6/15- Neuro-oncology II Flashcards
What is the most common primitive neuroectodermal tumor of the brain?
Medulloblastoma
What are the major gliomas?
- Astrocytomas
- Oligodendroglioma
- Ependymoma
What is the importance of the 1p/19q co-deletion?
Prognostic indicator in oligodendrogliomas
Breakdown of different types of neural tumors (flowchart)
What tumors are grade IV?
- PNET: medulloblastoma
- Glioblsatoma multiforme
What is the grade I tumor primarily focused on in this lecture?
- Juvenile pilocytic astrocytomas
What demographic is most commonly afflicted with medulloblastomas?
2nd most common?
- Common childhood brain tumor
- Second peak in young adults
What is this? Symptoms?
Medulloblastoma
- Tends to arise in posterior fossa
- In scan, can see midline hyperdensity
- In gross specimen, can see tumor draping over pons arising mostly from the ventricles
- Would initially see midline (vermal) ataxia, followed by limbs
The word “anaplastic” identifies the tumor as what?
Grade III
Which of the “big 4” tumors commonly arise in the ventricles?
- Ependymoma
- Medulloblastoma
What is this? Features?
“Small blue cell tumor” (Medulloblastoma)
- Hypercellularity (too many cells)
- Little/no cytoplasm
- Very irregular nuclei (in size and shape); “nuclear pleomorphism” or “nuclear atypia”
- Tumors can start to show some features indicating that they’re trying to differentiate
(Homer-Wright rosette- central space within circle-forming cell indicating early differentiation of this primitive neuroectodermal tissue. Indicates that this is a medulloblastoma; bottom-left picture)
What is this?
Tumor cells that have broken loose and gotten into CSF, “drop metastases”
- Medulloblastoma in CSF (CSF cytology)
- Can see that they’re even trying to forma Homer-Wright rosette here (upper)
What is this?
Glioblastoma multiforme crossing the midline via the corpus callosum
- No distinct borders; terribly infiltrative
- Fast-growing
- These tumors love to cross at the corpus callosum
- Pattern of growth known as “butterfly glioma”
What is this?
Glioblastoma multiforme
- Terribly fast growing!
- Additional tumor, edema
- Dark areas are probably necrosis within tumor (growing so fast that they outstrip blood supply)
What is this? Symptoms?
Diffuse intrinsic glioma of the brainstem (one of the big 4 childhood tumors)
- Maybe some cerebellar ataxia
- Probably will spread to pick off cranial nerves
What is one of the most common gliomas in adulthood?
Glioblastoma multiforme
T/F: Glioblastomas can occur in the posterior fossa
True; see past picture of DIG in the brainstem
What is this?
Glioblastoma multiforme histopathology
- Hypercellularity
2 key histological features to diagnose glioma as glioblastoma (grade IV):
- Vascular proliferation- subset of tumor cells have mutated, allowing them to stimulate new vessel growth; very unregulated, no tight junctions (will leak contrast) (top L darker circles and top R)
- Necrosis- outstripping blood supply (bottom L, bottom R); cells lining up at area of necrosis
What is this?
Glioblastoma multiforme
- Can’t really tell what these are other than just big, bad tumor cells (“monster cells”)
- Cell on the left is multinucleate
- To prove it’s a glioma, need to stain with GFAP
What is this?
(“Monstrocellular”) Glioblastoma multiforme
- GFAP imunopositive
What is this?
Glioblastoma multiforme with extreme cellular pleomorphism
- High potential for mutation (radiation/chemo resistance)
What is this? Expected symptoms?
Anaplastic astrocytoma (found on histology)
- Squished ventricle
- Abnormality down in temporal lobe
- No distinct border; infiltrative
- Like glioblastoma, but no vascularization and no necrosis
Symptoms:
- Loss of hearing
- Memory disturbances
- Partial complex seizure (often associated with olfactory aura; clouding of consciousness)
What is this?
Anaplastic astrocytoma
- Hypercellularity (normal in top left)
What is this?
Anaplastic astrocytoma
- Hypercellular
- Can see 5 mitoses (mitotically active)
- No vascularity (see normal BV in bottom right), or necrosis
- May progress to glioblastoma (since mutationally active)
Common treatment for glioblastoma (and anaplastic astrocytoma)?
- Debulk via surgery
- Radiation therapy
- Tenozolidimide
What is this?
Anaplastic astrocytoma
What is this?
Low grade astrocytoma (normal top left)
- Slight hypercellularity
- Variation and nuclear morphology (subtly nuclear atypy)
- If you start to see mitotic activity, then it moves up to anaplasty
- Low grade astroyctoma may progress into anaplastic and then possibly GBM (glioblastoma multiforme)
- May have partial complex seizures
Survival times (with treatment) for glioblastoma multiforme vs. anaplastic astrocytoma?
Glioblastoma multiforme: 12 mo survival on treatment
Anaplastic astrocytoma: 24-36 mo on treatment
Treatment for low grade astrocytoma?
We don’t really know; don’t want to treat with low therapy with high chance for resistance development
What is this?
Optic nerve glioma (pilocytic astorcytomas (grade I))
- Can see faint line of dura
- Tumor has spread into subarachnoid space
What is this?
Bilateral optic nerve glioma
- Pilocytic astroytomas (grade I)
- Will take vision but typically not kill you (unless in hypothalamus)
What is this?
Pilocytic astrocytoma
- Hypercelluarity
- Thick process (pear-like) -> “pylocytic”
- Reddish, amorphous, cork-screw like collections (Rosenthal fiber)
Characteristics of pilocytic astrocytoma?
- Well circumscribed
- Rarely infiltrative
What is this?
Infiltrating glioma
- Intraparenchymal (intra-axial) contrast enhancing mass without distinct borders
- Astrocytoma is likely (must differentiate from oligodendroglioma) ?
What is this?
Oligodendrolgioma, grade II (analogous to astrocytomas grade II)
- “Fried egg” cells
What is seen in the molecular biology of oligodendroglioma?
Features tied in with outcome?
Loss of heterozygosity 19q and 1p
- Recent studies indicate that a clinically significant subset of oligodendroglial tumors show co-deletion on chromsomes 1p and 19q
- Response to therapy is much better in pts with co-deletion 1p/19q
What is the difference is seen in the mean survival of pts with different 1p/19q characteristics?
- Not co-deleted: 12 mo (1 yr)
- Co-deleted: 124 mo (10 yrs)
Treatment for oligodendroglioma?
Combination chemo-therapy with regimens such as PCF or single drug temozolamide with/without radiation (XRT)
(PCV: procarbazine; CCNU and vincristine)
What is this?
Ependymom
- Intraventricular or in association with central canal of SC
- 4th ventricular tumor on L picture (obstructive symptoms)
What is a key difference in medulloblastomas and epndymomas that both can arise in 4th ventricles?
- Medulloblastoma is way faster-growing
- Ependymoma tumors will try to create little ventricles
Which tumors are typically more easily removed (surgically resectable)?
- Pilocytic astrocytoma
- Ependymoma
What is this?
Ependymoma in 4th ventricle
What is a risk of both medulloblastomas and ependymomas?
Dissemination through CSF (since in contact); more commonly happens with medulloblastomas
What is this?
Epnedymoma disseminated through ventricular system
What is this?
Ventricular tubule with a lumen (tiny ventricle)
- Ependymoma (?)
What is this?
Perivascular paucinuclear zone with surrounding cells
- Very commonly seen in ependymomas
What is seen ultrastructurally in ependymomas?
- Tight junctions
- Cilia
What is this?
Grade?
Origin?
Symptoms?
Colloid cyst of the 3rd ventricle (grape-like structure)
- Grade I
- Arises from ependyma (modified- ependyma)
- Positional hydrocephalus may result in sudden death (but typically, doesn’t cause too much trouble)
What is this?
Colloid cyst of the 3rd ventricle
What is this?
Central neurocytoma
- Intraventricular mature neuronal tumor
- (“cytoma” typically means more mature)
What is this?
Central neurocytoma
- Clear halo cells-oligo-like
- Neuronal features by EM and immunohistochemistry
4 main childhood tumors?
- Medulloblastoma
- ?
- Ependymoma
- Pontine glioma (diffuse intrinsic glioma of pons)
