BRAIN TUMORS Flashcards
4 grades of malignancy:
- Grade 1: slow growing, non-malignant tumors, associated with long-term survival. Chance of cure with surgery alone.
- Grade II: relatively slow growing tumors but sometimes recur as high-grade tumors. Low proliferation but infiltrative nature. Malignant or non-malignant.
- Grade III: Malignant tumors, often recur as higher-grade tumors. Post-operative treatments with chemo and radiotherapy are mandatory.
- Grade IV: rapidly reproducing tumors; they are the most malignant ones with aggressive and fast evolution and fatal outcome.
according to whether they are:
- Intra-axial grow inside the brain tissue and infiltrate the brain, and include:
Neuroectoderm
Glia (glioma) Gliomas have an infiltrative growth, but pial boundaries are preserved.
Ependymal
These tumors can be:
A. Delimited: generally not very aggressive tumors but low malignancy ones
- Dysembryoplastic neuroepithelial tumors (DNET) (I°)
- Pilocytic astrocytoma (I°)
- Ganglioglioma and gangliocytoma (I°)
- Pleomorphic xanto-astrocytoma (II°-III°)
- Subependymoma-Ependymoma
B. Infiltrative:
- Fibrillary-protoplasmatic astrocytoma (II°)
- Oligodendroglioma (II°)
- Anaplastic astrocytoma (III°)
- Glioblastoma (IV°)
EXTRA-AXIAL
. Extra-axial grow outside brain tissue but usually compress the brain:
Meninges (meningioma) – Meningiomas have an expansive growth, and if they expand deep enough, they can encase vessels and nerves
Schwann cells
Bone
0-20 years
Medulloblastoma
Cerebellar astrocytoma
Ependymoma
Craniopharyngioma
Optic glioma
Pinealoma
Teratoma
20-40 years
Meningioma
Hemispheric glioma
Pitituary adenoma
Hemangioblastoma
40-60 years
Glioblastoma
Metastasis
Oligodendroglioma
Astrocytoma
Meningioma
Hemangioblastoma VIII cn neurinoma
60-80 years
Meningioma
Glioblastoma
VIII cn neurinoma
Another distinction based on location divides tumors in
- Supratentorial
- Subtentorial/Infratentorial
The tentorium is a dural fold that divides the skull into two parts: the supratentorial that contains the cerebral hemispheres and the subtentorial that contains brainstem and cerebellum.
This concept of supra and infra tentorial tumors is important for the development of brain herniation (see above).
Intracranial tumors – symptoms and signs
Each brain tumor can have all three of these kinds of symptoms, only one, or different combinations of them.
1) Seizures only for supratentorial tumors (no cerebellum, no brainstem). They can be focal or generalized, and are due to abnormal electrical firing of neurons surrounding the tumor
2) Neurological Syndromes depending on brain locations
a. The central Rolandic sulcus is important for motor and sensory functions: if a tumor is inside this part of the brain we can have sensory or motor dysfunction.
b. If the problem is at the level of the hippocampus, memory will be impaired.
c. Frontal lobe tumors will be affecting the higher mental functions (cognitive, emotional, personality, behavior, motivation), but also the production of language (Broca Area on the dominant side, most of the times on the left).
d. Parietal lobe tumor sensorial function impairment; on the dominant side, the parietal lobe also has the Wernicke area language problems.
e. Temporal lobe memory, emotions, primary auditory, and on the dominant side there is Wernicke area again (language!).
f. Occipital lobe visual functions (visual cortex): lesions in any part of the visual pathway vision impairment.
g. Tumors in cerebellum stance, balance, motor coordination, gait problems.
h. Hypophysis tumors hypophysis influences the functioning of several other glands around the body, responsible also for release of many hormones (PRL, GH, ACTH, TSH, LH, FSH), many hormonal symptoms and problems caused by tumors in the hypophysis.
3) Intracranial hypertension see at the beginning (headache, vomiting, papilledema, cognitive dysfunction, behavioral and mental problems, drowsiness coma, HR, RR, BP dysfunctions).
DIAGNOSIS
Angio-MRI
- CT and MRI with contrast (needed because some tumors could not be visible without contrast).
- PET scan
- Digital angiography
MRI
MRI is more sensitive and provides more accurate information. It allows direct imaging of the tumor (size, shape, vascularization), the visualization of edema/brain herniation, ventricular distortion/hydrocephalus
Intra-axial brain tumors - delimited
Pilocytic Astrocytoma (Grade I)
- It originates from astrocytes.
- Benign tumor typical of the pediatric age and not typically found in adults.
- Cystic component + solid component (both visible in the image on the right) + possible pseudocyst + possible calcifications of the solified component.
- Site: cerebellum, brainstem, diencephalon
- In this case surgery is the only treatment and the cure is complete with no symptoms left in these patients
Intra-axial brain tumors - delimited
Ependymoma (Grade II)
- It originates from the ependymal cells typical of the pediatric age (0,2 cases per 100.000/year)
- Dishomogeneous lesion with calcifications, hemorrhages, cysts and necrosis (MIR to the right)
- Site: IV ventricle
- This tumor is located in the 4th ventricle, and when located there it can be responsible for hydrocephalus as it causes an enlargement of the ventricle system located above the tumor (lateral and 3rd ventricles). This ventricular enlargement leads to impairment and neurological symptoms appear very fast and emergency surgery is required.
Intra-axial brain tumors - infiltrative
Grade II Gliomas
- Infiltrative behavior
- One of the most frequent cerebral tumors (10-15% of all astrocytic brain tumors)
- 1,4 cases per 1.000.000/year with 1500 new cases per year in the US
- They most frequently occus between 20 and 40 years of age (60%) but we can see them in all age groups
Atrocytoma (Grade II)
- It originates from astrocytes
- Age: 3rd and 4th decades
- Images show infiltrative behavior: undefined margins compared to healthy surrounding brain tissues. Compression and dislocation of the ventricular system.
- The margins of the tumor are not well delimited When you operate, there are sometimes where you can distinguish the brain parenchyma from tumor tissue but not so easy when in the OR. We use methods to distinguish normal parenchyma from tumor tissue. One of the methods involves the Injection of fluorescin IV in the patient and then using special microscopes you can see the difference between tumor and normal brain.
- The images show a large lesion of the frontal lobe on the left pre-operative MRI. While the post-opertive MRI shows almost complete tumor resection. We call this gross total removal because it is almost complete but some of the tumor cells remain inside the apparently normal brain.
