (<3x of neurofibroma cell), hyperchromatic nuclei.
    • overlap with cellular ("atypical") neurofibroma (DDx).


Sarcoma grading system[10] - based on:

  • Tumour differentiation.
  • Mitotic rate.
  • Necrosis.

IHC

Features:[11]

  • S-100 +ve ~ 30% of tumours.
  • SOX10 +ve ~ 50% of tumours.
  • Neurofibromin (NFC) -ve (88% in NF1, 43% sporadic MPNST)[12]
  • MIB-1 ≥20% is highly predictive of malignant peripheral nerve sheath tumor (87% sensitivity and 96% specificity).[13]


Others:[8]

  • p53.
  • p16 -ve.
  • p27.
  • p75NTR +ve (80%).

Molecular

Features:[14][15]

  • Atypical neurofibromas and low-grade MPNST have a common methylation profile and frequent losses of CDKN2A.
  • A subset of MPNST show loss of trimethylation of histone H3 at lysine 27 (H3K27me3).
  • P53 and beta-spectrin mutations during progression reported.

See also

References

  1. 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.
  2. Sham, ME.; Ghorpade, A.; Shetty, S.; Hari, .; Vinay, . (Mar 2010). "Malignant peripheral nerve cell tumour.". J Maxillofac Oral Surg 9 (1): 68-71. doi:10.1007/s12663-010-0019-6. PMID 23139572.
  3. {WHOCNS2007}
  4. {WHOCNS2007}
  5. Ducatman, BS.; Scheithauer, BW.; Piepgras, DG.; Reiman, HM.; Ilstrup, DM. (May 1986). "Malignant peripheral nerve sheath tumors. A clinicopathologic study of 120 cases.". Cancer 57 (10): 2006-21. PMID 3082508.
  6. Pekmezci, M.; Reuss, DE.; Hirbe, AC.; Dahiya, S.; Gutmann, DH.; von Deimling, A.; Horvai, AE.; Perry, A. (Feb 2015). "Morphologic and immunohistochemical features of malignant peripheral nerve sheath tumors and cellular schwannomas.". Mod Pathol 28 (2): 187-200. doi:10.1038/modpathol.2014.109. PMID 25189642.
  7. Carter, JM.; O'Hara, C.; Dundas, G.; Gilchrist, D.; Collins, MS.; Eaton, K.; Judkins, AR.; Biegel, JA. et al. (Jan 2012). "Epithelioid malignant peripheral nerve sheath tumor arising in a schwannoma, in a patient with neuroblastoma-like schwannomatosis and a novel germline SMARCB1 mutation.". Am J Surg Pathol 36 (1): 154-60. doi:10.1097/PAS.0b013e3182380802. PMID 22082606.
  8. 8.0 8.1 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.
  9. 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/.
  10. 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.
  11. 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.
  12. Reuss, DE.; Habel, A.; Hagenlocher, C.; Mucha, J.; Ackermann, U.; Tessmer, C.; Meyer, J.; Capper, D. et al. (Apr 2014). "Neurofibromin specific antibody differentiates malignant peripheral nerve sheath tumors (MPNST) from other spindle cell neoplasms.". Acta Neuropathol 127 (4): 565-72. doi:10.1007/s00401-014-1246-6. PMID 24464231.
  13. Pekmezci, M.; Reuss, DE.; Hirbe, AC.; Dahiya, S.; Gutmann, DH.; von Deimling, A.; Horvai, AE.; Perry, A. (Feb 2015). "Morphologic and immunohistochemical features of malignant peripheral nerve sheath tumors and cellular schwannomas.". Mod Pathol 28 (2): 187-200. doi:10.1038/modpathol.2014.109. PMID 25189642.
  14. Röhrich, M.; Koelsche, C.; Schrimpf, D.; Capper, D.; Sahm, F.; Kratz, A.; Reuss, J.; Hovestadt, V. et al. (Feb 2016). "Methylation-based classification of benign and malignant peripheral nerve sheath tumors.". Acta Neuropathol. doi:10.1007/s00401-016-1540-6. PMID 26857854.
  15. Hirbe, AC.; Dahiya, S.; Miller, CA.; Li, T.; Fulton, RS.; Zhang, X.; McDonald, S.; DeSchryver, K. et al. (Sep 2015). "Whole Exome Sequencing Reveals the Order of Genetic Changes during Malignant Transformation and Metastasis in a Single Patient with NF1-plexiform Neurofibroma.". Clin Cancer Res 21 (18): 4201-11. doi:10.1158/1078-0432.CCR-14-3049. PMID 25925892.