"GFAP: positive"
"NFP: negative"
"BRAF V600E-mutant: uncommon 12"
"Like pilocytic astrocytomas, pilomyxoid astrocytomas usually have alterations of the mitogen-activated protein kinase (MAPK) pathway, primarily through BRAF; typically KIAA1549-BRAF fusion gene (79%) 8,10-12. BRAF V600E mutations are described but uncommon (~10%) 11,12."
"Like pilocytic astrocytomas, pilomyxoid astrocytomas usually have alterations of the mitogen-activated protein kinase (MAPK) pathway, primarily through BRAF; typically KIAA1549-BRAF fusion gene (79%) 8,10-12. BRAF V600E mutations are described but uncommon (~10%) 11,12."
"Like pilocytic astrocytomas, pilomyxoid astrocytomas usually have alterations of the mitogen-activated protein kinase (MAPK) pathway, primarily through BRAF; typically KIAA1549-BRAF fusion gene (79%) 8,10-12. BRAF V600E mutations are described but uncommon (~10%) 11,12."
"The total resection of the tumour is the most reliable predictor of a favourable outcome 3,12. In cases where only subtotal resection is possible, or in recurrent disease, novel therapies with inhibitors of BRAF, mTOR, or MEK are being trialed with variable outcomes 12."
"DWI/ADC: usually high ADC values (facilitated diffusion), reflecting its myxoid matrix"
Expected headings
"Grading"
"Microscopic features"
"Pilomyxoid astrocytomas are usually encountered in young children and infants (mean age of 10-18 months); however, adult cases have been described 3,4,7. Because most of these tumours have been classified as pilocytic astrocytomas, it is uncertain whether they have a distinctive epidemiology 8. They are believed, however, to account for approximately 2% of all childhood astrocytomas 9."
"Pilomyxoid astrocytomas were originally reported as arising in the hypothalamus or optic chiasm, which is the most common location; however, they may also occur elsewhere within the brain, including the posterior fossa, as well as in the spinal cord 1,8,10."
"Like pilocytic astrocytomas, pilomyxoid astrocytomas usually have alterations of the mitogen-activated protein kinase (MAPK) pathway, primarily through BRAF; typically KIAA1549-BRAF fusion gene (79%) 8,10-12. BRAF V600E mutations are described but uncommon (~10%) 11,12."
"There is no characteristic clinical presentation, and symptoms relate to mass effect and tumour location 1-4. Symptoms related to increased intracranial pressure or parenchymal compression are usually present 1-4."
"Pilomyxoid astrocytomas were originally reported as arising in the hypothalamus or optic chiasm, which is the most common location; however, they may also occur elsewhere within the brain, including the posterior fossa, as well as in the spinal cord 1,8,10."
"Features typically found in pilocytic astrocytomas, such as Rosenthal fibres, eosinophilic granular bodies and calcification, are uncommon or absent in pilomyxoid astrocytomas 3,5,8,12. These tumours also lack the biphasic appearance (dense cellular areas alternating with loose cystic areas) usually present in pilocytic astrocytomas 5,12."