L3 Flashcards
Majority of Tumor of brain are :
Primary
The unique characteristic features of CNS tumors
- do not have morphologically evident premalignant or in situ stages
- Low grade tumors may infiltrate large regions of the brain and may lead to serious clinical deficits
(poor prognosis) - anatomic site of tumor may influence the outcome due to local effects (benign meningioma may cause
cardiorespiratory arrest from compression of medulla) - Even highly malignant tumors of CNS rarely spread outside the CNS
CLASSIFICATION OF INTRACRANIAL TUMORS
• FROM CELLS OF BRAIN (GLIAL, NEURONAL)
• EMBRYONAL (PRIMITIVE) NEOPLASM (MEDULOBLASTOMA)
• FROM OTHER POPULATION OF CELLS IN BRAIN ( LYMPHOID CELLS, GERM CELL)
• FROM MENINGES ( MENINGOTHELIAL CELLS)
• FROM OTHER SITES OF BODY (METASTATIC)
GLIAL TUMORS are:
• ASTROCYTOMA
• OLIGODENDROGLIOMA
• EPENDYMOMA
Diffuse Astrocytoma
1-most common (80%) glioma in adults
2-most common location is cerebral hemisphere
3-most common presenting features are seizure, headache, focal neurologic deficit
astrocytomas are dividedinto three groups
• Diffuse astrocytoma (grade II)
• Anaplastic astrocytoma (Grade III)
• Glioblastoma ( grade IV)
1-poorly defined, gray, infiltrative tumors
2-invaded brain without forming a discrete mass
3- cut surface of the tumor is either firm or soft and gelatinous
4- Cystic degeneration may be present
Grade II and III astrocytomas
1-some areas are firm and white, others are soft and yellow due to necrosis.
2-Cystic degeneration and hemorrhage may be present
3-necrosis (often with pseudopalisading nuclei) or microvascular proliferation.
Glioblastoma ( grade IV )
characterized by:
1-mild to moderate increase in the number of glial cell nuclei
2- variable nuclear pleomorphism.
Grade II astrocytomas ( diffuse )
بالاضافه للمشترك بينه وبين قريد iii
1-show regions that are more densely cellular and have greater nuclear pleomorphism.
2-Mitotic figures are present.
Anaplastic astrocytomas ( grade III)
+ الاشياء المشتركه مع II
• Usually in children
• Common site is cerebellum
• Low grade tumor
– microcytic areas
– Rosenthal fibers
– Eosinophilic granular bodies
Pilocytic astrocytoma
Oligodendroglioma:
-5 - 10 % of glial tumors
-Most common location is cerebral hemispheres (frontal or temporal lobes )
-Usual presentation is seizure / focal neurologic deficit.
• Grades:
II (Well differentiated)
III (anaplastic)
1-infiltrative tumors that form gelatinous, gray masses, and may show cysts, focal hemorrhage, and calcification
2-tumor is composed of sheets of regular cells with spherical nuclei containing finely granular- appearing chromatin surrounded by a clear halo of cytoplasm.
Well-differentiated oligodendrogliomas (grade II)
1-most commonly arise in the brain stem (especially in pons) and also occur in the spinal cord and thalamus.
2-have acquired point mutation in histone H3.
3- These are infiltrative tumors and results in significant neurologic impairment.
Midline Glioma
-tumors occur near the 4th ventricle in first 2 decades
-Spinal cord is the most common location in adults.
-perivascular pseudorosettes (tumor cells are arranged around vessels with an intervening zone containing thin ependymal processes) are more frequently present.
Ependymoma
Neuronal tumors include :
- Central neurocytoma
- Ganglioglioma
- Dysembroplastic neuroepithelial tumors
-accounts for 20% of pediatric brain tumors.
-exclusively occurs in cerebellum.
-It is a highly malignant tumor.
-tumors are densely cellular with sheets of small blue cells
Medulloblastoma
CNS Lymphoma :
• 1 % of intracranial tumors
• Usually in immunosuppressed individual associated with Epstein Barr virus
• Large B cell lymphoma ( most common type)
Germ Cell Tumor
• Age Less than 20 years (in 90% cases)
• Location pineal and Supraceller
• Common type Germinoma
tumors usually solitary originates from arachnoid meningothelial cells?
Meningioma(
>
((when present at multiple sites, especially in association with acoustic neuromas or glial tumors, the possibility of neurofibromatosis type 2 should be considered))
• grow as well defined durabased masses and may compress the brain but do not invade it?
Meningiomas (Grade I)
• have a higher rate of recurrence and
more aggressive local growth. These have increased cellularity and mitotic activity?
Atypical meningioma (Grade II)
• These are highly aggressive tumor with the appearance of a high-grade sarcoma, but retaining
some histologic evidence of meningothelial origin. Mitotic rates are high (>20 mitoses per 10 HPF)?
Anaplastic (malignant) meningioma (Grade III).
Metastatic tumors common sites ?
- Lung
- Breast
- Skin
- Kidney
- Gastrointestinaltract
diverse tumors develop ?
paraneoplastic syndromes that involve the peripheral and/or central nervous systems
mechanism of paraneoplastic syndromes?
development of an immune responsea gainst tumor antigens that cross-react with antigens in the central or peripheral nervous systems.
Paraneoplastic Syndromes ( Subacute cerebellar degeneration ):
• It is associated with destruction of Purkinje cells, gliosis and a mild chronic inflammatory cell infiltrate.
• circulating PCA-1 antibody (anti-Yo) that recognizes cerebellar Purkinje cells.
• This antibody occurs predominantly in women with (ovarian, uterine, or breast carcinoma)
Limbic Encephalitis
-subacute dementia and marked by perivascular inflammatory cuffs, microglial nodules, some neuronal loss, and gliosis
-most evident in the anterior and medial portions of the
temporal lobe (the microscopic picture resembles that of an infectious process).
-ANNA-1 antibody (anti-Hu) that recognizes neuronal nuclei in the central and peripheral nervous systems -ANNA-1 is most commonly associated with small cell carcinoma of the lung
Familial Tumor Syndromes?
Tuberous sclerosis
Von Hippel-Lindau Disease
-autosomal dominant syndrome.
-hamartomas
-benign neoplasms involving the brain and other tissues
-may result from disruption of either TSC1 (which encodes hamartin) or TSC2 (which encodes tuberin)
Tuberous sclerosis
Von Hippel-Lindau Disease
-autosomal dominant disease
-develop hemangioblastomas of the CNS and cysts involving the pancreas, liver, and kidneys
-Hemangioblastomas are most common in the -cerebellum and retina-
-associated with (VHL) tumor suppressor gene that down-regulates hypoxia-induced factor 1 (HIF-1)
