Difference between revisions of "Pilomyxoid astrocytoma"

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(→‎General: Update, dropped tumor grading in WHO 2016)
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*A variant of ''pilocytic astrocytoma''.  
*A variant of ''pilocytic astrocytoma''.  
**Some have suggested it is a unique entity.<ref name=pmid16048293>{{cite journal |author=Komotar RJ, Mocco J, Jones JE, ''et al.'' |title=Pilomyxoid astrocytoma: diagnosis, prognosis, and management |journal=Neurosurg Focus |volume=18 |issue=6A |pages=E7 |year=2005 |month=June |pmid=16048293 |doi= |url=}}</ref>
**Some have suggested it is a unique entity.<ref name=pmid16048293>{{cite journal |author=Komotar RJ, Mocco J, Jones JE, ''et al.'' |title=Pilomyxoid astrocytoma: diagnosis, prognosis, and management |journal=Neurosurg Focus |volume=18 |issue=6A |pages=E7 |year=2005 |month=June |pmid=16048293 |doi= |url=}}</ref>
**Some say the outcome is less good than conventional pilocytic astrocytoma.<ref>{{Cite journal  | last1 = Louis | first1 = DN. | last2 = Perry | first2 = A. | last3 = Reifenberger | first3 = G. | last4 = von Deimling | first4 = A. | last5 = Figarella-Branger | first5 = D. | last6 = Cavenee | first6 = WK. | last7 = Ohgaki | first7 = H. | last8 = Wiestler | first8 = OD. | last9 = Kleihues | first9 = P. | title = The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary. | journal = Acta Neuropathol | volume = 131 | issue = 6 | pages = 803-20 | month = Jun | year = 2016 | doi = 10.1007/s00401-016-1545-1 | PMID = 27157931 }}</ref>
**Tumors may mature to conventional PA over time.<ref>{{Cite journal  | last1 = Kleinschmidt-DeMasters | first1 = BK. | last2 = Donson | first2 = AM. | last3 = Vogel | first3 = H. | last4 = Foreman | first4 = NK. | title = Pilomyxoid Astrocytoma (PMA) Shows Significant Differences in Gene Expression vs. Pilocytic Astrocytoma (PA) and Variable Tendency Toward Maturation to PA. | journal = Brain Pathol | volume = 25 | issue = 4 | pages = 429-40 | month = Jul | year = 2015 | doi = 10.1111/bpa.12239 | PMID = 25521223 }}</ref>
*Childhood or adolescence.
*Childhood or adolescence.


Grading:
Grading:
*''WHO Grade II'' by definition.<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref>
*Currently no WHO grade assigned.<ref>{{Cite journal  | last1 = Louis | first1 = DN. | last2 = Perry | first2 = A. | last3 = Reifenberger | first3 = G. | last4 = von Deimling | first4 = A. | last5 = Figarella-Branger | first5 = D. | last6 = Cavenee | first6 = WK. | last7 = Ohgaki | first7 = H. | last8 = Wiestler | first8 = OD. | last9 = Kleihues | first9 = P. | title = The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary. | journal = Acta Neuropathol | volume = 131 | issue = 6 | pages = 803-20 | month = Jun | year = 2016 | doi = 10.1007/s00401-016-1545-1 | PMID = 27157931 }}</ref>
** From 2007-2016 the tumor was ''WHO Grade II'' by definition.<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref> Grading was dropped until further studies clarify the true behaviour.


==Gross==
==Gross==

Revision as of 13:45, 18 May 2016

Pilomyxoid astrocytoma is a neuropathology tumour related to pilocytic astrocytoma.

General

Features:[1]

  • A variant of pilocytic astrocytoma.
    • Some have suggested it is a unique entity.[2]
    • Some say the outcome is less good than conventional pilocytic astrocytoma.[3]
    • Tumors may mature to conventional PA over time.[4]
  • Childhood or adolescence.

Grading:

  • Currently no WHO grade assigned.[5]
    • From 2007-2016 the tumor was WHO Grade II by definition.[1] Grading was dropped until further studies clarify the true behaviour.

Gross

Features:[1]

  • Classically - hypothalamic location/suprasellar location; may involve the sella turcica.[6]
  • Solid.
  • Well-circumscribed.

Microscopic

Features:[1]

  • Consists of small round/ovoid bland cells in a myxoid stroma.
  • Hair-like fibres ~ 1 micrometer.
    • Often difficult to appreciate on standard (H&E) histologic sections.
  • Usually angiocentric (surround blood vessel) - key feature.

Notes:[1]

  • Rosenthal fibres are absent - key negative.
  • Monophasic (unlike classical pilocytic astrocytomas) - key negative.
  • May rarely have eosinophilic granular bodies.

Images

  • Pilomyxoid astrocytoma. (WC/Marvin 101)

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 86. ISBN 978-0443069826.
  2. ↑ Komotar RJ, Mocco J, Jones JE, et al. (June 2005). "Pilomyxoid astrocytoma: diagnosis, prognosis, and management". Neurosurg Focus 18 (6A): E7. PMID 16048293.
  3. ↑ Louis, DN.; Perry, A.; Reifenberger, G.; von Deimling, A.; Figarella-Branger, D.; Cavenee, WK.; Ohgaki, H.; Wiestler, OD. et al. (Jun 2016). "The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary.". Acta Neuropathol 131 (6): 803-20. doi:10.1007/s00401-016-1545-1. PMID 27157931.
  4. ↑ Kleinschmidt-DeMasters, BK.; Donson, AM.; Vogel, H.; Foreman, NK. (Jul 2015). "Pilomyxoid Astrocytoma (PMA) Shows Significant Differences in Gene Expression vs. Pilocytic Astrocytoma (PA) and Variable Tendency Toward Maturation to PA.". Brain Pathol 25 (4): 429-40. doi:10.1111/bpa.12239. PMID 25521223.
  5. ↑ Louis, DN.; Perry, A.; Reifenberger, G.; von Deimling, A.; Figarella-Branger, D.; Cavenee, WK.; Ohgaki, H.; Wiestler, OD. et al. (Jun 2016). "The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary.". Acta Neuropathol 131 (6): 803-20. doi:10.1007/s00401-016-1545-1. PMID 27157931.
  6. ↑ Alimohamadi M, Bidabadi MS, Ayan Z, Ketabchi E, Amirjamshidi A (December 2009). "Pilomyxoid astrocytoma with involvement of the sella turcica in an adolescent". J Clin Neurosci 16 (12): 1648–9. doi:10.1016/j.jocn.2009.01.035. PMID 19766001.
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