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What are the 4 categories of classification of Brain tumors as per WHO grading?

I. Well circumscribed, slowly progressive can often be cured by resection. "Benign."
II. Infiltrative with low proliferation, higher chances of recurrance.
III. Histologically malignant and require more aggressive adjuvant tx.
IV. Highly malignant and rapidly fatal.


What are the two markers for astrocytoma?

GFAP (Glial Fibrillary Acidic Protein) and Glutamine Synthetase.


What are the 4 WHO types of astrocytomas?

Type I is Juvenile Pilocytic Astrocytoma, II is Fibrillary, III is Anaplastic, and 4 is Glioblastoma multiforme.


Who usually are more prone to astrocytomas?

80% of all adult primary brain tumors are astrocytomas, and they present in the cerebral hemispheres usually from 40-60 yrs of age.


What are some signs and symptoms experienced by patients with astrocytomas?

Seizures, headches, nausea, vomitting, focal neuro headaches.


Describe a diffuse astrocytoma?

Mild/moderate increase in glial cellularity, variable nuclear pleomorphisms, GFAP+ astrocytic processes which makes it look "fibrillary." Transition between normal and neoplasm is indistinct, and it is considered WHO grade II.


Describe an anaplastic astrocytoma?

WHO grade III, more densely cellular, greater nuclear pleomorphism and mitotic activity.


What is "Gemistocytic Astrocytoma?"

The predominant neoplastic astrocyte is brightly eosinophilic with many stout processes.


Given time, what do astrocytomas tend to become?

Tends to become anaplastic or even a type IV if left untreated..


Describe the glioblastoma (previously known as glioblastoma multiforme).

WHO type IV, has the things in type III (pleomorphic cells, increased mitosis, etc), but in addition there is necrosis (very distinct) and vascular/endothelial cell proliferation.


Describe the type of necrosis seen in WHO type IV?

Often serpentine, occurs in areas of hypercellularity, giving the apprearance of "pseudopalisading" of malignant nuclei. (Pseudopalisading necrosis, pseudopalisading meaning cells line up like a picket fence around the necrosis)


What is one proposed factor that leads to vascular proliferation of a glioblastoma?

Malignant astrocytes might secrete VEGF in response to hypoxia (for when tumor grows bigger and requires more oxygen), resulting in vascular proliferation.


What is the difference between primary and secondary glioblastomas? Age and genetic associations?

Primary may arise w/o previous low grade tumor, seen more in older patients. Associated with amplification of the epidermal growth factor receptor gene. Secondary occurs after a previous low grade astrocytoma, which is associated with a mutated p53 gene, and is seen more in younger patients.


Median life expectancy of glioblastoma?

8-10 months regardless of primary or secondary.


What side of the brain does glioblastomas tend to stay at?

They used to be called "butterfly tumors" because they will always cross the midline and thus end up being in both sides of the brain.


In order to be a type IV glioblastoma, what must be present?

Pseudopalisading necrosis + vascular proliferation.


What is the "benign" astrocytoma? What age group is this common?

Grade I, called pilocytic astrocytoma found in children mostly.


What is the classic appearance of this kind of tumor (pilocytic astrocytoma)?

Cystic mass with an enhancing mural nodule.


Where can pilocytic astrocytoma occur? How are they treated?

Frequently seen in the cerebellum but can also be found in the floors and walls of the 3rd ventricle, suprachiasmatic region, optic nerves, hemispheric and spinal. Can be tx-ed surgically if tumor is in an approachable area. Prognosis is good.


What are the classic signs in a histo slide of a pilocytic astrocytoma?

Distinctive bipolar cells with long, thin, hair like GFAP+ processes, and Rosenthal fiber.


Histologically what can be present (although not distinctive) of pliocytic astrocytoma?

Rosenthal fibers.


Buzzwords for Pilocytic astrocytoma?

Children, cerebellum, cystic with a mural nodule, relatively benign. Rosenthal fibers.


Who tends to get oligodendrogliomas?

Older patients in their 40-50's, only ~15% of all gliomas.


What is a common previous complaint of patients with oligodendrogliomas?

Often had seizures for several years and other neurological complaints.


Where do oligodendrogliomas present? How do they look?

Generally in the cerebral hemispheres esp in white matter. They are well circumscribed, gelatenous gray mass, focal hemorrhages and calcification.


How do oligodendrogliomas present microscopically?

Looks like "fried eggs," sheets of regular cells with spherical nuclei w/ finely granular chromatin surrounded by a clear halo of cytoplasm.


How do oligodendrogliomas receive their blood supply, are they calcified, and their WHO classification and mitotic activity?

Delicate network of anastamosing capillaries are their blood supply (chicken wire with the capillary presentation), 90% show calcification, WHO grade II and has very little mitotic activity.


Which are the worse variant of oligodendrogliomas and how do they present?

Anaplastic oligodendrogliomas, these are more rare. Grade III. Increased cell density, nuclear anaplasia, increased mitotic activity and necrosis.


What is the most common genetic change for oligodendrogliomas?

Loss of heterozygosity of chromosomes 1p and 19q.


Which has a better prognosis, oligodendrogliomas or astrocytomas?

Oligodendrogliomas have a 5-10 year survival rate with tx, thus better prognosis.


What are Ependymomas?

Considered glial cell tumor even though it comes from ependymal cells. Appears where ependymal cells are found (in the ventricles, particularly in the 4th ventricle) and most common up to 20 years of age.


If adults have ependymomas, where will it present?

Central canal of the spinal cord, especially in neurofibromatosis, type II. It is the most common spinal cord tumor in adults.


In children how do ependymomas look and why do they have a relatively poor prognosis (4 yr median survival rate)?

They are solid or papillary masses that extends from the floor of the ventricle. It tends to be located near pontine and medullary nucleus so surgical resection is impossible.


How would a child present with ependymoma if it is present in the posterior fossa?

Hydrocephalus due to progressive obstruction of the 4th ventricle and CSF dissemination.


How do Ependymomas present microscopically?

"Perivascular Pseudo-rosettes," tumors form rosettes that look like embryonic ependymal canal with long processes that extend into the lumen (they tend to be perivascular). Regular oval nuclei w/ granular chromatin. Between nuclei however there is dense fibrillary background giving rise to the pseudo-rosettes.


Grade of Ependymomas?

II, anaplastic is III, and despite the relatively good grading the location makes this tumor fatal.


Where does the tumor rise in a child with ependymoma?

4th ventricle or foramen of Lushka/Magendie.


Which type of ependymomas are usually parenchymal? Where do Ependymomas metastisize?

Supratentorial ependymomas. CNS metastasis common.


What are spinal cord ependymomas associated with?

Neurofibromatosis type II, chromosome 22 is involved.


Which kind of ependymoma grows in the filum terminale and how does it look microscopically?

Myxopapillary Ependymoma, shows papillary elements with a myxoid background and ependymoma like cells. Cuboidal cells w/ clear cytoplasm arranged around papillary cores w/ connective tissues and blood vessels.


What are choroid plexus papilloma?

Appears in children in lateral ventricles, 4th ventricle in adults, rare tumor. Looks almost like the choroid plexus structure. Papillary w/ connective tissue stalks with cuboidal and columnar epithelium.


What is the problem with choroid plexus papilloma (minus the fact that it is a tumor).

Can cause hydrocephalus for ventricle obstruction or overproduction of CSF.


What kind of tumor is it if the entirety of the tumor is composed of ganglion type cells?

It's a neuronal tumor, called a "gangliocytoma."


What are gangliomas?

More likely than a gangliocytoma, in this tumor there is ganglion type cells mixed with glial neoplasms.


What previous complain will a patient with a ganglioma complain of?

Previous history of seizures.


Are gliomas rapid or slow?

Most are slow however the glial component can become anaplastic quickly and then progress to rapidly progressing.


How would gangliocytomas present histologically?

Neoplastic ganglion cell clusters present as clumps of cells seperated by more or less acellular stroma.


How would ganglioma's present histologically?

Found mostly in the temporal lobe, might have a cystic component, have neoplastic ganglion cells that are irregularly clustured and have random orientation of neurites. Binucleate forms present.


What are the characteristics of a "poorly differentiated cell" of the CNS? What is the most common type of this called?

Primitive, embryonal, retain cellular features of undifferentiated cells. Express few or no phenotypic markers of mature cells. Medulloblastoma is the most commontype of poorly differentiated CNS tumor.


What is the demographic of Medulloblastoma?

Most common CNS tumor of childhood, peak occurance is about 7 years, 20% of pediatric CNS tumors.


Where do Medulloblastomas arise and how do they look?

Arises in inferior vermis in peds, lateral ventricles. They are small, round blue cells, arising from external granular cell layer of cerebellum.


How do the tumor look macroscopically (tumor being medulloblastoma)? Possible complication and common area of metastasis?

Well circumscribed, gray, friable, extends to surface and might involve the leptomeninges. Can cause hydrocephaly due to CSF block. Metastasis in spinal cord.


Prognosis of medulloblastoma?

Highly malignant but good response to radiation.


How do medulloblastomas present microscopically?

VERY cellular with sheets of small anaplastic cells, little cytoplasm, hyperchromatic nuclei (thus looks very blue) and abundant mitosis, and are undifferentiated. Homer Wright Rosettes (which neuroblastomas also have) can be seen.


Genetic association of Medulloblastoma?

Loss of short arm material of chromosome 17.


What are "Homer Wright Rosettes?"

Tumor cell nuclei arranged in a circular fashioned tangled around cytoplasmic processes. Indicative of differentiation along neuronal lines. No vessels between them.


What is the most common CNS tumor in immunosuppressed patients? What kind of tumor are they?

Primary CNS lymphomas, majority are high grade, large B cell lymphoma.


In the primary CNS lymphoma what kind of genome is found in the transformed B cells?

EBV genome if the patient is immunosuppressed.


Prognosis of CNS lymphomas?

Poor, do not respond well to chemo.


What is seen histologically of CNS tumors and where do they appear?

Multiple foci within the brain and involve deep gray matter, white matter and cortex, particularly the periventricular cortex. Areas of necrosis seen. The malignant cells infiltrate the brain parenchyma and accumulates around blood vessels (Hooping).


What is "hooping" found in CNS lymphomas?

Lymphocytes hoops around in concentric rings around blood vessels.


What are the various types of Germ Cell tumors?

Germimoma, Teratoma, yolk sac tumor, and choriocarcinoma (a seminoma is called a germinoma in the CNS).


What are germ cell tumors basically?

Tumors of the morphologic homologues of the gonads, the presence of non-CNS primary germ cell tumor must be excluded before diagnosing a primary germ cell tumor.


Where are germ cell tumors located?

Almost always midline around the 3rd ventricle, more often in pineal area than suprasellar. However, frequent CNS dissemination.


Who gets germ cell tumors?

Young people 11-20 y/o, however teratomas can appear conginatally. Japanese people tend to get it more and there is a strong male dominance in the pineal region.


How do germ cell tumor present clinically?

Based on where it is impinging, so you can have hydrocephaly, diabetes insipidis, visual problems, pituitary failure or precocious puberty.


Tx of germ cell tumors?

Responds well to radiation but non-germinomatous germ cell tumor less responsive.


What are "Craniopharyngioma?"

Hypothalamic suprasellar tumor and can induce hypo/hyper function of the pituitary.


Where do craniopharyngiomas come from?

Derived from the vestigal remnants of the Rathke pouch.


Who gets craniopharyngioma?

Bimodal, old people or young people (5-15, or 65+).


How do patients present with craniopharyngiomas?

Headaches and visual disturbances, children can have growth retardation and growth hormone deficiency due to pituitary hypofunction. There are also abnormalities within the WNT pathway.


How do craniopharyngiomas look like grossly?

Commonly cystic and multiloculated, might also be solid and encapsulated (rarer). Might impinge the optic chiasm and cranial nerves.


What are the two distinct histological variants of craniopharyngiomas?

2 types: adamantinomatous (most common in children) and papillary (most often in adults but rarer).


Whats special about the adamantinomatous variant of craniopharyngioma in terms of lab tests?

We can see calcifications radiologically.


Prognosis of craniopharyngioma?

If tumor is less than 5 cm then excellent prognosis.


Describe the adamantinomatous craniopharyngiomas histologically.

Nest of cords of stratified sq. epithelium, embedded in spongy epithelium that becomes more prominant in internal layers. Palisading sq epithelium seen in periphery. Compact, lamellar keratin formation (wet keratin) and dystrophic calcification.


What is the diagnostic feature histologically of adamantinomatous craniopharyngiomas?

Compact Lamellar formation and dystrophic calcification. Might also have cyst formation fibrosis and chronic inflamm reactions.


If cysts are present in the adamantinomatous craniopharyngioma, how does it present?

Looks like "motor oil," has a cholesterol rich brown-yellow thick fluid.


How does papillary craniopharyngioma relate to adamantinomatous?

No keratin, no cysts, no calcifications.


Who tends to get meningiomas?

Adults, females more prone than males and may grow during preggo - estrogen receptors.


Where do meningiomas come from? Where are they found?

Arises from meningothelial cells of the arachnoid, usually attached to the dura. Can also be found in the ventricular system where they arise from stromal arachnoid cells of the choroid plexus. Remember Meningiomas arise from Meningiothelial cells of the arachnoid.


Where can meningiomas be found? How do they look?

Dural based tumors, well circumcised and grows from the dura and compresses the brain. Encapsulated within a thin fibrous tissue. Mass can be firm and fibrous to fine and gritty with calcified psamomma bodies.


What is the "en plaque" varient of meningiomas?

Sheet like tumors that spread along the surface of dura, usually associated with hyperostotic changes found in the underlying bone.


What are "psamomma bodies?"

Round concentric calcifications.


What grade and genetic association does meningiomas have?

Grade I, Chromosome 22q.


Which is the most common histological patterns of meningiomas?

Most common is the synctial variant, described as a whirled cluster of cells which sits in group without visible cell membranes.


Which are the most common sites of metastatic cancer coming into the CNS?

Most commonly comes from lung cancer, also breast kidney skin and GI tract cancers.


What is the classic macro presentation of metastatic tumors?

Masses are multiple in the gray-white junction surrounded by zones of edema.


What is the histological presentation of metastatic tumors?

Nodules of tumor with central necrosis and surrounded by reactive gliosis.


What is "meningial carcinomatosis?"

Small tumor cells studding the surface of the brain common in small cell carcinoma, lung adenocarcinoma, and breast carcinoma.


What are Schwannomas? Are they malignant?

May be associated with neurofibromatosis type II, arise from neural crest cell derived schwann cells. They are benign, symptoms are associated with the nerves they impinge.


What genes are involved in the sparodic form of Schwannomas?

NF2 gene in chromosome 22.


How do schwannomas look? Neurilemomma is aka as Schwannoma.

Well circumscribed encapsulated mass attached to the nerve but can be seperated from it. Firm, gray, can have cystic or xanthomatous (yellow and fatty)changes.


What are the two distinct microscopic patterns of schwannomas?

Antoni A and Antoni B areas. Antoni A will basically present as a lot of cells with little stroma in the periphery and have a center area with very little nuclei, which is called a "Verocay body." Antoni B is less dense, has meshwork of microcysts and mixoid changes.


What happens if the schwannoma grows in the cerebellopontine area of cranium?

It becomes an "Acoustic Neuroma" because CN8 is nearby, tinnitus and hearing loss is associated.