CNS Tumors: Bemis Flashcards
Describe primary CNS tumors.
Poorly circumscribed, usually single, location varies by type.
Describe metastatic tumors to the CNS.
Well circumscribed, multiple, junction between gray and white matter, often pleomorphic (variable shaped nuclei), infiltrate via pathways of least resistance.
What does the WHO Grading intended to do?
Predict the biological behavior of a tumor and to influence your choice of therapy
What is adjuvant treatment?
Follows primary treatment. The goal is to remove any residual cancer cells.
Where are 70 % of tumors in children?
Posterior Fossa
Where are 70 % of tumors in adults?
Supratentorial
What is a WHO Grade 1 tumor like?
Low proliferative potential, possible to cure following resection alone!
What is a WHO Grade 2 tumor like?
Infiltrative but low proliferative activity, if removed will often recur (>5 year survival)
What is a WHO Grade 3 tumor like?
Histological evidence of malignancy: nuclear atypic and much mitotic activity (2-3 year survival).
What is a WHO Grade 4 tumor like?
Cytologically malignant, mitotically active, necrosis prone, usually fatal.
How does radiation work?
Breaks DNA to induce death.
What type of cells are often resistant to radiation?
Brain tumor stem cells.
What types of cells to Gliomas (Astrocytomas) usually arise from?
Astrocytes, Oligodendrocytes, Ependymal cells
What often prevents complete excision of Gliomas?
Infiltrative borders
What is the highest grade, most malignant Astrocytoma?
Glioblastoma
Describe the Astrocytoma grading scale.
I. Pilocytic Astrocytoma (benign: low proliferative potential)
II. Diffuse Astrocytoma (Low proliferative potential but infiltrative)
III. Anaplastic Astrocytoma (shows more cellular regions, more pleomorphism, more mitosis)
IV. Glioblastoma (necrosis, microvascular proliferation)
Describe Pilocytic Astrocytomas. Who usually gets them?
Often cystic, bipolar cells with long hair-like processes. Contain Rosenthal Fibers (Corkscrew morphology, very pink, composed of GFAP (Glial Fibrillary Acidic Protein)), Biphasic (lose and dense areas).
Children
Excellent prognosis
If you have a mutated BRAF (detected using FISH), the outcome is generally worse.
Describe Diffuse Astrocytomas. Who usually gets them?
Slowly progress into Anaplastic Astrocytomas. Surgical removal then radiation.
Histology: Gemistocytic astrocytoma
The presence of fibrils is not good.
Genetics: Oligodendrocytomas do better.
Age: 20’s-40’s
Why isn’t chemo good for a diffuse astrocytoma?
Because the cells are growing slowly.
Describe Anaplastic Astrocytoma.
GFAP positive. Mitotic figures.
Why do we see GFAP?
It is a principle intermediate filament in mature astrocytes. It modulates astrocyte motility and shape. Following an injury, astrocytes are activated –> Astrogliosis –> Rapid synthesis of GFAP.
Describe a Glioblastoma.
MOST COMMON PRIMARY BRAIN TUMOR IN ADULTS AGE 45-75. Mean survival: 10 months.
Pseudopalisading necrosis.
Butterfly glioma: crosses midline via corpus callosum.
Sx: progressive motor weakness, headaches, Increased ICP, Seizures.
Why do we need to know if we are working with a primary or secondary Glioblastoma?
For treatment purposes.
Primary are a Glioblastoma from the first symptom (EGFR, p53 mutations).
Secondary are formed from a common precursor mutation in IDH 1/2 (Can differentiate into Diffuse astrocytoma or Oligodendroglioma which can both become secondary Glioblastomas).
Describe an oligodendroglioma.
Less common (10 % of gliomas in adults).
Sx. Seizures.
Mean survival: 10 years.
Deletion of 1p and 19q improves survival.
Morphology: sharply circumscribed round nuclei with cytoplasmic halos. Most are calcified. Delicate capillary network.
Describe an ependymoma.
Usually in kids, near the 4th ventricle.
Slow growing but have a 4 year prognosis.
Morphology: Rosettes and pseudorosettes.
What is the adult version of a ependymoma called and where is it located?
Myxopapillary variant. It is in the spinal cord.
Describe a medulloblastoma.
WHO Grade IV. Children. Very radiosensitive Cerebellum. Males>females
i(17q) = poor prognosis (it is an isochrome: puts p and p or q and q of chromosome arms together).
Histology: Homer-Wright Rosettes (proteins in the center).
Describe a meningioma.
2nd most common primary brain tumor. Benign. Tumor of arachnoid cells. Slow growing. Attached to dura and compresses brain.
Histology: Synctial (swirling pattern)
Psammoma bodies (calcium deposits).
Describe a schwannoma.
3rd most common brain tumor.
Commonly located at CN VII at the cerebellopontine angle.
Hearing loss, tinnitus.
Good prognosis after surgery.
