Martin: 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 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
Among the higher grade glioblastomas, presence of what mutation is associated with a better outcome?
Mutant form of IDH1

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 with central necrosis

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
Which brain tumor appears as a cystic mass with a mural nodule?
Pilocystic astrocytoma

When are Oligodendrogliomas most commonly seen (decades)?
How are they graded?
- Most common in fourth and fifth decades
- Grade II/IV
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
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

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 a frequent clinical manifestation of posterior fossa ependymomas?
Hydrocephalus (non-communicating) secondary to progressive obstruction of the 4th ventricle
Homer-Wright rosettes are most often seen with what 2 brain tumors?
1) Medulloblastoma
2) Neuroblastoma






