CNS Tumors Flashcards
Tumors of Astrocytes:
- Circumscribed - Minimal brain ____
Can be completely resected or cured.
MC in ___!
Circumscribed Pilocytic Astrocytoma (MC, primary, benign)
Incidence: Most common primary brain tumor in children (____% of pediatric CNS tumors)
Onset: Usually present by age 20 years, but can manifest in adulthood
Gender: No gender predilection
Location: May arise anywhere in the ___. Most common site is the ____ (infratentorial)
Classic appearance of a pilocytic astrocytoma: ___ with a contrastenhancing mural nodule, located in the __.
Cytologic preparation of a pilocytic astrocytoma. Notice the fine __-___ processes and ropey, red structures (red arrows) called ___ fibers.
Genetics: ___-___ fusion is found in around ___% of pilocytic astrocytomas. Approximately ___% of pilocytic astrocytomas have an activating point mutation in the __ gene (___E mutation).
2. Diffuse
- Highly ___
Cannot be completely resected or cured
- MC in ___.
- Supratentorial Diffuse
- Most ____ category of astrocytoma in adults
Age and gender: ___ > ___
__ = __
Location = ____ (most common)
Grading__ to ___
Low grade –> ____
High grade –> ____
___: Non-enhancing
___: Patchy enhancement
___: Ring enhancement
Secondary Glioblastoma: GB developed from a lower grade astrocytoma. __ and ___ mutation (MC mutation early on).
__ mutations have a BETTER prognosis than __.
Primary Glioblastoma - developed without a __ of a lower grade astrocytoma. Tend to have ___ mutations and__ overexpression. Isocitrate dehydrogenase (IDH) and TP53 gene mutations are early events in the formation of diffuse astrocytomas. They are found in 60-70% of cases. IDH mutations are associated with a better prognosis.
Tumors of Astrocytes:
- Circumscribed - Minimal brain infiltration.
Can be completely resected.
MC in children!
Circumscribed Pilocytic Astrocytoma (MC, primary, benign)
Incidence: Most common primary brain tumor in children (35% of pediatric CNS tumors)
Onset: Usually present by age 20 years, but can manifest in adulthood
Gender: No gender predilection
Location: May arise anywhere in the CNS. Most common site is the cerebellum (infratentorial)
Classic appearance of a pilocytic astrocytoma: cyst with a contrastenhancing mural nodule, located in the cerebellum.
Cytologic preparation of a pilocytic astrocytoma. Notice the fine hair-like processes and ropey, red structures (red arrows) called rosenthal fibers.
Genetics: KIAA-BRAF fusion is found in around 70% of pilocytic astrocytomas. Approximately 10% of pilocytic astrocytomas have an activating point mutation in the gene (V600E mutation).
2. Diffuse
- Highly infiltrative
Cannot be completely resected or cured
- MC in adults.
- Supratentorial Diffuse
- Most common category of astrocytoma in adults
Age and gender: adults > children
male = female
Location = cerebrum (most common)
Grading II to IV
Low grade –> non-enhancing
High grade –> enhacing
grade II: Non-enhancing
grade III: Patchy enhancement
grade IV: Ring enhancement
Secondary Glioblastoma: GB developed from a lower grade astrocytoma. IDH and TP53 mutation (MC mutation early on).
IDH mutations have a BETTER prognosis than TP53.
Primary Glioblastoma - developed without a history of a lower grade astrocytoma. Tend to have PNET mutations and EGFR overexpression. Isocitrate dehydrogenase (IDH) and TP53 gene mutations are early events in the formation of diffuse astrocytomas. They are found in 60-70% of cases. IDH mutations are associated with a better prognosis.
Oligodendrocytes –> Oligodendroglioma (___% of all primary brain tumors)
Incidence: Less common than ___
Age and gender: Affects mostly __
Gender: Male ___ female
Location: ______ is the most common location -
___ tumors - No ___ forms
Grading ___ (__) to ___ (__)
Low grade tumors may “___” to high grade tumors Oligodendroglioma, WHO Grade III is referred to clinically as “___ oligodendroglioma”
___ of chromosomal arms__ and ___ are found in __-___% of oligodendrogliomas. ____/____ deletions are associated with a better prognosis, even with high-grade tumors
Classic appearance of an oligodendroglioma: ___nuclei, ____ clearing (halos), and a delicate network of capillaries.
Tumor cells in oligodendroglioma are said to look like ___s. These have rounded nuclei and clearing around nucleus.
Grade III Oligodendroglioma, WHO grade III, has necrosis and hemorrhage; notice that it crosses into the _ __.
Oligodendroglioma, WHO grade III exhibits ___ endothelial proliferation. This correlates to the ___ we see radiologically
Oligodendrocytes –> Oligodendroglioma (2.5% of all primary brain tumors) Incidence:
Less common than astrocytomas
Age: Affects mostly adults
Gender: Males = Females
Location: Frontal lobe is the most common location
Infiltrating tumors - No circumscribed forms
Grading II (low) to III (high)
Low grade tumors may “progress” to high grade tumors Oligodendroglioma, WHO Grade III is referred to clinically as “anaplastic oligodendroglioma”
Deletions of chromosomal arms 1p and 19q are found in 60-80% of oligodendrogliomas. 1p/19q deletions are associated with a better prognosis, even with high-grade tumors.
Classic appearance of an oligodendroglioma: round nuclei, perinuclear clearing (halos), and a delicate network of capillaries.
Tumor cells in oligodendroglioma are said to look like eggs. These have rounded nuclei and clearing around nucleus. Grade III Oligodendroglioma, WHO grade III, with necrosis and hemorrhage; notice that it crosses into the corpus callosum
Oligodendroglioma, WHO grade III exhibits vascular endothelial proliferation. This correlates to the enhancing we see radiologically.
Ependymoma:
Incidence: account for %___ of ____ brain tumors.
Age/gender: ___. Male __ female
Location: __ __ (__ ventricle / cerebellum)
Grading: __ to ___. Most are __
The tumors are centered in the region of the __ __ and has a ___, and ___ pattern. Because they grow within the ___system, they can drop into the spinal cord (called __ __..
__ are the classic finding in ependymoma. A true __ is where tumors make a lumen whereas in a ___, the blood vessel makes a lumen.
Genetics Loss of chromosome__ (~__%) and mutation in the ___ gene (~___%) are associated with ependymomas (usually seen in __ __)
Ependymoma:
Incidence: account for %10 of pediatric brain tumors.
Age/gender: children. Male = female
Location: posterior fossa (4th ventricle / cerebellum)
Grading: 1 to 3 (Most are 2).
The tumors are centered in the region of the 4th ventricle and has a nodular, and enhancing pattern. Because they grow within the vetricular system, they can drop into the spinal cord (called drop metastasis).
Pseudorosettes are the classic finding in ependymoma. A true rosette is where tumors make a lumen whereas in a pseudorosette, the blood vessel makes a lumen.
Genetics Loss of chromosome 22q (~25%) and mutation in the NF2 gene (~10%) are associated with ependymomas (usually seen in spinal ependymomas)
Meduloblastoma is a type of ____.
Incidence - Account for ___% of brain tumors in ___
. - Most ___ primary malignant CNS tumor in ___.
Age and gender: ___, more common in ___ ___%)
Location: __ __ (___)
Grading is a ___
They generally grow within midline of __.
The tumor is centered in the ___ ventricle and is __ and ___ (texture) with areas of contrast enhancement.
Medulloblastoma is a primitive tumor with a ___ appearance on histology, due to minimal ___ and high ____.
This is why it looks __.
Genetics:
__ pathway (beta-catenin mutations) accounts for ___% of cases, ____ prognosis
___ pathway (MYC overexpression) ___% of cases, ___ prognosis
Meduloblastoma is a type of PNET
Incidence - Account for 20% of brain tumors in children.
. - Most common primary malignant CNS tumor in children.
Age and gender: children, more common in males - 65%)
Location: posterior fossa (cerebellum)
Grading is a IV
They generally grow within midline of cerebellum.
The tumor is centered in the 4th ventricle and is solid and nodular with areas of contrast enhancement.
Medulloblastoma is a primitive tumor with a blue appearance on histology, due to minimal cytoplasm and high cellularity
This is why it looks blue
Genetics:
WNT pathway (beta-catenin mutations) accounts for 10% of cases, better prognosis
MYC pathway (MYC overexpression) 28% of cases, worse prognosis
Meningiomas:
___ (__) cell neoplasms.
Grow along the __ surface of the __
Incidence: most ___ primary extra-axial tumor
Age and gender: __ (peak incidence __ to ___ years)
More common among ___ (M:F = 2:3)
Location: Most occur over the cerebral convexities
Imaging: Dural-based mass (extra-axial), Contrast enhancing
Grading: ___ to ___, but most are grade __ (close to ___%)
Meningiomas classically have a __ __ on imaging.
__ formation is common in meningioma (circular arrangement of tumor cells). Over time, they will ___ and form ___ bodies.
Genetics: Associated with deletions of ____ ___.
Target is the NF2 gene on 22q12
Multiple meningiomas in patients with NF2
Meningiomas:
Meningtohelial (subarachnoid) cell neoplasms.
Grow along the inner surface of the dura
Incidence: most common primary extra-axial tumor
Age and gender: adults (peak incidence 40 to 70 years)
More common among females (M:F = 2:3)
Location: Most occur over the cerebral convexities
Imaging: Dural-based mass (extra-axial), Contrast enhancing
Grading: I to III, but most are grade I (close to 90%)
Meningiomas classically have a dural tail on imaging.
Whorl formation is common in meningioma (circular arrangement of tumor cells). Over time, they will calcify and form psammoma bodies.
Genetics: Associated with deletions of chromosome 22 Target is the NF2 gene on 22q12 Multiple meningiomas in patients with NF2
Schwannomas:
___ tumors that arise from Schwann cells of _ __.
Incidence: common tumors
Age and gender: ___, Male __ female
Location: Most common intracranial location is the ____ angle -___th cranial nerve - Called “___ __” or “vestibular neuroma”
Grade ___
Schwannoma is an ____ tumor that most commonly arises at the __ angle.
___ __ (hypercellular area)
___ ___ (hypocellular area)
Genetics -___ __ disorder
- Germline mutations in the ___ gene
- Develop ___ ___ schwannomas
- Also get meningiomas and gliomas
Schwannomas:
Benign tumors that arise from Schwann cells of cranial nerves.
Incidence: common tumors
Age and gender: adults, Male = female
Location: Most common intracranial location is the cerebellopontine angle -8th cranial nerve - Called “acoustic neuromas” or “vestibular neuroma”
Grade I
Schwannoma is an enhancing tumor that most commonly arises at the cerebellopontine angle.
Antoni A (hypercellular area)
Antoni B (hypocellular area)
Genetics - autosomal dom disorder
- Germline mutations in the NF2 gene
- Develop bilateral vestibular schwannomas
- Also get meningiomas and gliomas
WHO grading system:
Four Grades:
I - > __ years; curable if completely excised (Benign)
II - > ___ years; tendency to ___ and progress to high grade (L. grade malignancy)
III - __ to ___ years (H. grade malignancy)
IV - equal or ___ than a ___ (H. grade malignancy)
Histological Features of an Aggressive Tumor
- High ____
- Nuclear ____
- High ____ activity
- ____ endothelial proliferation
WHO grading system:
Four Grades:
I - > 5 years; curable if completely excised (Benign)
II - > 5 years; tendency to recur and progress to high grade (L. grade malignancy)
III - 2 to 3 years (H. grade malignancy)
IV - equal or less than a year (H. grade malignancy)
Histological Features of an Aggressive Tumor
- High cellularity
- Nuclear pleomorphism
- High mitotic activity
- ____ endothelial proliferation
Familial Syndromes:
NF1 - ___ and __ ___ (17q11)
NF2 - ___, ____, ___ (22q12),
___ ___ - SEGA (TSC1/2 - 9q34/16p13)
Von Hippel-Lindae - _____ (VHL - 3p25)
__-___ - Gliomas (TP53 - 17p13)
Familial Syndromes:
NF1 - neurofibromas and pilocytic astrocytoma(17q11)
NF2 - ependymoma, meningioma , schwannoma (22q12),
Tuberous sclerosis - SEGA (TSC1/2 - 9q34/16p13)
Von Hippel-Lindae - hemangioma (VHL - 3p25)
li-fraumini - Gliomas (TP53 - 17p13)
Causes of Tumors
- Radiation (ionizing)
Therapeutic radiation increases the risk for CNS tumors ___-fold
Settings: - Radiation for brain or head and neck tumors or from prophylactic radiation for acute lymphocytic leukemia (ALL)
Length of time required __ to ___ years after radiation exposure. Most common tumors caused by radiation are:
- ___
- ___
Immunosuppression can also cause cancer.
- Strongly associated with primary CNS ____
- ____ patients and a 3600-fold increase in risk) –> primary CNS lymphoma
- Transplant patients
- Most are diffuse large B-cell lymphomas - __-__ virus is implicated in most cases
Causes of Tumors
- Radiation (ionizing)
Therapeutic radiation increases the risk for CNS tumors 20-fold
Settings: - Radiation for brain or head and neck tumors or from prophylactic radiation for acute lymphocytic leukemia (ALL)
Length of time required 8 to 10 years after radiation exposure. Most common tumors caused by radiation are:
- meningioma
- glioma
Immunosuppression can also cause cancer.
- Strongly associated with primary CNS lymphomas
- AIDS patients and a 3600-fold increase in risk) –> primary CNS lymphoma
- Transplant patients
- Most are diffuse large B-cell lymphomas - Epstein-Barr virus (EBV) is implicated in most cases
