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