What are the processes of life/death in balance physiologically?
Brain tumors are 2nd only to ____ in malignancies of childhood?
Brain tumors are 2nd only to leukemia in malignancies of childhood?
At the most fundamental level, cancer is a set of disorders characterized by _________?
At the most fundamental level, cancer is a set of disorders characterized by mutations of genes regulating cell growth, differentiation, and death
(as cell proliferation, differentiation, and programmed cell death are under genetic control)
Tumor progression results from __________?
Tumor progression results from the sequential acquisition of new mutations which confer selective advantage
How are nervous system tumors named?
(Like other tumors)
According to the similarity of the tumor cells to architecture of normal tissues during development
CNS tumors are ____ (graded/staged) but not ____ (graded/staged). Definitions?
CNS tumors are graded but not staged
Staging = gross size and spread of tumor (local, nodal, systemic...)
Grading = only and ever histological (although may be used to estimate/predict tumor behavior; grades 3/4 are more likely infiltrative, but neuro-tumors are not officially staged)
Cellular constituents of the nervous system (3 broad categories)?
- Neuroectodermal elements
- Mesenchymal elements
- Neural crest
Cellular constituents of the nervous system (details)?
- Microglia and lymphocytes
- Blood vessels
- Schwann cells
T/F: These are normal neurons?
What immunomarkers can be used for neurons?
- Synaptophysin (reddish)- stains synapses
- Neu-N (dark, more well-defined)
What is this?
Neu-N (immunomarker for neurons)
What is this?
Synaptophysin (immunomarker for neurons)
What is this?
Glia in the neuropil
- Oligodendrocyte has smaller, denser nucleus (maker of myelin in the CNS) than astrocyte
Whit is this?
Reactive astrocytes (marks process of gliosis)
- Increased protein synthesis
- Prepares to form scar-like tissue
- Eosinophilic cytoplasm in astrocyte may be reactive or neoplsatic
What immunomarker can be used for glia?
Glial Fibrillary Acidic Protein (GFAP)
- Center of the picture is astrocyte highlighted by GFAP (star-shaped with many processes branching out to touch synapses, forming tight junctions around endothelial cells of BVs..)
- GFAP is stronger in astrocytes than ependymal cells and oligodendrocytes
What immunomarker can be used for oligodendrocytes?
No good immunomarkers (have tried myelin-based proteins, but hasn't worked yet)
- On pic, can see them lining up to support neurons
- Make myelin (CNS)
What is shown on the left? right?
Left: normal oligodendroyctes
Key difference is that there are more cells on the right (hypercellular); this would be a well-behaved (low-grade) tumor
When cut this way, look like "fried-egg" cells (characteristic of oligodendrocytes); have that halo around them
What is this?
- Line the ventricles and central canal of SC
What is a good immunomarker for ependyma?
No good immuno; however, EM shows microvilli and cilia (more epithelial characteristics than other cells)
What can be used to mark meningothelial cells?
EMA: epithelial membrane antigen
(have desmosomes- dura is very tough)
How do nervous system tumors produce symptoms?
What are these symptoms?
Compressing or invading adjacent neural tissue
- Therefore, focal signs and symptoms are common in pts with these tumors
- May result in seizures (especially in cortex) or other deficits
- In addition to focal effects, CNS tumors produce increased ICP, with its attendant signs and symptoms
In addiction to classification along histological lines, tumors should be organized by _________?
In addiction to classification along histological lines, tumors should be organized by gross localization:
- Dura, subarachnoid, intraparenchymal (also "intra-axial") or intraventricular
What is Nissl substance?
Found in Rough ER; marker for neurons (?)
In children, brain tumors tend to occur where? Examples?
In the posterior fossa:
- Medulloblastoma (primitve neuroectodermal tissue; small blue cells that may look relatively normal)
- Diffuse intrinsic glioma of the pons, DIG (pontine glioma)- will take out ipsilateral CNs and long tracts (contralateral Sx)
- Pilocytic astrocytoma
____ (low/high) grade tumors are more serious?
High grade tumors are more serious?