Neuro-Oncology I Flashcards
are malignant tumors in the brain more likely primary or metastases?
Metastases
Most common primary sites for metastatic spread to the brain
lung, breast, melanoma, colon, renal carcinoma
Where are most metastatic lesions located?
within the cerebrum
Most Prevalent brain tumor types in adults
- Meningiomas (most common)
- Gliomas (highest mortality rate)
WHO Tumor Classification
I: benign, slow growing, associated with long term survival
II: Relatively slow growing, cells look abnormal under microscope, can come back as higher grades
III: Malignant, spreads into nearby normal parts of the brain
IV: Malignant, spreads into nearby normal parts of the brain
What are gliomas?
Morphologically and biologically heterogeneous group of primary CNS
tumors
What do gliomas arise from?
Arise from precursors of astrocytes or oligodendrocytes –> astrocytomas and oligodendroglioma
Some tumors present with mixed features that include both histologies
Is surgical cure of glioma possible?
not usually
WHO Grade I Glioma
Pilocytic astrocytoma
WHO Grade II Glioma
- low grade astrocytoma
- low grade oligodendroglioma
- low grade oligo-astrocytoma
WHO Grade III
- Anaplastic astrocytoma
- Anaplastic oligodendroglioma
- Anaplastic oligo-astrocytoma
WHO Grade IV
Glioblastoma
Low grade or diffuse astrocytoma (Grade II)
Uncommon, tend to be very slow growing
Found in cerebrum
Tumor progression is highly variable
Surgical resection (plus radiation if incomplete resection)
Anaplastic Astrocytoma (Grade III)
Malignant tumor, typically located in the cerebral hemisphere
Presents with seizure, symptoms of increased intracranial pressure, focal
neurological dysfunction
Surgical resection followed by radiation and chemotherapy
Glioblastoma - Grade IV
Most common primary malignant brain tumor; tumor
cells are undifferentiated
Prognosis is poor
Tumor tends to be localized to the cerebral hemispheres
Classic “butterfly” appearance on imaging
Presents with symptoms of increased intracranial pressure and focal neurological dysfunction
Surgical resection to relieve mass effect, radiation and
chemotherapy
Oligodendroglioma (Grade II or III)
- Primary tumors tend to arise in the frontal lobe or white
matter –> tend to infiltrate the cortex making surgical cure difficult - On imaging, these tumors are not distinguishable from
astrocytomas - Slow growing –> prolonged period of symptoms prior to
diagnosis - Low grade = resectable if in an accessible region of the
brain; if not resectable, controversy over best treatment
What occurs to oligodendrogliomas over time?
low grade tumors transform into anaplastic tumors = death in most patients
What is a meningioma?
Intracranial tumors that arise from meningothelial arachnoid cap cells of the meninges
the majority of Meningiomas are….
benign, slow-growing tumors that compress brain tissue (rarely invade)
Surgical resection is difficult if they invade the sinuses and encase cerebral arteries
Can penetrate bone and present as a scalp mass
Presentation of meningiomas
- Dependent on location
- Focal seizures, neurological deficits from brain and cranial nerve compression
what is the gold standard for meningiomas?
surgery
- if unressectable, radiation is utilized
Presenting signs and symptoms of Brain tumors
- Clinical signs and symptoms of primary brain tumors may be general or focal
- Initial symptoms are often focal –> generalized symptoms as the tumor
increases in size and spreads - General – due to increased intracranial pressure:
Headache: tension type (40-80%) or migraine (10%)
Epileptic seizures
Frontal Lobe
Thought
Reasoning
Behavior
Memory
Parietal Lobe
Sensory Perception
Spatial Relations
Occipital Lobe
Left: Speech, Motion, Sensation
Right: Abstract Concepts
Temporal Lobe
Behavior
Memory
Hearing and Vision Pathways
Emotion
Standard of care for diagnosing brain tumors
MRI of brain
What does an MRI of the brain tell us
- location, extent of involvement, effect of compression
- IV contrast: enhancement of areas that have had disruption of the blood-brain barrier
- Contrast: differentiate between actual primary mass and peritumoral edema
Limitations of MRI
difficulty distinguishing between necrotic tissue and recurrent tumor
When is CT used for diagnosis?
When patients have a contraindication to MRI
What does CT followed by MRI provide?
structural and anatomical characteristics of the intracranial tumors in question
what do MR spectroscopy and PET scans give?
further clues into the nature of intracranial tumors