Pediatric Brain Tumors Flashcards
Your pediatric pt has a brain tumor. Where are you most likely to find it?
Infratentorial (cerebellum and brainstem)
What is the most common pediatric solid tumor?
Brain tumor! Second to all cancer only after Leukemia
What is a PNET?
2nd most common tumor in kids.
It is a SUPRAtentorial medulloblastoma
MC brain tumor in kids?
Astrocytoma (same as for adults, except infratentorial as opposed to hemispheric in adults)
List some genetic aberration that predispose peds pts to brain tumors of certain varieties.
Tuberous Sclerosis Ch.9/16- TSC1/2- Subependymal Giant Cell astrocytoma, Cortical tubers
NF1 Ch. 17- Glioma (optic nerve)
NF2- Ch. 22- bilateral acoustic schwannoma
VHL Ch. 3- hemangioma
Turcott syndrome (APC)- Medulloblastoma + GBM
Cowden (xPTEN= ^mTOR)- dysplastic gangliocytoma in cerebellum
Nevoid basal cell carcinoma/Gorlin synd (Ch. 9 PTCH)- Medulloblastoma
Describe the age classifications of various tumor locations.
11 yo: Supra/Infratentorial (including midline)- glioma, PNET, medulloblastoma, germ cell
Name the different glial tumor types.
Astrocytoma, oligodentrocytoma, ependymoma, choroid plexus tumors, GBM
BEST way to look for tumor?
MRI > CT»_space; Bone scan (for mets)
Kid has a supratentorial tumor. What symptoms do you expect?
Hemiparesis, seizures
Kid has a midline tumor. What symptoms do you expect?
Endocrinopathies- compression of hypothalamus, pituitary
Hydrocephalus- compression of ventricular system (early AM headache, sundowning, bulging fontanelle)
Kid has an infratentorial tumor (MC). What symptoms do you expect?
Increased ICP due to compression of 4th ventricle
—> papilledema (blurring of optic disk margins) first sign, then —> sundowning/bulging fontanelle if delayed intervention
Kid has a brainstem tumor. What symptoms do you expect?
Diplopia, Dysarthria, Dysphagia- due to loss of CNs
Crossed weakness- due to lesion rostral to decussation
Lethargy, v respirations, coma. DON’T FUCK W/ THE BRAINSTEM
In many pediatric tumors, the MAPK pathway is deranged. Some derangements are preferentially found in certain parts of the brain and will this present with certain symptoms. Describe these.
BRAF fusion- Cerebellar tonsils
BRAF v600E- extracerebellar tumors
NF1- optic pathways (remember?! NF1 - optic nerve glioma)
You see hair-like projections radiating from neoplastic cells. What are these called and what type of tumor are they hallmarks of?
Rosenthal fibers, characteristic of Juvenile Pilocystic Astrocytoma
How do you treat a low grade pediatric tumor?
Resect that shit and radiate/chemo to be sure it is gone.
What are some serum markers for medulloblastoma?
Is it considered to be highly malignant?
TrkC, Erb, C-myc, Neurotrophinin
HIGHLY MALIGNANT primitive tumor
What are the signalling pathway derangements that lead to medulloblastoma?
SHH + Wnt activity (BAD)
SHH active —> inactive PTCH—> ^ Gli2 to nucleus for transc.
Wnt active—> active frizzled—> no degradation of B-catenin
What WHO grade is medulloblastoma?
Describe the molecular determination of prog. based on what pathways are active/inactive.
Grade IV (BAD)
SMO/Wnt active- Good progn.
C-myc- bad prognosis
How does medulloblastoma look on histo?
Blue staining cells in a circle (Homer-Wright Rosettes)
How do we tx medulloblastoma?
surgery + craniospinal radiation
You see a tumor of the brainstem encasing the basilar artery. What tumor is this? How do we tx it?
Diffuse Intrinsic Pontine Glioma
Surgery CONTRINDICATED. Radiotx for amelioration. No cure.
What is the classic triad of Diffuse Intrinsic Pontine Glioma?
CST signs (hemiparesis, weakness), Ataxia, CN 6, 7, 8 signs due to location @ pontomedullary junction
Characteristic histology of ependymomas?
perivascular pseudorosettes, true rosettes
We delay radiation tx until what age, due to the pediatric pt’s developing CNS?
3yo, but ideally 7
