"low ADC values (lower than normal cerebellum, e.g. ~550 x 10-6 mm2/s) 11"
"low ADC values (lower than normal cerebellum, e.g. ~550 x 10-6 mm2/s) 11"
"In the 2016 edition of the WHO classification of CNS tumours, four molecular groups were recognised (WNT, SHH, group 3 and group 4)."
"In the 2016 edition of the WHO classification of CNS tumours, four molecular groups were recognised (WNT, SHH, group 3 and group 4)."
"medulloblastoma, WNT-activated"
"medulloblastoma, SHH-activated"
"non-WNT/non-SHH, further divided into:"
"non-WNT/non-SHH, further divided into:"
"* Note: in CBTRUS statistical reports "gliomas, malignant NOS" are more common, however, they include a variety of incompletely classified tumours 19,20."
"WNT (~10%)"
"SHH-activated TP53-wildtype (~20%)"
"SHH-activated TP53-mutant (~10%)"
"Although the prognosis of medulloblastomas is variable, with some molecular groups (e.g. WNT-activated) having a very high cure rate with appropriate therapy, all medulloblastomas are, at least for now, considered grade 4 tumours 17."
"Overall, the vast majority (94%) of medulloblastomas arise in the cerebellum, and the majority of these arise from the vermis (75%). They tend to protrude into the fourth ventricle from its roof (superior medullary velum), and may even grow directly into the brainstem 1,7. This pattern is particularly common in group 3 and group 4 and in some SHH-activated tumours 10."
"Other areas are less common and are seen more frequently in older children and adults. In such cases, the tumour is also more likely to be poorly marginated and demonstrate larger cyst formation 7. Adult medulloblastomas are usually located laterally, in the cerebellar hemispheres, with only 28% centred in the vermis; these are most commonly of the SHH-activated tumours 10."
"The cerebellar peduncle epicentre is almost exclusively seen in WNT-activated tumours 8-10."
"WNT-activated tumours tend to vividly enhance 17"
"decreased NAA"
"very likely WNT-activated tumours and therefore the best prognosis"
"very likely SHH subgroup and therefore intermediate prognosis"
"may be group 3, group 4 or SHH"
"typically infants with a tumour with ill-defined margins but prominent enhancement: likely group 3 (or SHH) and therefore worst prognosis"
"adults with variably defined and variably enhancing tumours: most likely SHH; haemorrhage raises the probability of group 4 13"
"SHH"
"WNT: very good"
"SHH: infants good, others intermediate"
Expected headings
"Grading"
"Predicting molecular subgroup from imaging"
"Complications"
"Other areas are less common and are seen more frequently in older children and adults. In such cases, the tumour is also more likely to be poorly marginated and demonstrate larger cyst formation 7. Adult medulloblastomas are usually located laterally, in the cerebellar hemispheres, with only 28% centred in the vermis; these are most commonly of the SHH-activated tumours 10."
"adults with variably defined and variably enhancing tumours: most likely SHH; haemorrhage raises the probability of group 4 13"
"Traditionally, and still relevant in addition to molecular characteristics, prognosis is considered poor if young age at diagnosis (1.5 cm3 residual), and presence of CSF metastases at the time of diagnosis; common in infants and children (~25%) and uncommon in adults (~2%) 1,12."
"Molecular subgroups, histology, location, appearance, and demographics all interact, but notwithstanding this, some fairly robust predictions can be made based on imaging when taken together 10,17. Location is the key to this approach."
"In 1925, Bailey and Cushing described the first cases of medulloblastomas 1."