Brain tumors

Last updated: September 28, 2023

Summarytoggle arrow icon

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. The most common brain tumors in adults are glioblastomas, 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. The histological grade of the tumor is an important factor in determining the prognosis. Removal of the entire tumor is a prerequisite for remission. Malignant tumors usually require additional treatment with radiotherapy and/or chemotherapy.

Meningiomas, pituitary adenomas, schwannomas, and neoplastic meningitis are discussed in separate articles.

Epidemiologytoggle arrow icon

  • Approx. 30% of brain tumors are primary brain tumors, while approx. 70% are metastases.
  • Approx. 40% of primary brain tumors are benign.
  • Sex: > (except meningiomas, which occur more frequently in women) [1]

Epidemiological data refers to the US, unless otherwise specified.

Approachtoggle arrow icon

Initial evaluation [2]

Clinical assessment

Symptom onset in patients with primary brain tumors is usually insidious, while symptom onset in patients with brain metastases is typically acute or subacute.

Diagnostic testing

Overview of MRI findings in brain tumors

Overview of MRI findings in brain tumors

MRI findings
Tumor type Typical location Other findings
Pilocytic astrocytoma [5]
  • Intense, heterogeous contrast enhancement of solid portion; cyst wall typically non-enhancing
  • Round or oval, well-demarcated, contrast-enhancing lesion within a larger, cystic lesion
Anaplastic astrocytoma [6]
  • Variable
Glioblastoma multiforme [7]
  • Variable
Primary CNS lymphoma [8][9]
  • Periventricular
Meningioma [10]
Metastasis [11][12][13]


Principles of treatment

Management should be specialist guided; utilize a multidisciplinary approach and consult a tumor board if available.

Management of complications of brain tumors [2]

See also ”Cancer-related complications” and “Cancer treatment-related complications.”

Certain types of metastatic brain tumor (e.g., melanoma, renal cell carcinoma) are more likely to hemorrhage, but are not an absolute contraindication to therapeutic anticoagulation. [16]

Taper and discontinue perioperative prophylactic medications within 7–10 days of surgery, unless otherwise indicated. [2]

Primary brain tumorstoggle arrow icon


Primary brain tumors arise within the CNS and are classified based on the growth characteristics and cell type from which the tumor arises.

By the spreading potential

Types of brain tumors by growth characteristics
Low-grade brain tumors High-grade brain tumors
Borders Well-defined Poorly-defined
Spreading potential Low High
Recurrence Rare Frequent

By the cell type


Astrocytomatoggle arrow icon


Astrocytomas are neuroepithelial tumors (gliomas) that arise from astrocytes, which are a specific type of glial cell.

Classification of astrocytomas
Grade Type Description Epidemiology Location Prognosis
I Pilocytic astrocytoma
  • Predominantly in children and young adults (< 20 years)
  • Favorable; long-term survival
  • Completely curable with complete surgical resection
  • Median survival: > 10 years
II Diffuse astrocytoma
  • Slow growing, low-grade tumor that has the potential to progress to higher-grade tumors
  • Peak age: 20–40 years of age
  • Cerebral hemisphere
  • Incurable
  • Median survival: 2–12 years
III Anaplastic astrocytoma [22][23]
  • Peak age: 30–50 years of age
  • Incurable
  • Median survival between 18 months and 10 years
IV Glioblastoma multiforme (GBM) [24][25][26]
  • Malignant tumor with rapid growth, abrupt symptom onset, and short disease course (death within weeks)
  • Peak age: 60–70 years of age
  • Most common malignant primary brain tumor
  • Incurable
  • Median survival of 15 months

Pilocytic astrocytoma [27][28][29][30]

  • Description: slow-growing, circumscribed, non-invasive tumor
  • Epidemiology
    • Most commonly affects children and young adults (< 20 years)
    • The most common primary brain tumor of childhood
  • Associated conditions: neurofibromatosis type I
  • Typical location
  • Clinical features
  • Diagnostics
    • MRI findings
      • Well-demarcated cystic lesion
      • Bright contrast-enhancing solid nodule in the wall of the cyst
    • Histopathology
      • Microcysts
      • Bipolar cells; hair-like projections
      • Eosinophilic fibers with corkscrew appearance (Rosenthal fibers)
  • Treatment: Surgical resection
  • Prognosis
    • Favorable prognosis: high rates of long-term survival
    • Curable with complete resection of the tumor
    • Median survival: > 10 years

Optic glioma [31]

Diffuse astrocytoma

  • Description: slow-growing, infiltrative tumor that arises from glial cells in the CNS and has the potential to progress to higher-grade tumors
  • Epidemiology: peak age 20–40 years
  • Location: cerebral hemispheres
  • Clinical features
    • Insidious onset and slow progression of symptoms
    • Initially manifest with nonspecific features such as headaches, seizures
    • Focal symptoms may develop (e.g, progressive paralysis, aphasia)
  • Diagnostics
  • Treatment
    • Complete surgical resection is often not possible. resection until definable margins can be attempted
    • Percutaneous radiotherapy for very diffuse, unresectable tumors
  • Prognosis: incurable; median survival: 2–12 years

Anaplastic astrocytoma [22][23]

Glioblastoma multiforme

Glial fibrillary acidic protein (GFAP) is an important diagnostic marker for astrocytomas; it is almost always positive in glioblastoma multiforme!

Brainstem glioma [38]

Oligodendrogliomatoggle arrow icon

Ependymomatoggle arrow icon

Medulloblastomatoggle arrow icon

Craniopharyngiomatoggle arrow icon

Pineal gland tumortoggle arrow icon

Hemangioblastomatoggle arrow icon

Primary CNS lymphoma (PCNSL)toggle arrow icon

Definition [9][62]

PCNSL is a rare form of extranodal non-Hodgkin lymphoma that affects the CNS (e.g., brain, eyes, spinal cord, CSF).

Epidemiology [9]

Clinical features [9]

Diagnostics [9][63]

Initial evaluation

When present, lymphoma cells in CSF or vitreous fluid may be sufficient to establish a diagnosis of PCNSL. [9]

Additional evaluation [63]

Treatment [9][62]

Glucocorticoids can decrease diagnostic yield in lymphoma. Except in situations of life-threatening increased ICP, avoid glucocorticoid use until diagnostic tissue and fluid samples have been obtained. [9]

Prognosis [9]

  • Variable
  • Typically better than other primary CNS tumors but less favorable than non-CNS lymphomas

Primary brain tumors according to agetoggle arrow icon

Pediatric primary brain tumors [64][65][66]

Overview of pediatric primary brain tumors [47][66][67]
Tumor Precursor Typical location [45] Typical histology [49][68]
Craniopharyngioma [55]
  • Suprasellar region
Pilocytic astrocytoma
  • Rosenthal fibers: eosinophilic fibers with corkscrew-like configuration
  • GFAP positive
Ependymoma [69]
  • Perivascular pseudorosettes: tumor cells that are arranged in a papillary structure around a central blood vessel

In children, most primary brain tumors arise infratentorial, craniopharyngiomas being an important exception.

Adult primary brain tumors [2]

Overview of adult primary brain tumors [47][67]
Tumor Precursor Typical locations [45] Typical histology [49]
Glioblastoma multiforme (WHO grade IV astrocytoma) [70]
Meningioma [71]
  • Arachnoid cap cells
Hemangioblastoma [72]
  • Vascular system origin
Schwannoma [73]
  • Spindle cells in palisades (Antoni A tissue) alternating with myxoid areas (Antoni B tissue)
  • S-100 positive
Oligodendroglioma [41]
Pituitary adenoma [74]
  • Monomorphic, acidophilic or basophilic, polygonal cells arranged in sheets or cords

In adults, most primary brain tumors arise supratentorially, hemangioblastomas and schwannomas being important exceptions.

Brain metastasestoggle arrow icon


Brain metastases are secondary brain tumors due to metastasis of primary malignancies of other organs.


  • Most common cause of brain tumors in adults [11]
  • Rare in children < 14 years of age [75]

Etiology [76]

Clinical features

Diagnostics [2]