Summary
Brain tumors are masses of abnormal cells within the brain. They can be primary or metastatic, benign or malignant. Common tumors in children are pilocytic astrocytomas, medulloblastomas, ependymomas, and craniopharyngiomas. Adults most often develop glioblastoma multiforme, meningiomas, hemangioblastomas, schwannomas, oligodendrogliomas, and pituitary adenomas. Clinical features and radiological findings vary according to the type, location, and onset of the tumor. Magnetic resonance imaging (MRI) is the primary diagnostic method. Removal of the entire tumor is a prerequisite for remission. The histological grade of the tumor, which is determined postoperatively, is an important factor in determining the prognosis. Malignant tumors usually require additional treatment with radiotherapy and/or chemotherapy.
Astrocytomas (e.g., pilocytic astrocytoma, glioblastoma multiforme), meningiomas, pituitary adenomas, and schwannomas are discussed in separate articles.
Primary brain tumors
- Primary brain tumors arise within the CNS.
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Metastasis
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Drop metastases (intradural extramedullary spinal metastases ) and leptomeningeal metastases can occur. [1]
- Typically present as nodules along the spine and cauda equina that can cause back pain with neurologic symptoms (e.g., limb weakness)
- Can be detected by lumbar puncture
- Primary CNS tumors do not metastasize to organs outside the CNS.
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Drop metastases (intradural extramedullary spinal metastases ) and leptomeningeal metastases can occur. [1]
Pediatric primary brain tumors [2]
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Most pediatric brain tumors are primary.
- Most common type of benign pediatric primary brain tumor: pilocytic astrocytoma
- Most common malignant pediatric primary brain tumor: medulloblastoma
- Brain tumors are the second most common cause of pediatric cancer after leukemia, accounting for approx. 20% of all cases of pediatric cancer.
| Overview of pediatric primary brain tumors [3][4] | |||
|---|---|---|---|
| Tumor | Precursor | Typical location [5] | Typical histology [6] |
| Pilocytic astrocytoma |
| ||
| Medulloblastoma |
|
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| Ependymoma [7] | |||
| Craniopharyngioma [8] |
|
| |
| Pinealoma |
|
| |
In children, most primary brain tumors arise infratentorially, craniopharyngiomas being an important exception.
Adult primary brain tumors [2]
-
Primary brain tumors are less common than brain metastases in adults.
- Most common benign primary brain tumor in adults: meningioma
- Most common malignant primary brain tumor in adults: glioblastoma multiforme
- Primary brain tumors account for approx. 2% of cancer cases in adults.
| Overview of adult primary brain tumors [3][4] | |||
|---|---|---|---|
| Tumor | Precursor | Typical locations [5] | Typical histology [6] |
| Glioblastoma multiforme (WHO grade IV astrocytoma) |
|
| |
| Meningioma |
|
|
|
| Hemangioblastoma |
|
| |
| Schwannoma |
|
| |
| Oligodendroglioma |
|
| |
| Pituitary adenoma [9] |
|
| |
In adults, most primary brain tumors arise supratentorially, hemangioblastomas and schwannomas being important exceptions.
Pilocytic astrocytoma
- See “Pilocytic astrocytoma”.
Medulloblastoma
- Description:: a highly malignant tumor derived from primitive, neuroectodermal tissue [5]
- Epidemiology
- Associated conditions: Turcot syndrome
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Clinical features [10]
- The most common location is the cerebellum → cerebellar defects (e.g., broad-based gait)
- Most tumors arise within the cerebellar vermis (midline) → truncal ataxia
- Invasion or compression of the 4th ventricle → noncommunicating hydrocephalus → features of raised intracranial pressure (e.g., papilledema, vomiting, headache)
- Drop metastases to the spinal cord are common → paraplegia
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Diagnostics [4]
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Imaging: intraparenchymal contrast-enhancing mass [11]
- CT scan: isodense or hyperdense mass
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MRI
- T1: hypointense mass
- T2: isointense mass
- Biopsy: anaplastic small round blue cells that surround a central neuropil (Homer-Wright rosettes) [6]
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Imaging: intraparenchymal contrast-enhancing mass [11]
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Treatment
- Resection
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Adjuvant therapy
- Children ≥ 3 years: chemotherapy and craniospinal radiotherapy
- Children < 3 years: chemotherapy
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Prognosis
- 5-year survival rate: 60–80% [12][13]
- Poor prognostic factors [14]
- Inadequate resection
- Presence of drop metastases
- HER2/neu mutation
Ependymoma
- Description:: a tumor that arises from ependymal cells of the ventricular system
- Epidemiology: peak incidence in children and young adults
- Associated conditions: neurofibromatosis type II
- Clinical features: the 4th ventricle is the most common location in children → noncommunicating hydrocephalus → features of increased intracranial pressure (e.g., papilledema, headache)
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Diagnostics
- Imaging: intra-parenchymal tumor with calcifications and cystic components due to necrosis and/or hemorrhage
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Biopsy
- Perivascular pseudorosettes
- Rod-shaped bodies (blepharoblasts) near the nucleus
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Treatment
- Resection
- Adjuvant radiotherapy
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Prognosis
- Depends on the WHO grade, but usually poor
- Overall 5-year survival rate: 65–90% [15][16]
Craniopharyngioma
- Description: a relatively benign dysontogenetic tumor arising from a remnant of the Rathke pouch (ectodermal derivative)
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Epidemiology
- Bimodal distribution: 5–14 years; second peak at 50–75 years
- Most common childhood supratentorial tumor
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Clinical features: The tumor arises in the suprasellar region and can extend into the intrasellar region. [17]
- Compression of the pituitary gland due to intrasellar extension → hypopituitarism
- Compression of the ventromedial hypothalamic nucleus → hyperphagia and obesity
- Compression of the infundibular stalk → disconnection hyperprolactinemia
- Compression of the optic chiasm → bitemporal hemianopsia
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Diagnostics [8]
- Imaging: suprasellar calcified cyst with a lobulated contour
- Biopsy: cholesterol crystals found in a motor oil-like fluid on gross examination
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Histological variants
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Adamantinomatous (common)
- Reticular epithelial cells
- Frequently associated with calcifications
- Cysts and keratin nodules
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Papillary
- Metaplastic squamous cells
- Calcifications and cysts are rare.
- No keratin nodules
-
Adamantinomatous (common)
- Differential diagnoses: pituitary adenoma
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Treatment
- Resection
- Adjuvant radiotherapy
- In the case of hypopituitarism: hormone replacement therapy
- Prognosis: generally good, with a 10-year survival rate of ∼ 90% [18][19]
Glioblastoma multiforme
- See “Glioblastoma”.
Meningioma
- See “Meningioma”.
Hemangioblastoma
- Description: : a benign, highly vascularized neoplasm
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Epidemiology
- Rare
- Peak incidence: 20–50 years
- Associated conditions: von Hippel-Lindau disease
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Clinical features
- The cerebellum is the most common location → cerebellar defects
- Compression of the 4th ventricle → non-communicating hydrocephalus → features of raised ICP (e.g., papilledema, headache)
- Erythropoietin production by tumor cells → secondary polycythemia
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Diagnostics
-
MRI; : sharply demarcated intra-parenchymal cystic mass with a non-enhancing wall and an enhancing mural nodule in ∼ 60% of cases [20][21]
- T2: hyperintense mass
- T1: hypointense or isointense mass
- Biopsy: thin-walled capillary vessels, densely packed together with scarce parenchyma
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MRI; : sharply demarcated intra-parenchymal cystic mass with a non-enhancing wall and an enhancing mural nodule in ∼ 60% of cases [20][21]
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Treatment
- Resection
- Antiangiogenic therapy
- Prognosis: Recurrence risk is < 20% in sporadic cases. [22]
Schwannoma
- See “Acoustic neuroma”.
Oligodendroglioma
- Description: : a tumor that arises from oligodendrocytes
- Epidemiology
- Clinical features: : the most common location is the cerebral hemisphere (typically the frontal lobe) → seizures, focal neurological deficits, personality changes
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Diagnostics
-
Imaging: intra-parenchymal tumor with calcifications [23]
- CT: hypodense lesion
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MRI
- T1: hypointense or mixed lesions
- T2: hyperintense lesions
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Biopsy [24]
- Cells with a clear cytoplasm and round nucleus (fried egg cells)
- Chicken-wire pattern of capillary anastomoses
- Molecular testing: assessment of 1p/19q codeletion [25]
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Imaging: intra-parenchymal tumor with calcifications [23]
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Treatment
- Resection
- Adjuvant radiotherapy and chemotherapy
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Prognosis
- Recurrence rate ∼ 100%
- 5-year survival rate 50–60%
Pituitary adenoma
- See “Pituitary adenoma”.
Brain metastases
- Epidemiology: most common cause of brain tumors in adults
- Etiology
-
Clinical features: acute or subacute onset of symptoms due to rapid tumor growth
- Seizures
- Focal neurological deficits
- Cognitive deficits
- Headaches
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Diagnostics
-
Imaging: well-circumscribed tumors at the junction of gray and white matter and/or watershed areas of the arterial system [26]
- Large metastases: ring enhancement due to central necrosis
- Small metastases: homogeneous enhancement
- If the primary tumor is unknown: whole-body contrast CT and/or PET scan
- If no primary tumor is found or if the tumor is not surgically accessible: biopsy of the brain metastasis
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Imaging: well-circumscribed tumors at the junction of gray and white matter and/or watershed areas of the arterial system [26]
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Treatment [27]
- Primary therapy
- Limited brain metastases: surgical resection or stereotactic radiosurgery (e.g., Gamma Knife, CyberKnife, proton beam)
- Extensive brain metastases: stereotactic radiosurgery, whole-brain radiation therapy, or chemotherapy
- Glucocorticoids to reduce tumor edema
- Patients with a high primary tumor burden and a poor functional status (Karnofsky score) can be treated palliatively.
- Primary therapy
- Prognosis [28]
Acute management checklist
- Consult neurosurgery and oncology.
- Start VTE prophylaxis. [29]
- Manage increased intracranial pressure (ICP), if present.
- Urgent neurosurgery and anesthesiology consult
- Assess and secure the airway.
- Consider therapeutic hyperventilation.
- Consider dexamethasone in patients with cerebral edema.
- Consider mannitol
- Admission to ICU and ICP monitoring
- Serial neurologic examination
- Admission to neurology or oncology service