CNS Tumors Flashcards
In gliomas, we see amplification of
EGFR
In an astrocytoma, we see loss of tumor suppressor genes
TP53 and ATRX
In a glioma, we see the loss of the tumor suppressor gene
-better prognosis
IDH
An example of epigenetic gene silence is seen in a glioblastoma with
MGMT hypermethylation
An example of a tumor caused by persistent activation of gene mutation product is seen in gliomas with
EGFRvIII
An example of a tumor caused by chromosomal abnormality is seen in an oligodendroglioma with the co-deletion of
1p19q
Radiation causes an increase in the incidence of
Meningiomas
May induce mesenchymal and glial tumors
Nitroso compounds
Mostly arise in the cerebellum and hypothalamus
-seen most commonly in children and young adults
Pilocytic Astrocytoma
Has a bihasic histological pattern and rosenthal fibers on histological staining
Pilocytic Astrocytoma
Pilocytic astrocytomas are characterized as being
GFAP positive
Tumor most frequently seen in cerebral hemispheres
- usually a poorly demarcated lesion
- commonly in children and young adults
Diffure Astrocytoma
Histologically, shows atypical cells infiltrating in a diffuse fashion and large cells with eosinophilic cytoplasm (gemistocytic astrocytoma)
Diffuse astrocytoma
The most mlignant glioma
-most frequently in middle aged adults
Glioblastoma
Glioblastomas are most commonly in the
Frontal and temporal lobes
A poorly defined mass with heterogenous appearance
Glioblastoma
Characterised by increased cellularity, nuclear atypia, mitosis, vascular endothelial hyperplasia, and necrosis
Glioblastoma
Cause of glioblastoma with better chemosensitivity
MGMT gene promoter hypermethylation
Insidious and slow growing tumors mostly in cerebral hemispheres
-Usually in middle aged adults
Oligodendroglioma
The types of oligodenrogliomas that are chemosensitive solid tumors are due to a co-deletion of
1p and 19q
More circumscribed than astrocytoma
Oligodendroglioma
Tumor cells are uniform with “fried egg” appearance
Oligodendroglioma
An oligodendroglioma is classified as grade II or III (Anaplastic) if there is marked
Mitosis, vascular endothelial proliferation, and necrosis
Some oligodendrogliomas have an astrocytic component. These are called
Oligoastrocytomas
Oligodendrogliomas are positive for
Oligo-2
Tumor frequently in ventricles causing hydrocephalus
-predominantly in children and adolescents
Ependymoma
An ependymoma in the spinal cord and filum terminale
Myxopapillary Ependymoma
Characterized as being exophytic and well demarcated
Ependymoma
Grade III ependymoma characterized by more mitoses, vascular endothelial hyperplasia and necrosis
Anaplastic Ependymoma
Ependymomas are positive for
GFAP, MAP2, and EMA
Greyish, friable mass, commonly in the ventricles
-Mostly in adults
Central neurocytoma
Composed of round uniform cells with scanty cytoplasm
-WHO grade II tumor
Central Neurocytoma
A central neurocytoma is positive for
Synaptophysin and chromogranin
Associated with cortical malformation
-Presents with a history of chronic epilepsy
Ganglioglioma
Cystic tumor with calcified mural node
-Common in children
Ganglioglioma
Typically a Grade I tumor and is rarely a higher grade
Ganglioma
Most frequent malignant tumor in children
- Tumor of cerebellum
- solid and ill-defined
Medulloblastoma
Highly cellular, small oval or round cells with neuronal, glial and other differentiations and neuronal rosette formation
Medulloblastoma
Medulloblastoma is characterized as a grade
IV tumor
A curcumscribed mass attached to the dura
-most common in adult women
Meningioma
Basic histology: pseudointranuclear inclusion, whorl, psammomatous calcification
Meningioma
Meningiomas are positive with
EMA and PR
Tumor of the cerebellum associated with von Hippel Lindau disease
-occur in young to middle aged adults
Hemangioblastoma
Histological characteristics: Numerous delicate capillaries set in a background of clear foamy cells
Hemangioblastoma
A hemangioblastoma is positive with
Inhibin, CD31, and CD34
Suprasella solid and cystic mass
-most frequently seen in children and adolescents
Craniopharyngioma
Histological characteristics: Squamoid cells and keratin with loose connective tissue stroma
- CKs positive
- Grade I tumor
Craniopharyngioma
Most common secretory tumor
- Suprasella
- Most common in adults
- More common in females
Pituitary adenoma
What percentage of pituitary adenomas are non-secretory?
20%
Histological characteristics: Sheets of uniform cells with round nuclei with delicate chromatin
-Positive in synaptophysin, chromogranin, NSE, and hormone (if secretory)
Pituitary adenoma
Extracranial malignancy often demarcated from brain tissue
-morphologically similar to primary extracranial tumor
Metastatic neoplasm
Associated with a gene mutation
-neoplasm and non-neoplasm
Tumor predisposition syndromes (Phakomatoses)
Characteried by neurofibromin negatively regulating the Ras onco-protein
Neurofibromatosis Type I (NF1) (von Recklinghausen’s disease)
The mechanism is via Merlin which involves cellular proliferation
Neurofibromatosis Type II (NF2)
Mechanism is via VHL protein which activates Hypoxia Inducible Factor (HIF)
Von Hippel Lindau Syndrome
Mechanism is through Hamartin or Tuberin which negatively regulates mTOR protein in a kinase signaling pathway involved in regulation of energy, metabolism and mRNA translation as a tumor suppressor
Tuberous Sclerosis Complex (TSC)
