Cerebellar pilocytic astrocytoma [Neurosurgery Wiki]

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====== Cerebellar pilocytic astrocytoma ======

===== Latest news =====


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===== Key concepts =====

● Often [[cyst]]ic, half of these have a [[mural nodule]].

● Usually presents during the second decade of life (ages 10–20 yrs).

● A subtype of [[pilocytic astrocytoma]]. Formerly referred to by the nonspecific and confusing term [[cystic cerebellar astrocytoma]]. 



===== Epidemiology =====

[[Cerebellar pilocytic astrocytoma epidemiology]].


===== Classification =====

==== Children ====

see [[Cerebellar pilocytic astrocytoma in children]].

==== Adult ====

[[Cerebellar pilocytic astrocytoma]]s in [[adult]]s should be treated with macroscopic complete surgical resection whenever possible. If this is achieved, long-term survival rates are excellent, whereas subtotal resection carries a high risk of tumor recurrence. [[Ki67]] is less important prognostically than the extent of initial resection
((Wade A, Hayhurst C, Amato-Watkins A, Lammie A, Leach P. Cerebellar pilocytic
astrocytoma in adults: a management paradigm for a rare tumour. Acta Neurochir
(Wien). 2013 Aug;155(8):1431-5. doi: 10.1007/s00701-013-1790-1. Epub 2013 Jun 22.
PubMed PMID: 23793962.)).

===== Clinical features =====

In the [[posterior fossa tumor]]s, there is predominantly a [[mass effect]] with [[sign]]s of [[raised intracranial pressure]], especially when [[hydrocephalus]] is present. [[Bulbar palsy]] or [[cerebellar syndrome]] may also be present.

===== Diagnosis =====

[[Cerebellar pilocytic astrocytoma diagnosis]].



===== Differential diagnosis =====

[[Cerebellar pilocytic astrocytoma differential diagnosis]].


===== Treatment =====

see [[Cerebellar pilocytic astrocytoma treatment]].





===== Outcome =====
Nine percent of the children in a study underwent repeated surgery due to progressive tumor recurrence, and 15% were treated for persistent hydrocephalus
((Due-Tønnessen BJ, Lundar T, Egge A, Scheie D. Neurosurgical treatment of
low-grade cerebellar astrocytoma in children and adolescents: a single
consecutive institutional series of 100 patients. J Neurosurg Pediatr. 2013
Mar;11(3):245-9. doi: 10.3171/2012.11.PEDS12265. Epub 2012 Dec 14. PubMed PMID:
23240848.)).

The long-term functional outcome of low-grade cerebellar astrocytoma is generally favourable, in the absence of post-operative [[complications]] and [[brainstem]] involvement. No major impact of [[neurological deficit]]s, [[cognitive function]]s and [[emotional disorder]]s on academic achievement and independent functioning was observed
((Ait Khelifa-Gallois N, Laroussinie F, Puget S, Sainte-Rose C, Dellatolas G.
Long-term functional outcome of patients with cerebellar pilocytic astrocytoma
surgically treated in childhood. Brain Inj. 2014 Nov 10:1-8. [Epub ahead of
print] PubMed PMID: 25383654.)).

The good long-term outcomes suggest that it may be appropriate to do incomplete resection rather than risk additional neurological deficit
((Steinbok P, Mangat JS, Kerr JM, Sargent M, Suryaningtyas W, Singhal A,
Cochrane D. Neurological morbidity of surgical resection of pediatric cerebellar 
astrocytomas. Childs Nerv Syst. 2013 Aug;29(8):1269-75. doi:
10.1007/s00381-013-2171-z. Epub 2013 May 29. PubMed PMID: 23715810.)).

There is controversy about whether patients with tumor remaining after surgery should receive radiation therapy. It is also unclear whether only patients with incomplete resection require follow-up and for how long
((Dirven CM, Mooij JJ, Molenaar WM. Cerebellar pilocytic astrocytoma: a treatment protocol based upon analysis of 73 cases and a review of the literature. Childs Nerv Syst. 1997;13:17–23. doi: 10.1007/s003810050033.)).

====Complications====
Acute hemorrhagic presentation in pilocytic astrocytomas (PAs) has become increasingly recognized. This type of presentation poses a clinically emergent situation in those hemorrhages arising in PAs of the cerebellum, the most frequent site, because of the limited capacity of the posterior fossa to compensate for mass effect, predisposing to rapid neurological deterioration.

===Complete resection===
Complete resection of [[cerebellar astrocytoma]] is an important prognostic factor, indicating a more favorable prognosis than subtotal resection. This was also the conclusion of a much larger study by Villarejo et al. who reviewed 203 cases of low-grade cerebellar astrocytoma
((Villarejo F, Diego JMB, Riva AG. Prognosis of cerebellar astrocytoma in children. Childs Nerv Syst. 2008;24:203–210. doi: 10.1007/s00381-007-0449-8.)).

Loh et al., documented that patients with subtotal removal of cerebellar astrocytoma can have arrested tumor growth or spontaneous tumor regression during long-term follow-up. Following partial resection of pediatric cerebellar astrocytoma, they recommend that the patients be followed up a “wait and see” approach with surveillance using MRI. They found that several tumors treated with radiotherapy after surgery had malignant transformation and do not recommend adjuvant radiation treatment for children with cerebellar astrocytoma who have subtotal resection. More research is needed on the prognosis of patients with subtotal resection of cerebellar astrocytoma
((Loh JK, Lieu AS, Chai CY, Hwang SL, Kwan AL, Wang CJ, Howng SL. Arrested
growth and spontaneous tumor regression of partially resected low-grade
cerebellar astrocytomas in children. Childs Nerv Syst. 2013 Nov;29(11):2051-5.
doi: 10.1007/s00381-013-2113-9. Epub 2013 May 1. PubMed PMID: 23632690; PubMed
Central PMCID: PMC3825417.
)).

===Pilomyxoid features and anaplasia===

A subset may behave in a more aggressive fashion and clinically progress despite the use of conventional treatments. Histologic features associated with a more aggressive course include the presence of monomorphous pilomyxoid features (ie, pilomyxoid variant) and anaplasia in the form of brisk mitotic activity with or without necrosis
((Rodriguez FJ, Scheithauer BW, Burger PC, Jenkins S, Giannini C. Anaplasia in pilocytic astrocytoma predicts aggressive behavior. Am J Surg Pathol. 2010;34(2):147–160. )).

===== Case series =====

[[Cerebellar pilocytic astrocytoma case series]].

===== Case reports =====

[[Cerebellar pilocytic astrocytoma case reports]].

===== References =====