Overview
Primary brain tumors are the most common solid tumor in children and the second-leading overall cause of cancer death (after leukemia). Primary brain tumors are relatively less common in adults but are still the seventh-leading cause of cancer death (after lung, colon, breast, pancreas, prostate, and leukemia). Primary brain tumors are more common in men except for meningiomas. Metastatic cancers are more common than primary brain tumors. Symptoms of brain tumors are usually progressive and persistent since the tumor is constantly growing over time.
CNS tumors are classified according to the WHO grading system from grade 1 to grade 4. Grade 4 tumors are malignant and are usually fatal. Meningiomas are the most common intracranial tumors. The most common brain tumors in adults are gliomas and the most malignant form, glioblastoma multiforme, is the most common malignant CNS tumor.
Tumors of the CNS
| Tumor | Description |
|---|---|
| Astrocytoma | Astrocytes. Low-grade astrocytoma (Grade I/II) and Hi |
| Oligodendroglioma | Myelinating cells of the CNS |
| Ependymoma | Lining of the ventricles |
| Meningioma | Epithelial cells of meninges |
| Medulloblastoma | Cells of the medulla |
| Schwannoma | Myelinating cells of the pNS |
| Metastasis to the CNS |
Location of brain tumors
| Population | Frequency of location |
|---|---|
| Adult | 70% are supratentorial, 30% are infratentorial |
| Children | 70% are infratentorial, 30% are supratentorial |
Frequency of tumors
| Number | Children | Adults |
|---|---|---|
| #1 | Low grade astrocytoma (pilocytic astrocytoma, glioma) | Glioblastoma multiforme (GBM) |
| #2 | Ependymoma | Meningioma |
| #3 | Medulloblastoma | Low grade astrocytoma |
| #4 | Craniopharyngioma and pituitary adenoma | Ependymoma |
| #5 | Ganglioma | Medulloblastoma |
| #6 | Pineal tumor | Schwannoma |
| #7 | Meningioma | Oligodendroglioma |
- Risk factors
- Genetic syndromes: Li Fraumeni syndrome, Neurofibromatosis
- Ionizing radiation
- Age
- Signs and symptoms
- Headaches (worse in the morning)
- Seizures
- Altered mental state (personality change, apathy)
- Focal neurological deficits
Astrocytoma (Gliomas)
The cell of origin for astrocytoma are astrocytes. Astrocytoma may also be referred to as gliomas. There are 4 histological grades of astrocytoma. Low-grade gliomas refer to Grade I and Grade II.
They are the most common tumor in children (Grade I) and adults (Grade IV)
| Grade | Description |
|---|---|
| Grade I | Pilocystic astrocytoma |
| Grade II | Low-grade astrocytoma |
| Grade III | Anaplastic astrocytoma (rapidly progresses to grade IV) |
| Grade IV | Glioblastoma astrocytoma |
- Patient history
- Young (child, young adults)
- History of ionizing radiation
- Family history of brain tumor
- Known cancer syndrome (neurofibromatosis, Li Fraumeni syndrome)
- Signs and symptoms
- Seizures
- Headache on awakening
- Altered mental status (apathy, sluggishness, personality changes, memory loss)
- Posterior fossa or cerebellar mass (common in children): Neck pain, ocular signs and symptoms, dizziness and ataxia
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Biopsy: most accurate test for formal diagnosis
- Treatment of grade I
- Surgical resection
- Observation with serial imaging
- Treatment of grade II
- Surgical resection
- Chemotherapy and radiation
- Prognosis
- Median survival of 7 years
- Grade I may be cured with surgical resection
Glioblastoma Multiforme
Glioblastoma multiform is an aggressive and deadly type of glioma (WHO grade 4 glioma). It is the most common malignant primary CNS tumor accounting for 80% of malignant CNS tumors. Long term survival is (currently) not possible with GBM. Average survival is less than 2 years even with ideal treatment.
More common in men than women. Associated with mutation in EGFR and PTEN.
- Patient History
- Older adults
- History of ionizing radiation
- Family history of brain tumor
- Known cancer syndrome
- Signs and symptoms
- Headache on awakening (bifrontal and asymmetrically lateralized to the side of the tumor)
- Altered mental status
- Focal neurological deficits (cranial nerve palsy, hemiparesis)
- Signs and symptoms are progressive and do not remit
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Solitary ring enhancing lesion (though less likely to enhance compared to lymphoma and metastasis)
- Central necrosis
- Tumor necrosis
- Biopsy: most accurate test for formal diagnosis
- Molecular glioblastoma: Tumors that contain IDH1 (Isocitrate dehydrogenase) gene mutation or MGMT protein regardless of their histology
- Treatment
- Surgical resection (debulking): improve seizures and neurological deficits from tumor pressure)
- Radiation and Chemotherapy (Stupp protocol): Temozolamide and Carnustine (aids absorption of temozolamide) + 60 Gy radiation
- Tumor-treating field (TTF) device: emerging treatment, but very costly and has limited evidence
- Prognosis
- Poor – average survival is less than 2 years
Oligodendroglioma
Oligodendrogliomas originate from oligodendrocytes.
More common in adults. Median age is 35 years. Usually in the frontal lobe.
- Signs and symptoms
- Seizures (majority of patients)
- Headache
- Increased ICP (papilloedema, gait disturbance)
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Biopsy: most accurate test for formal diagnosis
- Treatment
- Surgical resection
- Radiation
- PCV chemotherapy (procarbazine, lomustine/CeeNU, vincristine)
- Prognosis
- Decent
- Tends to recur and become treatment resistant
Ependymoma
Ependymomas originate from the ependymal cells.
This is the 2nd most common primary brain tumor in children. It is also common in adults and is a very common cause of spinal cancer.
- Patient history
- Neurofibromatosis type 1
- Signs and symptoms
- Obstructive hydrocephalus (most common symptom in children)
- Elevated ICP (papilledema, headache, gait disturbances)
- Cauda equina syndrome (common in adults – spinal cancer)
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Biopsy: most accurate test for formal diagnosis
- Treatment
- Surgical resection
- Radiation
- Chemotherapy
- Prognosis
- Decent
- Recurrece rate is high
Meningioma
Meningioma originate from arachnoid cap cells within the arachnoid matter. The are usually slow growing and benign. They may be cranial or spinal, located anywhere arachnoid cap cells are found.
Location of meningiomas
| Location | Frequncy |
|---|---|
| Covexity of the prasagittal region | 20% |
| Sphenoid ridge | 20% |
| Infratentorial | 13% |
| Intraventricular | 5% |
| Tuberculum sellae | 3% |
| Others | 4% |
WHO classification of meningiomas – There are 15 different types of meningiomas
| Grade | Types |
|---|---|
| Grade I | Meningothelial, Fibrous, Transitional, Psammomatous, Angiomatous, Microcystic, Secretory, Lymphoplasmacyte-rich, Metaplastic |
| Grade II | Chordoid, Clear cell, Atypical |
| Grade III | Papillary, Rhabdoid, Anaplastic |
- Patient History
- Female
- Neurofibromatosis type 1
- Signs and symptoms
- Seizures
- Morning headache
- Weakness (due to impingment on local structures)
- Apathy
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Dural tail connecting the tumor to the meninges
- Broad base that abuts the bone or dura
- Calcifications
- Homogenous enhancement
- Biopsy: most accurate test for formal diagnosis
- Preoperative CTA or MRA: since meningiomas can be highly vascular
- Mother-in-law blush: the tumor enhances before the surrounding cortical vessels. Enhancement persists after cortical washout of the contrast.
- Treatment
- Surgical resection
- Chemotherapy is rarely used. VEGF inhibitors may be used in select cases
- Prognosis
- Good
- Recurrence is common
Medulloblastoma
Medulloblastoma likely arises from embryonal cells in the medulla.
Commonly occurs in children.
- Patient History
- Li Fraumeni syndrome
- Signs and symptoms
- Obstructive hydrocephalus (due to compression of the fourth ventricle)
- Headache and vomiting
- Gait issues and stumbling
- Visual changes (diplopia) due to compression of CN VI
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Biopsy: most accurate test for formal diagnosis
- Treatment
- Surgical resection
- Radiation
- Chemotherapy
- Prognosis
- Worse with younger age
- Metastatic disease
Schwannoma
Schwannoma originate from schwan cells. Common on CN VIII (vestibular schwanonoma/acoustic neuroma) in conjunction with NF-2. Presentation depends on the nerve that is affected
- Patient History
- Neurofibromatosis (NF 1 unilateral, NF 2 bilateral)
- Signs and sympoms
- Sensorineural hearing loss and vestibular symptoms for acoustic neuromas
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Biopsy: most accurate test for formal diagnosis
- Treatment
- Surgical resection
- Prognosis
- Good
- Can recur
Pituitary Neoplsm
Pituitary tumors are common and usually cause a variety of symptoms due to mass effect and hormonal abnormalities.
WHO classification of pituitary tumors
| Classification | Description |
|---|---|
| Function | Functioning or nunfunctioning |
| Hormone secretion | Prolactin, growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, follicular stimulating hormone, luteinizing hormone, or a combination |
| Histopathology | Corticotrophs, gonadotrophs, and lactotrophs |
| Imaging characteristic | Microadenoma (< 10 mm), Macroadenoma (> 10 mm) |
Signs and symptoms
| Tumor | Presentation |
|---|---|
| General signs and symptoms | Headaches, visual problems (bitemporal hemianopsia), cranial neuropathies, panhypopituitarism (30%) |
| Prolactin secreting | Amenorrhoea, galactorrhea, impotence, loss of sex-drive. Women tend to present earlier than men. Men tend to have a higher incidence of macroadenomas. |
| Growth hormone secreting tumor | Acromegaly in adults, gigantism in children |
| ACTH secreting tumors | Cushing’s syndrome |
| TSH secreting tumors | Extremely rare. Lead to hyperthyroidism |
| FSH and LH secreting tumors | Infertility, menstrual irregulatiries, and testicular hypertrophy. Precocious tpuberty in children. |
- Associated genetic conditions
- Multiple Endocrine Neoplasia Type 1 (MEN 1)
- Carney’s complex
- Familial Isolated Pituitary Adenomas (FIPA)
- Investigations
- CT-scan: best initial test
- MRI: more accurate than CT
- Isointense
- Enhances with contrast
- Microadenoma < 10 mm
- Macroadenoma > 10 mm
- Biopsy: most accurate test for formal diagnosis
- Differentials for lesions in the sella turcica
- Pituitary carcinoma
- Craniopharyngioma
- Meningioma
- Chordoma
- Rathke’s cleft cyst
- Arachnoid cyst
- Dermoid and epidermoid cyst
- Aneurysm
- Treatment
- Surgical decompression
- Dopamine agonists (cabergoline and bromocriptine) as the first-line therapy for prolactinoma
- Stereotactic radiation for tumors that recur or if it is in the cavernous sinus
Craniopharyngioma
Craniopharyngioma arises from the pituitary stalk. These tend to recur.
More common in children.
- Signs and symptoms
- Headache
- Visual disturbance (bitemporal hemianopsia)
- Endocrine dysfunction (panhypopituitarism)
- Treatment
- Surgical reseciton
Hemangioblastoma
Hemangioblastomas are associated with von Hippel-Lindau disease. They commonly occur in the cerebellum.
- Treatment
- Surgical resection
Metastatic Brain Tumors
Metastases from the brain are commonly from the lung, skin (melanoma), and breast. Brain metastases are more common than primary brain tumors.
- Signs and symptoms
- Seizures
- Focal neurologicla deficits
- Stroke (due to tumor hemorrhage)
- Acute hydrocephalus
- Headache
- Nausea and vomtiing
- Nuchal rigidity
- Photophobia
- Cognitive dysfunction and otor dysfunction
- Investigations
- CT scan and MRI
- CT scan of the chest, adbomen and pelvis with constrast: depending on history and current symptoms to identify a potential primary source of cancer.
- Treatment
- Radiation: mainstay treatmen for brain metastases
- Surgical resection
- Indications for surgical treatment of metastases
- Solitary metastses larger than 3 cm in areas of the brain where damage would be unlikely to result in significant neurological deficit
- Symptomatic lesions e.g. motor deficit
- Lesion causing seizures
- Lesion with an unknown primary to obtain pathologic diagnosis
- Contraindication to surgical treatment of brain metastases
- Highly radiosensitive tumor
- Life expectancy fewer than 3 months
- Multiple lesins in the brain without an apparent overriding single mass
- Poor functional capcaity
- Progressive extracranial disease without other systemic treatment options
- Small incidental brain mets with a lesion outside the brain that can be biopsied for pathology
Spine Metastases
Metastases to the spine are common, accounting for 90% of masses on spinal imaging. They commonly arise from the breast, lung, prostate and kidneys.
- Signs and symptoms
- Lower back pain
- Prominent at night (night pain)
- Exacerbated by weight bearing (instability pain)
- Radiculopathy
- Myelopathy
- Weakness
- Sensory deficits
- Gait disturbances
- Bowel or bladder dysfunction
- Lower back pain
- Investigations
- CT scan: assess structural integrity of the bones
- MRI scan: detailed visualizaiton of the spinal cord to determine extent and level of compression
- Treatment
- Surgery (laminectomy, posterior decompression, tumor resection or stabilization with instrument)
- Radiation therapy
- Chemotherapy
