CNS Tumors - Cochran Flashcards
Distinguish between the frequency and presentation of CNS tumors in adults and children.
Are metastases or primary tumors more common?
Adult tumors are generally supratentorial. Pediatric brain tumors are infratentorial and more common.
According to lecture, metastases are more common. According to Pathoma, they are equal.
Why are even low-grade CNS tumors very dangerous?
How apt are the high-grade to spread to other sites?
The brain is enclosed, meaning any mass expansion could be catastrophic. Focal involvement can be serious and resection difficult.
Not very apt (Medulloblastoma is a key exception to this)
What is the most common glioma?
What form is most common in adults?
In children?
Astrocytoma.
Glioblastoma multiforme
Pilocytic astrocytoma
Pilocytic Astrocytoma
Who does it affect? Where does it manifest?
How does it appear on histology?
Prognosis?
Pilocytic Astrocytoma
Mostly children; hence it is found in the cerebellum (infratentorial!)
Biphasic pattern of fibrillary and microcystic areas. Generally loose and low-grade, with Rosenthal fibers (eosinophilic, astrocytic)
Good! Well-demarcated with slow growth. Pilocytic astrocytoma does not progress to grades II/III/IV astrocytoma.
Contrast grade II astrocytoma with grade III.
In grade II astrocytoma, cellularity is moderate and nuclear atypia is only occasional.
In grade III astrocytoma, both features are worse, and mitoses can be found.
What is grade 4 astrocytoma also known as?
How does it appear grossly?
On histology?
Glioblastoma multiforme.
Apt to cross the corpus callosum and cause subfalcine herniation. May seed the ventricles.
Pleomorphic with rich mitotic activity. Necrosis with pseudopalisading, and endothelial proliferation (“glomeruloid”).
Oligodendroglioma
Adults or children?
Grades?
Prognosis?
Oligodendroglioma
Adults.
Unlike astrocytoma, only presents as grade II and III (anaplastic).
Better than astrocytomas.
What genetic trait should be determined in an oligodendroglioma to direct treatment?
How does it appear on histology?
On radiology?
Loss of chromosomes 1p and 19q.
Sheets of cells with round nuclei (“Fried egg” appearance)
Well-defined lesion, maybe with calcification.
Ependymoma
Adults or children?
Grades?
Where is it usually found, and what are the consequences of this?
Ependymoma
Children mostly, but also young adults.
Unlike astrocytoma (but like oligodendroglioma), only grades II and III (anaplastic).
Around the ventricles, may cause hydrocephalus.
Ependymoma
How does it appear grossly?
On histology?
What factor do these stain positive for?
Ependymoma
Can be solid or cystic, prodrudes from ventricular lining.
Rosettes of columnar cells (sometimes perivascularly; “pseudorosettes”).
GFAP (recall that ependymal cells, like astrocytes, express this)
Most gliomas are sporadic. Some can result from genetic mutations or environmental factors. Try to name 3-4 of these risk factors (for familial causes, give the syndrome name and associated tumors).
p53 mutation (Li-Fraumeni); Astrocytomas
DNA mismatch repair mutations (Turcot); Glioblastoma & Medulloblastoma
PTEN mutation (Cowden); Gangliocytoma
(NF1, NF2, Tuberous sclerosis, VHL)
Therapeutic radiation (such as for treating childhood ALL)
Choroid plexus papillomas are not the same thing as ependymomas! Still, name their complications.
Are they benign or malignant?
Hydrocephalus again (obstruct outflow or overproduce)
Can be either; benign has good prognosis, while malignant has dismal (occurs in young children)
Where can colloid cysts be found?
What condition will the patient complain of?
How do they appear on microscopy?
Usually at the roof of the 3rd ventricle, near the foramen of Monro.
Positional headache due to obstruction of the foramen.
A thin-walled cyst with cuboidal/columnar lining.
Where can gangliogliomas be found?
What condition will the patient exhibit?
What is distinctive about the treatment of ganglioglioma?
Usually in the temporal lobe (note: CNS only!)
Seizures, usually.
Surgery alone is usually curative!
Gangliogliomas are (well-circumscribed/poorly-differentiated).
On histology both neuronal and glial components will be found. Which is actually neoplastic?
Well-circumscribed.
The glial component (this should be intuitive; neurons have little proliferative potential)
Medulloblastoma is a (neuronal/glial) tumor of (adults/children). It is generally found in ______, causing the symptoms of ______. It has a (favorable/dismal) prognosis.
Neuronal (actually neuroectodermal), in children. Posterior fossa, look for cerebellar defects (ataxia). Dismal prognosis.
Describe the treatment for medulloblastoma.
Why might an adjuvant treatment be needed?
Surgical resection followed by craniospinal radiation.
The radiation is for treatment of “drop metastases” in the lower spine.
Does medulloblastoma appear highly irregular or typical on histology?
What factor, stainable in IHC, affirms medulloblastoma’s neuroectodermal origin?
What eponymous finding is seen on histology?
Highly irregular! Recall that most medulloblastoma is grade IV.
Synaptophysin.
Homer-Wright rosettes.
What is the classic etiology of a primary CNS lymphoma?
What is it’s outlook?
Histology?
EBV-associated, seen often in immunocompromised hosts (some immunocompetent as well)
Dismal, most die within 1 year.
Periventricular and perivascular expansions.
Who is the classic meningioma patient?
What are some classic sites?
What is its etiology & known associations?
An older woman.
Parafalcine, orbitofrontal, on the sphenoid ridge, etc. Anywhere there’s dura, really…
Unknown, though these are generally ER/PR+. Associated with radiotherapy and NF2 gene mutation.
What histologic findings are seen in low-grade meningioma?
On high-grade?
Which is more common?
Whorls of cells, psammoma bodies.
As above, plus the usual bad signs (necrosis, mitoses)
Low-grade (90% are Grade I).
Name five sources of metastases to the CNS.
How do they appear on imaging?
Histology?
Lung & Breast >> Kidney, Skin, and GI tract.
Multiple & well-demarcated.
Resembles the tissue of origin.
Some tumors have a particular predilection for CNS metastasis.
What metastases can spread through/along the meninges?
What metastases target the lumbar spine, potentially causing cord compression?
Breast cancer is prone to this (Meningeal carcinomatosis)
Prostatic adenocarcinoma spreads to lower spine (remember? Batson venous plexus?)
Are schwannomas benign or malignant? In adults or children?
What is the most classic site of appearance?
Any genetic associations?
Benign, more commonly in adults.
The cerebellopontine angle, where CN VIII emerges (note deafness/tinnitis, facial numbness)
Neurofibromatosis type 2.
