Podcast
Questions and Answers
What area of the brain does a cerebellar tumor primarily affect?
What area of the brain does a cerebellar tumor primarily affect?
- Posterior fossa (correct)
- Middle fossa
- Temporal lobe
- Anterior fossa
Which of the following is a characteristic of medulloblastoma?
Which of the following is a characteristic of medulloblastoma?
- Typically benign
- Exclusively cerebellar (correct)
- Rarely affects the brain stem
- Commonly found in adults
A key genetic event in medulloblastoma involves chromosome 17. What is the most common aberration?
A key genetic event in medulloblastoma involves chromosome 17. What is the most common aberration?
- Translocation of chromosome 17
- Loss of the short arm and duplication of the long arm, forming an isochromosome (correct)
- Deletion of the long arm of chromosome 17
- Inversion of chromosome 17
Which genetic subtype of medulloblastoma is associated with a better prognosis?
Which genetic subtype of medulloblastoma is associated with a better prognosis?
What is a typical microscopic characteristic of classic medulloblastoma?
What is a typical microscopic characteristic of classic medulloblastoma?
What is the WHO grade of hemangioblastoma?
What is the WHO grade of hemangioblastoma?
In which location is hemangioblastoma most commonly found?
In which location is hemangioblastoma most commonly found?
What is a typical characteristic of hemangioblastoma?
What is a typical characteristic of hemangioblastoma?
Which genetic condition is associated with hemangioblastomas?
Which genetic condition is associated with hemangioblastomas?
The VHL tumor suppressor gene, often associated with hemangioblastomas, is typically affected in what way?
The VHL tumor suppressor gene, often associated with hemangioblastomas, is typically affected in what way?
What is a notable microscopic feature of hemangioblastoma cells?
What is a notable microscopic feature of hemangioblastoma cells?
Which of the following is NOT typically associated with cerebellar tumors?
Which of the following is NOT typically associated with cerebellar tumors?
Which characteristic is specific to medulloblastoma but NOT to hemangioblastoma?
Which characteristic is specific to medulloblastoma but NOT to hemangioblastoma?
What feature differentiates desmoplastic/nodular medulloblastoma from the classic type?
What feature differentiates desmoplastic/nodular medulloblastoma from the classic type?
Why is genetic analysis increasingly important in the diagnosis of medulloblastoma?
Why is genetic analysis increasingly important in the diagnosis of medulloblastoma?
Flashcards
Cerebellar Tumors
Cerebellar Tumors
Tumors affecting the posterior fossa, involving the brain stem, cerebellar pontine angle, fourth ventricle, and cerebellum.
Medulloblastoma
Medulloblastoma
A WHO Grade IV embryonal neuroepithelial tumor exclusively found in the cerebellum.
Medulloblastoma Microscopic Features
Medulloblastoma Microscopic Features
Classical medulloblastoma shows high cellularity, anaplasia, mitosis, and Homer Wright rosettes.
Medulloblastoma Diagnosis
Medulloblastoma Diagnosis
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Hemangioblastoma
Hemangioblastoma
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Hemangioblastoma Associations
Hemangioblastoma Associations
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Hemangioblastoma Microscopic Features
Hemangioblastoma Microscopic Features
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Study Notes
- The lecture goes over CNS cerebellar tumors, focusing on Medulloblastoma and Hemangioblastoma
- By the end of this lecture, students should identify the most important pathologic characteristics of Medulloblastoma and Hemangioblastoma
Cerebellar Tumors
- Cerebellar tumors affect the posterior fossa
- Cerebellar tumors involve the brain stem, cerebellar pontine angle, fourth ventricle, and cerebellum
- Metastatic lesions to the cerebellum are common
- Medulloblastoma and hemangioblastoma will be covered in this lecture
Medulloblastoma
- This is a WHO Grade IV tumor
- It is an embryonal neuroepithelial tumor
- These are exclusively cerebellar tumors, specifically in the dorsal brain stem
- Medulloblastoma is the most common CNS embryonal tumor
- It typically presents in childhood, accounting for 20% of childhood brain tumors
- Medulloblastoma is highly malignant but radiosensitive
- Classification is based on molecular/genetic and morphologic variants
Microscopic Variants of Medulloblastoma
- Classic medulloblastoma
- Desmoplastic/nodular medulloblastoma
- Medulloblastoma with extensive nodularity
- Large cell/anaplastic medulloblastoma
Medulloblastoma (Classical)
- High cellularity
- Anaplasia
- Mitosis
- Homer Wright rosettes
Genetic Analysis of Medulloblastoma
- According to the WHO classification of CNS tumors, integrated diagnosis relies on histopathologic and molecular/genetic features
- A WHO diagnosis is required for each case
- Molecular subtype and histologic variants are important factors
- The most common cytogenetic aberration is the loss of the short arm of chromosome 17 (17p), coupled with duplication of the long arm, resulting in isochromosome 17q
- The genetic subtype WNT-activated is the rarest molecular subtype at 10%
- WNT-activated has a better prognosis and nuclear B-catenin presence through immunohistochemistry
Hemangioblastoma
- These are WHO Grade 1 tumors
- They are benign, highly vascular, and slow-growing
- They typically affect adults
- They commonly occur in the cerebellum, but also can occur in the brain stem and spinal cord
- Most cases are sporadic, but they can occur in association with Von Hippel-Lindau disease (VHL)
- The VHL tumor suppressor gene is inactivated in both sporadic cases and VHL-associated cases
Hemangioblastoma
- Frontal sections of the cerebellum shows a well circumscribed reddish mass in the vermis, bulging into the fourth ventricle
Hemangioblastoma Microscopy
- Large vacuolated cells
- Thin-walled vessels
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