Chapter 28: Tumors Flashcards
Which grade of tumor is considered infiltrative?
Grade II
In which decade of life are Grade II, III, and IV Astrocytomas found?
- Grade II: usually 3rd-4th decase
- Grade III: usually 5th decade
- Grade IV: usually 6th decade and beyond
Pilocytic Astrocytomas generally occur during what decades of life?
Where in brain do they typically occur?
- First 2 decades of life
- Cerebellum and floor/walls of 3rd ventricle, occasionally cerebral hemispheres
What grade of tumor is a Pilocytic Astrocytoma?
- I/IV
- Benign
What are the distinguishing morphological characteristics of Pilocytic Astrocytomas?
- Well-circumscribed, often CYSTIC w/ a mural nodule
- Biphasic pattern
- Hair-like cells w/ long bipolar processes
- Rosenthal fibers
- Eosinophilic granular bodies (EGBs)
Which disease predisposes patients to Pilocytic Astrocytomas and due to what?
NF-1 due to functional loss of neurofibromin
Which 3 tumors are part of the Glioma family?
- Astrocytoma
- Oligodendroglioma
- Ependymomas
Most common presenting signs and symptoms of Infiltrating Astrocytomas?
Seizures, headaches, and focal neurologic deficits related to the site of involvement
Which type of infiltrating astrocytoma belongs to the Grade II-IV designation?
Grade II: diffuse astrocytoma
Grade III: anaplastic astrocytoma
Grade IV: glioblastoma (this is malignant)
Among the higher grade astrocytomas, presence of what mutation is associated with a better outcome?
Mutant form of IDH1
Tumor where the predominant neoplastic astrocyte has a brightly eosinophilic cell body from which emanante abundant, stout processes describes what?
Gemistocytic astrocytoma
What is the histologic pattern characteristically produced by Glioblastomas?
Pseudo-palisading: tumor cells collecting along the edges of necrotic regions
Necrosis in glioblastoma often occurs in a ________ pattern in areas of hypercellularity
Serpentine
Which additional features differentiate a glioblastoma from anaplastic astrocytomas?
Necrosis and vascular (glomeruloid type)/endothelial cell proliferation
What characteristic of Glioblastomas is seen on MRI?
Ring-enhacing lesions
Which tumor often crosses the corpus callosum and produces a “butterfly” appearance
Glioblastoma
Contrast ring enhancing lesions, with hypodense central necrosis is characteristic of what kind of tumor?
Glioblastoma
Alterations in what signaling pathway have been found in Pilocytic Astrocytomas?
BRAF signaling pathway
Which brain tumor appears as a cystic mass with a mural nodule?
Pilocystic astrocytoma
Which tumor is most often found in the temporal lobe in children and young adults, usually with a history of seizures?
Pleomorphic Xanthoastrocytoma
What distinguishes a Pleomorphic Xanthoastrocytoma from more malignant types?
What is the grade and prognosis of this tumor?
- Abundant reticulin deposits, absence of necrosis and mitotic activity
- Grade II/IV w/ 5-year survival rate of 80%
What is the most common Brainstem Glioma?
Intrinsic pontine glioma
What is the prognosis of Intrinsic Pontine Gliomas?
Aggressive and short survival (most common brainstem gliomas)
When are Oligodendrogliomas most commonly seen (decades)?
How are they graded?
- Most common in fourth and fifth decades
- Grade II/IV
Where in the brain are Oligodendrogliomas most often seen?
Cerebral hemispheres w/ predilection for white matter
What are the most common mutations seen in Oligodendrogliomas; which have a better prognosis?
- IDH1 and IDH2 (better prognosis)
- 1p19q (favorable prognosis)
- CDKN2A
What are the distinguishing morphological characteristics of Oligodendrogliomas?
- CALCIFICATION
- Perinuclear halos, “fried eggs” and delicate anastomosing capillaries, “chicken wire”
Which features distinguish an Anaplastic Oligodendroglioma (III/IV) from an Oligodendroglioma?
Vascular hypertrophy, necrosis, and nuclear anaplasia
During which decades of life are Ependymomas most commonly seen and where are they most commonly located?
- First 2 decades
- Fourth ventricle = most common site
- Spinal cord = most common for adults
When Ependymomas occurs in adults they are most often associated with what other condition; due to what mutation?
NF2 – due to mutation on chromosome 22
Which chromosome is the NF2 gene found on?
Chromosome 22
Well circumscribed tumors in the brain that often have cysts, focal hemorrhage, and calcification generally describes?
Oligodendrogliomas
What are the 2 seperate subtype of Ependymomas and which is more serious?
- Mesenchymal subtype = younger patients, more likely to develop metastases w/ a worse prognosis
- Second w/ aberrations of large regions of chromosomes, but have better prognosis
A tumor displaying uniform populations of cells w/ round or oval nuclei w/ abundant clumped chromatin and the appearance of perivascular rosettes is often what type?
Ependymoma
Which rosette type found in ependymomas are more diagnostic?
Ependymal rosettes (true rosettes) = MORE diagnostic than perivascular rosettes
What is the grade for most Ependymomas?
Grade II/IV
Which tumor type is often found in the filum terminale of the spinal cord?
Myxopapillary ependymomas
What is a frequent clinical manifestation of posterior fossa ependymomas?
Hydrocephalus (non-communicating) secondary to progressive obstruction of the 4th ventricle
Which location of ependymomas have the worst overall prognosis in children?
- Posteior fossa = worst overall prognosis; 5 year survival is 50%
- Completely resected supratentorial and spinal types are better
Homer-Wright rosettes are most often seen with what 2 brain tumors?
1) Medulloblastoma
2) Neuroblastoma
Choroid plexus papillomas are most often found where in children and adults?
- In children – lateral ventricles
- In adults – fourth ventricle
Who is most often affected by Non-neoplastic Colloid Cysts of the 3rd Ventricle?
What is the clinical manifestation?
- Young adults
- Found attached to roof of 3rd ventricle, can obstruct foramina of Monro = non-communicating hydrocephalus
- Can be rapidly fatal
What is an important clinical symptom of Colloid Cysts of the 3rd Ventricle?
Headache, sometimes positional (worse when standing up)
What is the most common neuronal type of tumor in the CNS?
Common activating mutation?
- Gangliogliomas
- Mutations in BRAF
Gangliomas are typically ________ lesions that present with ______
Gangliomas are typically superficial lesions that present with seizures
Gangliogliomas are most commonly found in the _______ lobe and have a _____ component
Gangliogliomas are most commonly found in the temporal lobe and have a cystic component
Which low-grade neuronal neoplasm is characterized by evenly spaced, round, uniform nuclei and often islands of neuropil?
Central neurocytoma