Tumors of CNS Flashcards
1
Q
Tumors of neuroepithelial tissue
A
- glial cells, primitive embryonic cells, nerve cells - neurocytoma, mixed nerve/glial cell tumors
- Glial cell tumors:
- Astrocytes = Astrocytomas
- Oligodendrocytes = Oligodendrogliomas
- Ependymal cells = Ependymomas
2
Q
Glial cell–> Astrocyte –> Astrocytoma: Types
A
- Diffuse, infiltrating (no capsules) – Adults (30+) more common
- Diffuse astrocytoma = Grade 2
- Anaplastic astrocytoma = Grade 3
- Glioblastoma = Grade 4
** age @ biopsy increases w/ grade
** median survival decreases w/ grade
- Relatively circumscribed – children & young adults
- Pilocytic astrocytoma = Grade 1 or 2
3
Q
Astrocytomas (G-2):
A
Histology:
- No mitoses
- Atypia: irregular, hyperchromatic nuclei
- Embedded in fibrillary network
CT/Gross features:
- Non-enhancing, poorly-demarcated lesion
- can cause midlline shift, expansion/distortion of normal structures as it invades cerebrum
4
Q
Anaplastic Astrocytomas (G-3)
A
- Atypia,
- + mitoses
- increased cellularity
- Stain w/ Ki67 to detect proliferation
5
Q
Glioblastoma (G-4)
A
- Atypia, + mitoses
- Pseudopallasading necrosis
- Vascular proliferation
- neovascularization w/ endothelial proliferation
- forming glomeruloid tufts
- can grow in deep gray matter meaning that there may be few symptoms and patient may die from brain herniation
- Genetics:
- EGFR – assoc w/ primary GBM
- TP53, IDH1/2 – assoc w/ secondary GBM
- IDH assoc w/ better prognosis
6
Q
Pilocytic astrocytoma: epi and prognosis
A
- Children, young adults
- Cerebellum, optic nerve/pathway, or hypothalamic region
- not infiltrative
- rarely progress to anaplastic form
- better prognosis
- quiescent for many years
- if it does recur, it will come back w/ same grade
- more easily resected
- BRAF fusion oncogene = common mutation
7
Q
Pilocytic astrocytoma: histology
A
- Cystic lesion w/ enhancing
- Biphasic pattern:
- Compact
- cystic/spongy
- Eosinophilic granular bodies in cystic area
- Rosenthal fibers
- intense pink/eosinophilic elongated bundles on H&E,
- thought to be intermediate filaments
- highly associated w/ this type of tumor
- Moderate cellularity
8
Q
Oligodendroglioma: epi and prognosis
A
- Grade 2
- Diffuse, infiltrating, well-differentiated tumor
- Some can appear relatively well-circumscribed though
- Present as single lesions
- Young to middle aged adults
- This tumor will eventually progress to Grade 3 variant and kill the patient –> may take years
9
Q
Oligodendroglioma: histology and genetics
A
- Genetics:
- loss of heterozyogcity of 1p and 19q (80% of cases)
- Favorable prognosis –> live longer, better response to chemo
- “Fried egg” appearance of hypercellular oligos
- “Chicken wire” = branching capillary vessels
10
Q
Ependymoma: epi and prognosis
A
- Children and young adults
- Prognosis better for young adults
- Common locations: (in order)
- 4th ventricle, Spinal cord
- Lateral ventricle, 3rd ventricle
- Spinal ependymomas more common in 20-40yo pt
- Grade 2
11
Q
Ependymoma: histology, imaging
A
- heterogeneous, enhancing, cystic lesion
- Pseudorosettes:
- neoplastic ependymal cells cluster around blood vessels (instead of lining ventricles)
12
Q
Medulloblastoma (Embryonal tumors): epi, location
A
- Children
- Grade 4
- Location:
- Cerebellum, midline/vermis
- Extension into 4th ventricle
- Contrast enhancing tumor
- Well-circumscribed
- Solid, cystic or nodular
- Soft, gelatinous or firm
- Small foci of necrosis
- Calcification
13
Q
Medulloblastoma: histology, genetics
A
- Origin: granule neurons
- densly packed cells w/ round to ovoid nuclei
- mitoses frequent
- necrosis may be present
- high N/C ratio
-
Homer Wright rosettes
- 40% of cases
- sign of neuronal differentiation
- Staining: antibody to neurofilament protein
- Genetics:
- Myc amplification via Wnt, Shh, other mutations
-
Group 3 = i17q (2 identical long arms)
- highest Myc amplification
- most aggressive,
- high frequency of metastatic disease
- poorest response to therapy
14
Q
Tumors of cranial and paraspinal nerves
A
- Schwannomas (neurilemmomas)
- Neurofibromas
15
Q
Schwannoma
A
- Schwann cells
- Slow growing, benign - Grade 1
- Occur on cranial and spinal nerve roots
- Most common = CN8 –> Cerebellopontine angle
- Compress nerves
- Patients w/ NF2 may have bilateral acoustic/vestibular (CN8) schwannoma
- Histology = biphasic
- Antoni A = compact w/ spindled cells in fascicles
- Antoni B = loose meshwork of cells w/ mucous-like background
16
Q
Neurofibroma
A
- Cell type: non-myelinating schwann cells (cover smaller diameter axons)
- Location:
- Dermal –> skin nodules
- Intraneural (peripheral nerves) in solitary nerves or nerve plexi
- Multiple neurofibromas and/or neuromas in nerve plexi = pt has NF1
- Benign
- difficult to resect bc of location at nerve roots
- Histology: haphazardly arranged cells, wavy nuclei
17
Q
Tumor of meninges: Meningiomas
A
- From cells of pia and arachnoid (leptomeninges)
- incidence increases w/ age
- more frequent in females
- associated with NF2 (50% of NF2 pt may develop meningiomas)
- Evenly-enhancing lesion on imaging
- Benign histologically
- resection may be difficult depending on location
- some stay small and do not cause symptoms
- Location: skull base, areas w/ arachnoid granulations
- Histology = Grade 1, benign
- Whorls and cords
- Whorls + psammoma bodies (collections of calcium
- Fibrous
18
Q
Metastatic tumors
A
- Lung, breast, skin, kidney, colon –> parenchyma
- Prostate –> dura, leptomeninges
- lymphomas, leukemias –> meninges or bone
- Often multiple
- Ring-enhancing lesions
19
Q
Incidence: overall, age, gender
A
- Primary CNS neoplasms =
- 2% of all malignant neoplasms
- 20% of children’s cancer
- Bi-modal age distribution
- Children (medulloblastoma, pilocytic astrocytoma)
- Adults, 45-70 (GBM, metastatic, meningioma, schwannoma)
- Gender:
- Males –> gliomas, embryonal
- Females –> meningiomas
20
Q
Etiology
A
- Most primary tumors are sporadic
- <5% are assoc w/ hereditary syndromes
- NF1 - neurofibromas, meningioma
- NF2 - schannoma, meningioma, ependymoma
- Tuberous sclerosis - astrocytoma subtype
- Gorlin syndrome, Turcot syndrome - medulloblastoma
- Ionizing radiation
- *** Meningiomas (e.g. children tx for medulloblastoma)
- Other: astrocytomas (e.g. children tx for ALL), nerve sheath tumors
- Immunodeficiency
- Primary CNS Lymphomas
21
Q
Epilepsy – common tumors
A
- Astrocytomas
- oligodendrogliomas
- Involving motor cortex or temporal lobes
22
Q
Focal neurological deficit – common tumors
A
- tumors growing in specific areas
- internal capsule
- motor cortex
- visual cortex
- optic chiasm
- cerbellum
- Hemiplegia, aphasia, loss of vision, cerebellar dysfunction, hypothalamic-pituitary dysfunction
23
Q
Mental status changes – comon tumors
A
- Gliomas involving hippocampus, amygdala
- mimic psychosis like schizophrenia
- frontal lobe neoplasms
- deep apathy, depression
24
Q
Obstructive hydrocephalus – common tumors
A
- tumor arising from area around aqueduct or 3rd ventricle
- e.g. pineal gland
- protruding into 4th ventricle
- e.g. medulloblastoma, ependymoma
- occluding foramina of monroe
- e.g. astrocytoma subtype assoc w/ tuberous sclerosis
25
Q
Transtentorial herniation
A
- “Uncal” herniation – if only this part is involved
- Can also be bilateral
- may compress the PCA
- Duret hemorrhages:
- in brainstem
- secondary to the herniation
- due to stretching/tearing of brainstem vessels
- Nerve compression
- CN3
- cerebral peduncle
- Abducens nerve against the petrous part of temporal bone (in other types of herniation too)
