CNS Tumors Flashcards
In adults, are most primary brain tumors infratentorial or supratentorial?
supratentorial
opposite from kids, where most are infratentorial
What is the most common symptoms of a brain tumor?
headache
seizure
altered mental status
What chromosome is neurofibromatosis 1 on? What tumors do you get in NFT1?
17
gliomas of the optic nerve and ependymoma
What chromosome is neurofibromatosis 2 on? What tumors do you get in NFT2?
22q12
meningioma and glioma
What chromosome is von Hippel-Lindau on? What tumor go you get with VHL?
3p25
hemangioblastoma
What chromosome is the Li-Fraumeni cancer family syndrome on? What brain tumors do you get?
17p13.1 (an inherited p53 mutation)
glioma and medulloblastoma
What are the two most important prognostic factors for brain tumors?
histologic type and patient age
What are the two most common primary brain tumor types?
gliomas and meningiomas
Glioma is a generic histologic term used for what four different CNS tumors?
astrocytoma
oligodendroglioma
ependmoma
choroid plexus papilloma
(it’s basically just a tumor of the glial cells)
What cell type does glioblastoma multiforme arise from?
astrocytoma (it’s just a grade IV astrocytoma)
What is the peak age of onset for GBM?
40-60 yo
Describe the pathology of GBM.
highly malignant tumor with anaplsia, high cellularity, round and pleomorphic cells, nuclear atypia, vascular proliferation, and necrosis
(the necrosis and neovascular proliferation are what differentiate a GBM from a grade III astrocytoma)
Where in the brain are GBMs typically located?
deep white matter, basal ganglia, or thalamus (rarely infratentorial)
What will a GBM look like on CT or MRI?
usually a solitary mass with contrast enhancement and surrounding edema
often infiltrating the corpus callosum producing the typical “butterfly” pattern
What is the typical treatment for a GBM?
- maximal safe surgical resection
- radiation with concurrent temozolomide
- adjuvant temozolomide for 6 months
in addition: nitrosoureas are considered for combo therapy and bevacizumab can be used for local recurrences
What is the life expectancy in GBM?
not good. less than 3-5 yr survival
What will a low-grade astrocytoma look like on MRI with contrast?
bright on T2 and FLAIR, usually without enhancement (unlike the GBM which usually enhances)
What is the treatment for grade 1 and 2 astrocytomas?
close observation with serial imaging may be the first approach depending on prognostic factors because these can be very slow growing
surgical removal can be curative for grade I astrocytomas and can be considered for grade II if the gross total resection is possible (but is often not curative)
What is the median survival for low grade astrocytoma?
around 7 years
What is the “genetic signature” of oligodendrogliomas?
codeletion of chromosomal arms 1p and 19q
and people with this codeletion tend to respond better to therapy
Where is the most common location for an oligodendroglioma?
frontal lobe most common
but also basal ganglia and thalamus
Describe the pathology of an oligodendroglioma.
most distinctive microscopic feature is the “fried egg” appearance with perinuclear halos with swollen cytoplasm
calcifications are common
What will an oligodendroglioma look like on MRI? CT?
MRI with low intensity on T1, high intensity on T2, vasogenic edema is NOT common. If it enhances, that’s a bad prognostic factor
CT scan is better to see the calcifications
What is the treatment for an oligodendroglioma?
total resection if possible, local radiation and PCV (procarbazine, lomustine and vincristine) chemotherapy
Temozolomide is used increasingly
What is the prognosis for oligodendroglioma?
better survival with surgery plus radiation; can be decades
however, it tends to recur locally and progress into a malignant form
What cells do meningiomas originate from?
the meningothelial cells of the dura mater
Meningiomas rarely occur intracranially, but when they do, where are they?
cerebral convexities, falx cerebri, and the sphenoid wing
What genetic condition is associated with a higher risk for meningiomas?
NF-2
Describe the pathology of a meningioma.
sheets of plump, uniform meningothelial cellswith the tendency to form whorlds
What receptors are found frequently in meningiomas?
progesterone (probably why they’re more common in women)
What will a meningioma look like on MRI?
a rounded extra-axial mass adjacent to the dura
isointense on T1 and T2 with intense contrast enhancement
What will a meningioma look like on CT?
calcifications seen on CT
angiography can show rich vascularization
can also see hyperostosis, which is an osteoblastic reaction that occurs if the tumor is invading the skull
What is the treatment for meningiomas?
surgical removal, often preceded by endovascular embolization of the feeding vessels
stereotactic radiosurgery is an option when resection is difficult or dangerous
What is the prognosis for meningiomas?
5-yr survival rate at 70-95%
malignant transformation is rare
What is the origin of medulloblastoma?
primarily at the medullary velum of the 4th ventricle
it’s one of the primitive neuroectodermal tumors
Medulloblastoma makes up what percentage of pediatric primary brain tumors?
30%
Describe the pathology of medulloblastoma.
small round cells with a high mitotic index
What is the typical presentation of a medulloblastoma?
It’s rapidly growing and infiltrates surrounding tissue and the 4th ventricle, so you get a hydrocephalus with morning headaches, unsteadiness, nausea and vomiting
What will a medulloblastoma look like on MRI?
a heterogeneous contrast enhancing midline tumor compressing the 4th ventricle
Why do you also do an MRI of the c-spine after a diagnosis of medulloblastoma?
it can metastasize to the subarachnoid along the spinal cord
What is the treatment for medulloblastoma?
surgery plus radiation and chemo
corticosteroids for vasogenic edema
What is the prognosis of medulloblastoma
20-30% will relapse after initial treatment
poor prognosis with metastatic disease or subtotal resection ( no duh)
good prognosis with radical resection and radiation dose above 50 Gy to the entire neuroaxis, in which case recurrence-free survival at 5 years is over 50%
Where is the most common location for a schwannoma?
cranial nerve VIII - an acoustic neuroma occupying the cerebellopontine angle
Bilateral schwannomas is associated with what disorder?
NF-2
Describe the pathology of a schwannoma.
sheets of uniform spindle cells forming palisades called “Verocay bodies”
Where do hemangiomas occur in the brain?
cerebellum - it’s a cystic lesion
Primary CNS lymphoma is rare, but has a higher incidence in what patients?
AIDS patients, particularly men
WHat is the treatment of choice for CNS lymphoma?
high-dose systemic methotrexate-based chemo +/- radiation
What is the prognosis for CNS lymphoma?
poor
1.5 months if untreated, 10-18 months after radiation and 44 months after chemo plus radiation
What is a common complication in patients who survive over 18 months with CNS lymphoma after radiation?
dementia (so shitty)
Primary CNS lymphoma can have a dramatic response to what class of medication? (although it invariably recurs within months).
steroids
What is the size difference between a microadenoma and macroadenoma of the pituitary?
1 mm
Surgical removal of the pituitary is via what approach?
transsphenoidal
What tumor affecting the pituitary comprises 50% of suprasellar tumors in children?
craniopharyngioma
What is the radiologic hallmark of a craniopharyngioma?
suprasellar calcified cyst
What are the most common tumors that cause metastases to the brain?
lung skin (melanoma) renal cell carcinoma breast colon
What are the two routes malignant cells will take to seed the CNS?
via the bloodstream crossing the BBB
through Batson’s plexus (pelvic and GI tumors)
In general, where in the brain are mets located?
at the junction of the white-gray matter
