40 Questions
What alteration is commonly observed in IDH-mutated tumors?
Loss of function mutations in ATRX
Which enzyme activity is interfered with by the increased production of 2-hydroxyglutarate in IDH-mutated tumors?
Enzymes that regulate gene expression
What is a common genetic alteration found in oligodendrogliomas?
Co-deletion of 1p and 19q chromosomal segments
Which brain region is most commonly affected by midline gliomas?
Pons
What contributes to the immortalization of tumor cells in glioblastomas?
Mutations in the promoter for telomerase
In IDH-mutated tumors, what is uncommonly observed compared to tumors with telomerase mutations?
Promoter mutations for telomerase
What mechanism is involved in preserving telomere length in tumors with loss of function mutations in ATRX?
Alternative lengthening of telomeres
Which system do ependymomas most often arise next to?
Nervous system
Where are medulloblastomas located in children?
In the midline of the cerebellum
What is the most common CNS neoplasm in immunosuppressed individuals?
Primary CNS lymphoma
What percentage of intracranial tumors does Primary CNS lymphoma account for?
1%
What virus are primary brain lymphomas nearly always positive for?
EpsteinBarr virus (EBV)
At what age does the incidence of primary brain lymphoma increase in nonimmunosuppressed populations?
After 60 years of age
What is the color and texture of a medulloblastoma as described in the text?
Gray and friable
How does primary brain lymphoma respond to chemotherapy compared to peripheral lymphomas?
Poorer response
What is a characteristic feature of patients with primary brain lymphoma according to the text?
"Multiple tumor nodules within the brain parenchyma"
What is the main reason that even low-grade lesions in the brain can lead to serious deficits and poor prognosis?
Infiltration of large brain regions
Which type of glioma accounts for about 80% of adult gliomas?
Astrocytomas
What is the most common age group for astrocytomas to occur in adults?
Fourth to sixth decades
Which of the following is a common symptom associated with diffuse astrocytomas?
Headaches
Why do histologic patterns continue to guide treatment of gliomas despite molecular characterization?
Accuracy in predicting prognosis
What can influence the outcome of a neoplasm apart from histologic classification?
Anatomic site
Which type of glioma is classified based on morphologic resemblance to different types of glial cells?
Gliomas
Why do even highly malignant gliomas rarely spread outside of the CNS?
'Seed and soil' hypothesis
What is the principal neurologic manifestation of hemangioblastoma?
Highly vascular neoplasm
Which part of the brain is hemangioblastoma most commonly found in?
Cerebellum
What is the main association of hemangioblastoma in the brain?
Mural nodule
Which feature is characteristic of the neuropathology of chronic traumatic encephalopathy?
Tauopathy
What is the role of primary cilia in brain development according to the text?
Related to posterior fossa development
Which condition is NOT mentioned as typically being affected by hemangioblastomas?
Hypothalamus
In which publication was the role of primary cilia in brain development explored?
Neuron
What type of disorder was mentioned in relation to disruptions in cortical development?
Genetic disorder
What is the characteristic appearance of cortical hamartomas in tuberous sclerosis?
Firmer than normal cortex and potato-like
Which proteins are disrupted in tuberous sclerosis resulting in increased mTOR activity?
TSC1 and TSC2
What is the role of the TSC protein complex in cellular metabolism?
Negatively regulates mTOR activity
Which lesions are extracerebral in tuberous sclerosis?
Renal angiomyolipomas and retinal glial hamartomas
What is the dark color of tumor nodules in metastatic melanoma attributed to?
Presence of melanin
Which cellular features are characteristic of cortical hamartomas in tuberous sclerosis?
Large vesicular nuclei with nucleoli
What is the main disruption caused by loss of TSC1 or TSC2 proteins in tuberous sclerosis?
Upregulation of mTOR activity
What is a characteristic cutaneous lesion associated with tuberous sclerosis?
Angiofibromas
Explore the characteristics of gliomas, tumors of the brain parenchyma, and their impact on brain function and prognosis. Learn about the clinical deficits, resection challenges, and poor outcomes associated with low-grade lesions. Understand how the anatomic site of the neoplasm can affect patient outcomes regardless of histologic classification.
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