Difference between revisions of "Diffuse astrocytoma"

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(WHO 2016 update)
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* Usually shows progression to [[glioblastoma]] sooner or later.
* Usually shows progression to [[glioblastoma]] sooner or later.


Previously categorized as follows:<ref name=WHOCNS>{{Ref WHOCNS|25}}</ref>
WHO 2016 categorization combines morphology and genetics into following groups:<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>
*Diffuse astrocytoma ICD-O: 9400/3
*Diffuse astrocytoma, IDH-mutant  ICD-O: 9400/3 - most frequent.
**Fibrillary astrocytoma ICD-O: 9420/3 - most frequent
**Gemistocytic astrocytoma, IDH-mutant ICD-O:9411/3
**Gemistocytic astrocytoma ICD-O:9411/3
*Diffuse astrocytoma, IDH-wildtype ICD-O: 9400/3
**Protoplasmatic astrocytoma ICD-O:9410/3 - rare
*Diffuse astrocytoma,NOS ICD-O: 9400/3 - genetic data missing.
Note: This subtyping is no longer in use!
 
''Note:'' Older terminologies included Fibrillary astrocytoma (ICD-O: 9420/3) and Protoplasmatic astrocytoma (ICD-O:9410/3)<ref name=WHOCNS>{{Ref WHOCNS|25}}</ref> This subtyping is no longer in use. These tumors are now classified according their IDH mutation status.


==Radiology/Clinic==
==Radiology/Clinic==
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File:Astrocytoma whoII HE.jpg | Astrocytoma, fibrillary type (WC/jensflorian)
File:Astrocytoma whoII HE.jpg | Astrocytoma, fibrillary type (WC/jensflorian)
File:Neuropathology case II 02.jpg | Astrocytoma, protoplasmatic type (WC/jensflorian)
File:Neuropathology case II 02.jpg | Astrocytoma, protoplasmatic type (WC/jensflorian)
File:Gemistocytic astrocytoma.jpg | Gemistocytic astrocytoma (WC/jensflorian)
</gallery>
</gallery>


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*MIB-1: 0-5% (mean: 2%).
*MIB-1: 0-5% (mean: 2%).
*[[IDH-1]] (R132H)+ve in 60-70%.
*[[IDH-1]] (R132H)+ve in 60-70%.
*[[ATRX]] loss in 70%.
**'Note:'' This antibody does not detect other rare IDH1/2 mutations.
*[[ATRX]] nuclear loss in 70%.


<gallery>
<gallery>
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==Molecular==
==Molecular==
*IDH1 R132- or IDH2 R172-point mutations classify the tumors as Diffuse astrocytoma, IDH-mutant.
*Absence of LOH 1p/19q.
*Absence of LOH 1p/19q.
*Tp53 mutations in approx. 60% (80-90% in gemistocytic, 50% in fibrillary types).
*Tp53 mutations in approx. 60% (80-90% in gemistocytic, 50% in fibrillary types).
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*Reactive astrocytosis.
*Reactive astrocytosis.
*Demyelinisation.
*Demyelinisation.
*[[Anaplastic astrocytoma]]
*[[Anaplastic astrocytoma]] - increased mitotic activity.
*[[Oligoastrocytoma]]  
*[[Oligoastrocytoma]], NOS - esp. when genetic data on IDH and LOH 1p/19q are lacking.
*[[Oligodendroglioma]] - esp. protoplasmatic forms.
*[[Oligodendroglioma]] - esp. protoplasmatic forms. LOH 1p/19q testing required.
*[[SEGA]] - esp. gemistocytic forms.
*[[SEGA]] - esp. gemistocytic forms.



Revision as of 08:14, 19 May 2016

Diffuse astrocytoma (AKA: diffuse, low-grade astrocytoma) is a infiltrating astrocytoma occurring in the CNS white matter.

  • Most common grade II WHO glioma in adults (peaks between 30-40 years).
  • 10-15% of all astrocytomas.
  • Usually shows progression to glioblastoma sooner or later.

WHO 2016 categorization combines morphology and genetics into following groups:[1]

  • Diffuse astrocytoma, IDH-mutant ICD-O: 9400/3 - most frequent.
    • Gemistocytic astrocytoma, IDH-mutant ICD-O:9411/3
  • Diffuse astrocytoma, IDH-wildtype ICD-O: 9400/3
  • Diffuse astrocytoma,NOS ICD-O: 9400/3 - genetic data missing.

Note: Older terminologies included Fibrillary astrocytoma (ICD-O: 9420/3) and Protoplasmatic astrocytoma (ICD-O:9410/3)[2] This subtyping is no longer in use. These tumors are now classified according their IDH mutation status.

Radiology/Clinic

  • Mass effect.
  • Seizures.
  • Neurologic decifit.
  • Usually not contrast-enhanching, T2 bright.

Macroscopy

  • No clear demarcation from white matter
  • May contain larger cysts
  • No necrosis

Histology

Features: [3]

  • Cell density higher than normal brain.
  • Mild to moderate nuclear pleomorphism.
    • Monotony of atypical nuclei and irregular distribution indicates neoplasm.
    • "naked nuclei" without recognizeable processes.
    • No prominent nucleolus.
  • Cytoplasm highly variable (even within the same tumour).
    • In normal CNS the cytoplasm blends within the neuropil.
  • Mitoses absent or very rare.
  • Microcystic spaces of the background (none to extensive).
  • No necrosis, no vascular proliferations.
    • Except radiation necrosis.
  • Lymphocytic cuffing (mostly in gemistocytic type)
  • Abent to few rosenthal fibers.


IHC

  • GFAP+ve.
  • MAP2+ve (especially in cell processes).
  • Vimentin+ve (often perinuclear).
  • S-100+ve.
  • p53: Nuclear staining in 30% of the tumours (usually few cells).
  • MIB-1: 0-5% (mean: 2%).
  • IDH-1 (R132H)+ve in 60-70%.
    • 'Note: This antibody does not detect other rare IDH1/2 mutations.
  • ATRX nuclear loss in 70%.

Molecular

  • IDH1 R132- or IDH2 R172-point mutations classify the tumors as Diffuse astrocytoma, IDH-mutant.
  • Absence of LOH 1p/19q.
  • Tp53 mutations in approx. 60% (80-90% in gemistocytic, 50% in fibrillary types).
  • MGMT promotor methylated in approx. 50%.

DDx


See also

  1. 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.
  2. The International Agency for Research on Cancer (Editors: Louis, D.N.; Ohgaki, H.; Wiestler, O.D.; Cavenee, W.K.) (2007). Pathology and Genetics of Tumours of Tumors of the Central Nervous System (IARC WHO Classification of Tumours) (4th ed.). Lyon: World Health Organization. pp. 25. doi:10.1007/s00401-007-0243-4. ISBN 978-9283224303.
  3. Burger, P.C.; Scheithauer, B.W. (2007). Tumors of the Central Nervous System (Afip Atlas of Tumor Pathology) (4th ed.). Washington: American Registry of Pathology. pp. 34. ISBN 1933477016.