P- Tumors of the Nervous System Flashcards
What factor has an association with development of intracranial tumors?
- high dose/therapeutic doses of X-irradiation
There is no firm association with:
- environmental carcinogens
- smoking
- virus
- trauma
- low dose, long term irradiation [x-ray or in nuclear plants]
What are the 4 major familial tumor syndromes for nervous system tumors?
- NF1
- NF2
- VHL syndrome
- tuberous sclerosis
Where is a tumor likely to be if there are:
- motor symptoms
- dementia/alheimers
- increased intracranial pressure
- motor cortex or corticospinal tract
- frontal cortex
- pineal region, region of 3rd ventricle or vermis of cerebellum
What is the most likely cell of origin for brain neoplasms?
multipotential stem cells that reside in developing and mature tissue
What factors of nervous system tumors allow for diagnosis and prognosis?
- type of differentiation
2. grade of the neoplastic cells
Where do most intracranial tumors occur in patients over 50 years old?
What are the most common types?
above the tentorium in the cerebrum
High-grade:
- diffusely-infiltrating astrocytomas
- meningiomas
- metastatic carcinomas
- Oligodendrogliomas
Where do the majority of CNS tumors in childhood occur?
What are the most common types?
What is the WHO grade for each type?
Posterior fossa [brainstem and cerebellum]
- pilocytic astrocytoma - 1
- ependymomas- 2,3
- medulloblastomas -4
What are the main primary intradural tumors?
- meningioma
- schwannoma
- neurofibroma
What cells make up meningiomas?
How fast do they grow and how well differentiated are they?
incompletely differentiated meningothelial cells
[external layer of arachnoid]
Slow growing
low grade [epithelioid cells with low N:C ratio]
WHO 1,2,3
What patients are likely to have multiple menigiomas?
Patients with NF2
What age and sex is more affected by meningiomas?
50-70
Women
Where in the CNS are meningiomas most likely to form?
- over cerebral convexities
other locations: base of cerebrum at sphenoid ridges and olfactory grooves
A 50 year old woman come in complaining of headache.
You do a CT and note a well-circumscribed mass attached to the dura. It shows contrast enhancement.
You take a gross section and note a firm, rubbery, lobulated mass.
On histological section you see:
- epithelioid cells that are round/oval with abundant cytoplasm that appear to wind in spiral whorls
- psammoma bodies in the whorl
What type of tumor are you suspicious of?
Meningioma- meningothelial subtype
A 50 year old woman come in complaining of headache.
You do a CT and note a well-circumscribed mass attached to the dura. It shows contrast enhancement.
You take a gross section and note a firm, rubbery, lobulated mass.
On histological section you see:
- elongated cells that appear eliptical with a collagenous ECM that appear to wind in spiral whorls
- psammoma bodies in the whorls
What type of tumor are you suspicious of?
Meningioma - fibroblastic subtype
A 50 year old woman come in complaining of headache.
You do a CT and note a well-circumscribed mass attached to the dura. It shows contrast enhancement.
You take a gross section and note a firm, rubbery, lobulated mass.
On histological section you see:
- epithelioid cells that are round/oval with abundant cytoplasm.
- elongated spindle cells
- whorls with psammoma bodies
What type of tumor are you suspicious of?
Meningioma- transitional variant
What is the most common cytogenetic abnormality in meningiomas?
- Loss of chromosome 22
- NF2 gene mutation in 60% of tumors
What is the prognosis for meningiomas?
Most are WHO grade 1 meaning that they are space expanding masses that do not infiltrate surrounding tissue.
1 = recurrence below 25%
2 = recurrence below 50%
3 = recurrence 50-94%
What type of cell makes a diffusely infiltrating astrocytoma?
What WHO grade are they?
What age is most affected?
It is made of incompletely differentiated glial cells that exhibit partial astrocytic differentiation
-most occur in the cerebrum
WHO 2
It mostly affects people between 20-45 [60%
A 26 year old man comes into the office complaining of seizures, changes in sensation/weakness and speech difficulties.
On CT/MRI you see an ill-defined irregular mass that does NOT enhance with contrast.
Gross: normal gray and white matter are discolored and there is a burred junction
Histology: incomplete, but well-differentiated astrocytic cells with stellate configuration infiltrating normal axons and glial cells. There is NO vascular infiltration, necrosis
or mitotic figures.
What does the patient most likely have? What protein can you stain for to verify your suspicions?
Diffusely infiltrating astrocytoma
Stain for GFAP [glial fibrillary acidic protein] because it is in the cytoplasm of astrocytic cells but NOT epithelial, melanocyte, hematolymphoid
What genetic mutation is common for diffusely infiltrating astrocytomas?
What is the consequence and how can it be used for diagnosis?
What genetic mutation has been reported in over 65% of low grade astrocytomas that progress to grade 4 tumors [glioblastomas]?
- IDH - isocitrate dehydrogenase an enzyme of the Kreb cycle
Normal IDH –> a-ketoglutarate
Mutated IDH–> 2-hydroxyglutarate
2hydroxyglutarate can be detected by magnetic resonance spectroscopy to assess CNS lesions of uncertain type and to manage gliomas
TP53 is mutated in most cases that progress to grade 4 glioblastomas.
What is the mean survival for patients with diffusely infiltrating astrocytomas?
What patients have an improved overall survival?
6-8 years after surgery.
IDH-mutated patients have a better survival than those with IDH wildtype
What name is given to diffusely infiltrating astrocytomas when they are grade 4?
What percent of intracranial neoplasms does it make up?
What age patient is affected?
Glioblastoma is the most frequent PRIMARY brain tumor –12 to 15% of intracranial neoplasms
Affects 45-70 year olds
A woman brings her husband into the hospital. She said over the past 3 months he has begun having seizures, personality changes, and headaches.
You do a CT and note a unilateral irregularly shaped lesion centered in the white matter with a peripheral zone of contrast [high cellularity] enhancement around a dark central area [necrosis].
Gross: irregular, poorly delineated masses with grey, yellow-white, and reddish/brown/green areas.
Histology:
- poorly differentiated glial cells, some with stellate projections
- cells are crowded more centrally
- pleiomorphic nuclei, mitotic figures
- tumor necrosis, microvascular proliferation
What is the likely diagnosis?
What is the prognosis?
Diffusely infiltrating astrocytoma WHO 4
Gross: grey= neoplastic cells, yellow = necrotic, red/green = recent and remote hemorrhage
Histology:
-vascular infilatration and tumor necrosis differentiate WHO2 from WH1O4
Prognosis = less than 1 year
How do primary and secondary glioblastomas differ in terms of presentation and genetics?
Primary= short clinical history, no clinical evidence of low grade precursor lesion.
*amplification of EGFR, loss of chromosome 10
Secondary = younger patients [<45] and progress from a lower grade infiltrating astrocytoma
*TP53 mutation, IDH mutation
A 40-60 year old patient presents with seizures and a headache. He has had a long pre-operative history of neurologic signs and symptoms.
CT shows a mass in the cerebral cortex and subcortical white matter. The lesion has foci of calcification.
Grossly the tumor is greyish-pink and is soft and gelatinous
Histology shows monomorphic round/oval cells that appear to be “fried eggs”. There are few or no mitotic figures.
What is the likely diagnosis and what grade is it?
What would the grade be if there were mitotic figures?
Fried egg = oligodendroglioma
No mitotic figures = grade 2
Mitotic figures = grade 3
What genetic changes are associated with oligodendrogliomas?
- loss of heterozygosity {LOH} on the long arm of chromosome 19 and LOH of the short arm of chromosome 1 [1p and 19q]
- IDH [same as with astrocytomas grade 2,3]
What is the prognosis for oligodendroglioma grade 2 and 3?
What improves prognosis?
Grade 2 = 5-10 years
Grade 3 = 2-7 years
Patients with tumors that have deletion of 1p and 19q have greater survival