28 . Tumors Flashcards
Generally, how do metastatic tumors present in the CNS?
- Multiple, well-circumscribed lesions, most often at the grey-white junction.
- Top 3 metastic cancers are: lung, breast and kidney cancers.
Generally, do primary malignant tumors of the CNS metastasize?
- No, they are locally destructive.
- Rarely metastasize.
What are the key cells in the brain that produce tumors?
- Glial cells (astrocytes, oligodendrocytes, ependymal cells); 50%= supports and surrounds neurons
- Neurons (50%)
- Meningothelial cells = surround brain
Astrocytes produce what tumors in kids and adults
- Kids = Pilocytic astrocytoma
- Adults = Glioblastoma (MC CNS tumor in adults)

Oligodendrocytes produce what tumors and in who are they MC in
Oligodendromas = adults

Ependymal cells produce what tumors and in who are they MC in
Ependymomas = children

Neurons produce what tumors and in who are they MC in
Medulloblastomas (from neuroectoderm) = children

Meningothelial cells produce what tumors and in whome?
Meningioma = adult females

Where are brain tumors most common in kids and adults?
- Kids => infratentorial (posterior fosssa): cerebelleum & brainstem
- Adults => supratentorial (above tentorium)

What are the MC brain tumors in children?
MC infratentorial
- Astrocytoma
- Medulloblastoma
- Ependymoma
- Craniopharyngioma
What are the MC brain tumors in adults?
MC supratentorial
- Glioblastoma **
- Meningioma
- Schwannoma
- Oligodendroma
- Hemangioblastoma
- Pituitary Adenoma
If you have a new onset of a seizure in a adult, think ________.
Brain tumor
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 30-40s
- Grade III: usually 50s
- Grade IV: usually 60s +
What are gliomas?
MC group of primary brain tumors: astrocytomas, oligodendrogliomas, ependymomas
Pattern of growth and spread in tumors in CSF
- Most infiltrate extenselively, even if benign, displaying malignant behavior
- Spread via CSF, but even most malignant gliomas RARELY metastasize ouside CSF
What are Pilocytic Astrocytomas?
- Usually occur when?
- Where in the brain do they typically occur?
Low-grade benign tumor of astrocytes that are the MC brain tumor in chidren; slow growing and prognostically favorable
- 0-20 (First 2 decades)
- Cerebellum, floor/walls of 3rd ventricles, between hemispheres

What grade of tumor is a Pilocytic Astrocytoma?
Benign I/IV; they commonly extend into subarachnoid space, but not sign of aggression and optic nerve lesions
What are the distinguishing morphological characteristics of Pilocytic Astrocytomas?
- Well-circumscribed, CYSTIC tumors w/ a mural nodule
- - Biphasic pattern: loose glial cells w cystic changes and dense piloid tissue
- Low cellularity
- - Hair-like cells w/ long bipolar processes
- - Rosenthal fibers = long-standing gliosis
- - Eosinophilic granular bodies (EGBs)

Marker of Pilocytic astronoma
GFAP

what do these findings signify in pilocytic astronomas?

- EGB = PAS + protein drops that mark a slow growing, low grade tumor that is prognostically favorable
- Rosenthal fibers = long standing gliosis
Which disease predisposes patients to Pilocytic Astrocytomas and due to what?
NF-1 (neurofibromatosis 1) due to functional loss of neurofibromin
Most common presenting signs and symptoms of Infiltrating Astrocytomas?
- Seizures
- HA
- Focal neurologic deficits
related to the site of involvement
Infiltrating astrocytoma range from what kind of tumors?
- Grade II/IV: Diffuse astrocytoma
- Grade III/IV: Anaplastic astrocytoma
- Grade IV/IV: Glioblastoma (this is malignant)
Among the higher grade astrocytomas, presence of what mutation is associated with a better outcome?
Mutant form of IDH1
What are Glioblastomas?
Most common primary brain tumor;
Rapidly progressive, Grade 4 malignant tumor of astrocytes the in the cerebral hemispheres.

Where are Glioblastomas located?
Cerebral hemispheres: often cross the corpus callosum and form “butterfly gliomas”, which are necrotic and hemorrhagic

Are glioblastoma primary tumors or secondary?
- Primary: new tumor in older people
- Secondary: progress in younger patients from a lower-grade astronoma.
What mutations are associated with primary and secondary Glioblastomas?
-
Primary Glioblastomas (new tumor that occur in later people):
- EGFR
- PTEN
-
Secondary Glioblastomas (proceeds from a lower grade tumor in younger patients):
- TP53
- IDH1 / IDH2
- (R132H = better prognosis)
What mutation causing secondary Glioblastomas are associated with a BETTER prognosis?
R132H
Glioblastomas
- Histological pattern (3)
- Serpentine pattern of necrosis
- Pseudo-palisading: ⬆︎ in # tumor cells around necrosis
- Vascular/endothelial proflieration that fill vascular lumen, producing a glomeruloid body (ball-like structure) due to ⬆︎ VEGF made by malignant astrocytes

Ring-enhancing lesion on MRI => think ______
Glioblastoma: ring enhancing lesions iwth hypodense central necrosis

Which tumor often crosses the corpus callosum and produces a “butterfly” appearance of hemorrhage and necrosis?

Glioblastoma

Which brain tumor appears as a cystic mass with a mural nodule?
Pilocytic astronoma
When are Oligodendrogliomas most commonly seen (decades)?
How are they graded?
- Malignant tumor in oligodendrocytes that produces a calcified tumor in white matter, usually in the frontal lobe.
- Adults 40-50 YO
- Grade II/IV
Where in the brain are Oligodendrogliomas most often seen?
White matter of cerebral hemispheres (frontal CTX)
What are the most common mutations seen in Oligodendrogliomas; which have a better prognosis?
- IDH1 and IDH2 (better prognosis) = MC
- Loss of 1p19q (favorable prognosis)
- CDKN2A
What are the distinguishing gross/histo morphological characteristics of Oligodendrogliomas?
- Gross Morphology:
- White matter TUMOR!!!
- Well circumscribed, gelatin, grey, CYSTIC and focal hemorrhage
- CALCIFICATION in the CTX (curvilinear or gyriform distribution)
- Histology:
- Perinuclear halos => creating “fried eggs” apperance (Artifact)
- Chicken wire vascular pattern: delicate anastomosing capillaries
Which features distinguish an Anaplastic Oligodendroglioma (III/IV) from an Oligodendroglioma?
- Vascular hypertrophy and necrosis, but keeps geometric vascularity
- Nuclear anaplasia
- Poor prognosis
What are ependymoma tumors?
Grade II/IV malignant tumors of ependymal cells, MC in children (first 2 decades of life = 0-20 YO)
What are the MC sites/ situations for Ependymoma?
- Children = 4th ventricle => hydrocephalus
- Adults = SC central canal
- Neurofibromatosis 2, where NF2 gene is located
When Ependymomas occurs in adults they are most often associated with what other condition; due to what mutation?
Neurofibromatosis 2 – due to mutation of NF2 gene on Chr22
Well circumscribed tumors in the brain that often have cysts, focal hemorrhage, and calcification generally describes?
Oligodendrogliomas
Histology of Ependymoma
- Uniform cells with round-oval nuclei and alot of clumped chromatin
-
Epyndemal (true rosettes = tubular structure w central canal) or perivascular rosettes (ependymal cells project processes towards central BV)
- Ependymal are more diagnositc

Which rosette type found in ependymomas are more diagnostic?
Ependymal rosettes (true rosettes)
How do Grade III/IV Ependymomas present differently?
- Greater cell density and mitosis
- Microvascular proliferation
- Necrosis
- Clear cell variane
Which tumors are the following Rosettes MC in?

- HW (neuropil in middle): medulloblastoma, neuroblastoma, PNET
- Flexner (true = lumen in center): ependymoma, retinoblastoma, Wilms
- Pseudo (vessel in center): astroblastoma and thymoma
What is a frequent clinical manifestation of posterior fossa ependymomas?
Hydrocephalus (non-communicating) due 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 bette
Choroid plexus papillomas (increase CSF) are most often found where in children and adults?
- Children – lateral ventricles
- Adults – 4th ventricle
Clinical symptoms of a Choroid Plexus Papillomas
Obstuctrive hydrocephalus: make CSF

Who is most often affected by Non-neoplastic Colloid Cysts of the 3rd Ventricle?
- Located?
- What is the clinical manifestation?
- Young adults
- Attached to roof of 3rd ventricle, can obstruct foramina of Monro => non-communicating hydrocephalus
- HA (can be positional; worse when standinging) => rapidly fatal

What is the most common malignant embryonal CNS tumor in children?
Medulloblastoma (Grade IV/IV) = poorly differentiated neuroectodermal tumor that ONLY occurs midline in the cerebellum
What are medulloblastomas?
Malignant, poorly-differentiated PNET (peripheral neuroectodermal tumor) brain tumor, usually in children, that grows in the MIDLINE cerebellum => causing truncal ataxia.
In adults => grows more laterally

Medulloblastomas are often located where?
Chilren; Midline of the vermis of the cerebellum => truncal ataxia
Adults = more lateral hemispheres
Medulloblastomas can be divided into what 4 genetic groups?
Which have the best and worse prognosis?
- WNT mutation = best prognosis
- SHH mutation
- Group 3 = worst prognosis
- Group 4