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Start free with EleplanPilocytic astrocytoma
ORPHA:251612Disease
What it is
A rare astrocytoma characterized by bipolar hair-like projections extending from the neoplastic astrocytes, myxoid areas, eosinophilic granular bodies, and Rosenthal fibers. This WHO grade 1 tumor is most often located in the cerebellum in children, or in the hypothalamus, brain stem, optic chiasma, and brain hemispheres in adults. Depending on the primary location and the growth rate of the tumor, patients may present with signs of increased intracranial pressure or focal neurological signs such as decreased visual acuity, ataxia, and/or nystagmus, among other symptoms. Molecularly, it exhibits alterations in genes of the MAPK signaling pathway, most commonly KIAA1549::BRAF fusion.
Key facts
- Prevalence
- 1-9 / 1 000 000 (annual incidence, United States)
- Age of onset
- All ages
- Inheritance
- Not applicable
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Genes reported in subtypes
Orphanet records these genes on 1 more specific entry under this disorder, not on this entry itself:
A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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