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
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2
Q

Glial cell–> Astrocyte –> Astrocytoma: Types

A
  • Diffuse, infiltrating (no capsules) – Adults (30+) more common
    1. Diffuse astrocytoma = Grade 2
    2. Anaplastic astrocytoma = Grade 3
    3. Glioblastoma = Grade 4

** age @ biopsy increases w/ grade
** median survival decreases w/ grade

  • Relatively circumscribed – children & young adults
    1. Pilocytic astrocytoma = Grade 1 or 2
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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
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4
Q

Anaplastic Astrocytomas (G-3)

A
  • Atypia,
  • + mitoses
  • increased cellularity
  • Stain w/ Ki67 to detect proliferation
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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
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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
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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
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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
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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
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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
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11
Q

Ependymoma: histology, imaging

A
  • heterogeneous, enhancing, cystic lesion
  • Pseudorosettes:
    • neoplastic ependymal cells cluster around blood vessels (instead of lining ventricles)
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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
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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
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14
Q

Tumors of cranial and paraspinal nerves

A
  1. Schwannomas (neurilemmomas)
  2. Neurofibromas
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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
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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
    1. Whorls and cords
    2. Whorls + psammoma bodies (collections of calcium
    3. 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)