Difference between revisions of "Pilocytic astrocytoma"
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* Alteration usually associated with the MAPK pathway. | * Alteration usually associated with the MAPK pathway. | ||
* KIAA1549-BRAF fusion transcripts most common in sporadic PA. | * KIAA1549-BRAF fusion transcripts most common in sporadic PA. | ||
* Rarely BRAF mutations, SRGAP3-RAF1 or FAM131B-BRAF fusions. | * Rarely BRAF, KRAS or FGFR1 mutations, NTRK2, SRGAP3-RAF1 or FAM131B-BRAF fusions.<ref>{{Cite journal | last1 = Jones | first1 = DT. | last2 = Hutter | first2 = B. | last3 = Jäger | first3 = N. | last4 = Korshunov | first4 = A. | last5 = Kool | first5 = M. | last6 = Warnatz | first6 = HJ. | last7 = Zichner | first7 = T. | last8 = Lambert | first8 = SR. | last9 = Ryzhova | first9 = M. | title = Recurrent somatic alterations of FGFR1 and NTRK2 in pilocytic astrocytoma. | journal = Nat Genet | volume = 45 | issue = 8 | pages = 927-32 | month = Aug | year = 2013 | doi = 10.1038/ng.2682 | PMID = 23817572 }}</ref><ref>{{Cite journal | last1 = Cin | first1 = H. | last2 = Meyer | first2 = C. | last3 = Herr | first3 = R. | last4 = Janzarik | first4 = WG. | last5 = Lambert | first5 = S. | last6 = Jones | first6 = DT. | last7 = Jacob | first7 = K. | last8 = Benner | first8 = A. | last9 = Witt | first9 = H. | title = Oncogenic FAM131B-BRAF fusion resulting from 7q34 deletion comprises an alternative mechanism of MAPK pathway activation in pilocytic astrocytoma. | journal = Acta Neuropathol | volume = 121 | issue = 6 | pages = 763-74 | month = Jun | year = 2011 | doi = 10.1007/s00401-011-0817-z | PMID = 21424530 }}</ref> | ||
==See also== | ==See also== | ||
Revision as of 12:57, 10 July 2015
| Pilocytic astrocytoma | |
|---|---|
| Diagnosis in short | |
 Pilocytic astrocytoma. Smear. H&E stain. | |
| LM DDx | piloid gliosis, oligodendroglioma, glioblastoma |
| Stains | PAS-D +ve (eosinophilic granular bodies) |
| IHC | GFAP +ve |
| Gross | usually cerebellar +/-cystic |
| Site | brain - usu. cerebellum |
|
| |
| Prevalence | common - esp. in children |
| Prognosis | good (WHO Grade I) |
Pilocytic astrocytoma, abbreviated PA, is a low-grade astrocytoma. It the most common glioma in children.
General
- Low-grade astrocytoma - WHO Grade I by definition, but rare anaplastic forms have been described.
- Classically in the cerebellum in children; most common glioma in children.[1]
- The optic glioma is associated with neurofibromatosis 1.
- Usually enhances after CM application
Gross
Features:[1]
- Usually well-circumscribed.
- Often cystic with mural nodule.
Microscopic
Features:[2]
- Classically biphasic (though either may be absent):
- Fibrillar.
- Microcystic/loose.
- Hair-like fibres ~ 1 micrometer; pilo- = hair.[3]
- Best seen on smear or with GFAP IHC.
- Rosenthal fibres - key feature.
- May be rare. Not pathognomonic (see below).
- Eosinophilic granular bodies.
- Low cellularity - when compared to medulloblastoma and ependymoma.
Notes:
- +/-Microvascular proliferation.
- +/-Focal necrosis.
- Necrosis with pseudopalisading more likely glioblastoma.
- +/-Mitoses - not significant in the context of the Dx.
DDx (of Rosenthal fibers):[4]
- Chronic reactive gliosis.
- Subependymoma.
- Ganglioglioma.
- Alexander's disease (rare leukodystrophy).
DDx of pilocystic astrocytoma (brief):
- Piloid gliosis (esp. in sellar lesions).
- Oligodendroglioma.
- Glioblastoma (uncommon - but important).
- Tanycytic Ependymoma
- Pilocytic tumor components may be found in Ganglioglioma, DNET, RGNT
Images
Smears
Bipolar cells with hair-like processes - smear - very high mag. (WC)
EGBs - smear. (WC/AFIP)
Rosenthal fibres - smear. (WC/AFIP)
Sections
Rosenthal fibres. (WC)
Occasional pleomorphism. (WC)
Microvascular proliferation. (WC)
www:
- Rosenthal fibre (ouhsc.edu).
- Pilocytic astrocytoma (upmc.edu).
- Pilocytic astrocytoma - another case (upmc.edu).
- Pilocytic astrocytoma - pennies on a plate (upmc.edu).[5]
- Pilocytic astrocytoma (upmc.edu).
Stains
- PAS-D: eosinophilic granular bodies +ve.
IHC
Features:[6]
- GFAP +ve (fibres).
- CD68: may have a significant macrophage component.
- KI-67: may be "high" (~20% ???).
- Olig 2: Usually strongly present.[7]
Molecular
- Alteration usually associated with the MAPK pathway.
- KIAA1549-BRAF fusion transcripts most common in sporadic PA.
- Rarely BRAF, KRAS or FGFR1 mutations, NTRK2, SRGAP3-RAF1 or FAM131B-BRAF fusions.[8][9]
See also
References
- ↑ 1.0 1.1 Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 82. ISBN 978-0443069826.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 82-4. ISBN 978-0443069826.
- ↑ URL: http://dictionary.reference.com/browse/pilo-. Accessed on: 24 November 2010.
- ↑ Munoz D. 9 Mar 2009.
- ↑ URL: http://path.upmc.edu/cases/case195.html. Accessed on: 8 January 2012.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 84. ISBN 978-0443069826.
- ↑ Otero, JJ.; Rowitch, D.; Vandenberg, S. (Sep 2011). "OLIG2 is differentially expressed in pediatric astrocytic and in ependymal neoplasms.". J Neurooncol 104 (2): 423-38. doi:10.1007/s11060-010-0509-x. PMID 21193945.
- ↑ Jones, DT.; Hutter, B.; Jäger, N.; Korshunov, A.; Kool, M.; Warnatz, HJ.; Zichner, T.; Lambert, SR. et al. (Aug 2013). "Recurrent somatic alterations of FGFR1 and NTRK2 in pilocytic astrocytoma.". Nat Genet 45 (8): 927-32. doi:10.1038/ng.2682. PMID 23817572.
- ↑ Cin, H.; Meyer, C.; Herr, R.; Janzarik, WG.; Lambert, S.; Jones, DT.; Jacob, K.; Benner, A. et al. (Jun 2011). "Oncogenic FAM131B-BRAF fusion resulting from 7q34 deletion comprises an alternative mechanism of MAPK pathway activation in pilocytic astrocytoma.". Acta Neuropathol 121 (6): 763-74. doi:10.1007/s00401-011-0817-z. PMID 21424530.