CNS Tumors (Gianani) Flashcards
TUMORS OF NEUROGLIAL CELLS
A. Tumors of Glial Cells:
Astrocytic tumors:
Astrocytoma
Glioblastoma multiforme
Oligodendroglioma
Ependymoma - choroid plexus papilloma
B. Neuronal Tumors
Ganglioglioma
Gangliocytoma
Central neurocytoma
C. Embryonal Tumors
Medulloblastoma
Most common tumor in the brain
metastatic
tumor that most often metastasizes to the brain
melanoma
glioblastoma multiforme is another name for
astrocytoma grade 4
Ependymoma
choroid plexus papilloma
GERM CELL TUMORS
Teratoma
Craniopharyngioma
TUMORS OF CRANIAL
AND SPINAL NERVES
Schwannoma
Neurofibroma
can occur peripherally too
The terms “intra-axial” and “extra-axial,”
used in radiological descriptions, mean “in brain or spinal cord tissue” and “extrinsic to brain” respectively.
For instance, astrocytoma and oligodendroglioma are intra-axial; meningioma and Schwannoma are extra-axial.
The term anaplasia describes the cellular atypia and loss of differentiation that are associated with malignant tumors.
OLIGODENDROGLIOMA: genetic alteration
1p and 19q codeletion
ATYPICAL TERATOID-RHABDOID TUMOR genetic alteration
Loss of 22q
particularly bad prognosis- see it in infants
MENINGIOMA: genetic alteration
Loss of 22q
NF1
NF1/17q
NS tumors: Plexiform neurofibroma, MPNST, optic and other gliomas
Other tumors: Pheochromocytoma, GIST
cafe au lait spots
NF2
NF2/22q- the gene is merlin
Vestibular and PN shwannoma, meningioma, other brain tumors
(*acoustic schwannoma)
not associated with other tumors
Li- Fraumeni
TP53/17p
Astrocytoma
Breast carcinoma, bone and soft tissue sarcoma
tuberosclerosis
SEGA
Renal AMLs, lung LAM, ** cardiac rhabdomyoma
VHL
VHL/3p
Hemangioblastoma
Renal cell carcinoma, pheochromocytoma
Von Recklinghausen neurofibromatosis (VRNF - Neurofibromatosis type 1-NF1)
one of the most common genetic disorders, is autosomal dominant and is caused by mutations of a gene on chromosome 17q that encodes a protein called neurofibromin.
Neurofibromin is involved in control of cell proliferation and acts as a tumor supressor.
- have a variety of tumors, including * bilateral optic nerve astrocytomas, and plexiform neurofibromas and malignant peripheral nerve tumors.
- café au lait spots of the skin, axillary and inguinal freckles, dysplasia of the sphenoid wing and other skeletal abnormalities, fibromuscular dysplasia of arteries, and other lesions.
DDx of intracranial mass lesion
Infections
- Cerebral abscess
- Toxoplasmosis
- Tuberculosis
Hemorrhage
- Hematoma
- Hemorrhagic metastasis
Neoplasms
- Primary
- Metastatic
Classification- grades of tumors, etc.
Astrocytic Tumors
- Pilocytic Astrocytoma, WHO Grade I
- Diffuse Astrocytoma, Grades II, III, IV
- Other (PXA, SEGA)
Oligodendroglial Tumors can have a variety of grades
Ependymal Tumors can have a variety of grades
Choroid Plexus Tumors
- Papilloma, Carcinoma
Neuronal and Glioneuronal Tumors
- Neurocytoma, Ganglioneurocytoma, Ganglioglioma
3 tumors in the embryonal category
medulloblastoma, PNET, atypical TERATOID-RHABDOID TUMOR
Meningioma
gets a big chunk of the brain tumor pie (MOST COMMON primary non-malignant tumor of CNS)
Dural-based, extra-axial tumor in adults…complete excision…cure
~25 to 30% of CNS tumors.
Arise from meningothelial cells of arachnoid.
More common in women
Most common genetic abnormality…loss of chromosome 22 (22q)…loss of function of protein merlin.
Multiple in NF2 and post radiation
50% sporadic tumors have mutation of NF2 gene
Majority have good prognosis
>90% WHO I (~5% II, ~2% III)
Many histologic types
meningiomas and invasion
Meningiomas can be seen to invade bone and even muscle…does not mean it is malignant
majority are benign but that some can look and behave malignant.
how meningiomas look on histology
In transitional meningiomas, tumor cells are arranged in whorls with hyalinized and calcified centers that are called psammoma (sand) bodies because they resemble tiny grains of sand.
Gliomas
fairly common group of primary brain tumors, include astrocytomas, oligodendrogliomas, and ependymomas.
These tumor types have characteristic histologic features that form the basis for the classification.
- It is no longer thought that these tumors derive from their specific, mature cell types (astrocytes, oligodendrocytes, and ependymal), but rather that they arise from a progenitor cell that preferentially differentiates down one of the cellular lineages.
Many of the tumors typically occur in certain anatomic regions within the brain, with characteristic age distribution and clinical course.
grade 3 meningioma example
anaplastic meningioma
The two major categories of astrocytic tumors are:
- infiltrating astrocytomas
- diffuse astrocytoma (grade II / IV)
- anaplastic astrocytoma (grade III / IV)
- glioblastoma (grade IV / IV)
2) more localized astrocytomas, of which the most common are the pilocytic astrocytomas. (BETTER PROGNOSIS)
Pilocytic Astrocytoma, WHO I
Most frequent glial tumor in children
Cerebellum
- Thalamus, hypothalamus, * optic nerve
Well circumscribed
Solid and cystic
Increased intracranial pressure, cerebellar signs
Slow growth
Overall good prognosis
Diffuse Astrocytoma, WHO II
Ill-defined, infiltrating Any site in CNS > supratentorial (F,T) Seizures, headaches or focal signs Tendency to progress to higher grade Survival ~5-7 years
Glioblastoma (GBM) WHO IV
Most frequent glial tumor in adults Highly malignant Seizures, headaches, focal deficits Supratentorial Survival ~1 year
primary vs 2ndary glioblastoma
can arise denovo or secondary to astrocytomas
best prognosis for glioblastoma
None of the genetic characteristics have specific prognostic significance except for IDH mutations (proneural type tumors)…better prognosis
Oligodendroglioma
Ill-defined, infiltrating Supratentorial, cortical and white matter Frontal in 50-65% Most common in 4th-5th decades Long history of headaches, seizures Frequently calcified WHO II or III Prognosis 6 years II (better prognosis than other gliomas)
histological look of glioblastoma
foci of necrosis with pseudo-palisading of malignant nuclei and endothelial cell proliferation
Oligodendroglioma gene mutations and prognosis
IDH1/IDH2 gene mutations in 90% and portend a better prognosis.
Deletions of chromosome 1p, together with * 19q seen in 80%…with these deletions, patients have consistent long lasting response to chemo and radiation…not so for the others.
oligodengroglioma histologic appearance
fried egg
positive for GFAP protein
Medulloblastoma, WHO IV
Malignant tumor of children
70% under 15 years of age
Posterior fossa, 75% in the vermis
Ataxia and signs of > IP
WHO IV
Tendency to disseminate along subarachnoid space
Prognosis
- 50-70% at 5 years
- (30% in the 1960’)
Medulloblastomas are thought to arise from
stem cells located in the subependymal matrix and the external granular layer (EGL) of the cerebellum.
Medulloblastoma histology
Classic medulloblastoma (the majority) is a highly cellular tumor composed of diffuse masses of small, undifferentiated oval or round cells.
Wright rosettes- groups of tumor cells arranged in a circle around a fibrillary center
Medulloblastoma and malignancy
- highly malignant tumor.
It infiltrates and destroys brain tissue and tends to seed the subarachnoid space and spread along the walls of the ventricles.
Leptomeningeal dissemination occurs more frequently in medullablastoma than any other BT
The CSF shows high protein and low glucose, and contains tumor cells. CSF cytology is used to monitor the spread of the tumor. Extracranial metastases occur rarely, usually after operation or shunting.
Treatment combines resection, to reduce the tumor mass and decompress the fourth ventricle, shunting of the lateral ventricles, radiation of the tumor bed and the entire neuraxis, and intrathecal chemotherapy.
Primary CNS Lymphoma-PCNSL
PCNSL is typically a diffuse large B-cell lymphoma (DLBCL).
The tumors that arise in immunocompromised patients are EBV-positive.
peripheral
Meningeal spread is very common, and some PCNSLs arise in the subarachnoid space.
Corticosteroids induce apoptosis in PCNSL cells that may be so profound that the tumors disappear (vanishing lymphoma).
METASTATIC TUMORS to BRAIN
majority
men- most commonly primary carcinoma of the lung
women- carcinoma of the breast
highest rate of metastasis- melanoma
Ependymoma
Slow growing tumors, children and young adults
Hydrocephalus, >IP, ataxia
3-9% of CNS tumors
Intraventricular, spinal cord
Well circumscribed, but can disseminate
WHO I, II and III
Prognosis
60%(5y) and 48% (10y) II
55%(5y) and 26% (10y) III
tumors that form rosettes in the brain
retinoblastoma
ependymoma
medulloblastoma
Schwannoma
Other names in books:
Neurilemoma, neurinoma, Vestibular or Acoustic Schwannoma
> > in Peripheral nerves, but in CNS > Vestibular branch of 8th
4-6 decades
Solitary (sporadic)
Bilateral in NF2
Benign
