• Clinical science

Brain tumors

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, meningiomas, 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 learning cards.

Primary brain tumors

Pediatric primary brain tumors

Pilocytic astrocytoma

Medulloblastoma Ependymoma Craniopharyngioma Pinealoma
Precursor
  • Primitive, neuroectodermal tissue
  • Rathke pouch
Typical location
  • Posterior cranial fossa (infratentorial)
  • Suprasellar region (supratentorial)
Typical histology
  • Perivascular pseudorosettes
  • Large vacuolated cells with round nuclei (fried egg cells)
  • Lymphoid stroma

In children, most primary brain tumors arise infratentorially, craniopharyngiomas being an important exception!

Adult primary brain tumors

Glioblastoma multiforme

Meningioma

Hemangioblastoma

Schwannoma

Oligodendroglioma

Pituitary adenoma

Precursor
  • Arachnoid cap cells
  • Uncertain origin
  • Pituitary adenotrophic cells (typically lactotrophs)
Typical locations
  • Cerebral hemispheres (supratentorial)
    • May cross the midline (butterfly glioma)
  • Extra-parenchymal tumor that can occur in supratentorial or infratentorial regions
  • Cerebellopontine angle (infratentorial)
  • Frontal lobes (supratentorial)
  • Sella turcica (supratentorial)
Typical histology
  • Spindle cells in palisades (Antoni A tissue) alternating with myxoid areas (Antoni B tissue)
  • S-100 positive
  • Large vacuolated cells with round nuclei (fried egg cells)
  • Chicken-wire pattern of capillary anastomoses
  • 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!

References:[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]

Pilocytic astrocytoma

Medulloblastoma

Ependymoma

Craniopharyngioma

Glioblastoma multiforme

Meningioma

Hemangioblastoma

Schwannoma

Oligodendroglioma

  • Description: : a tumor that arises from oligodendrocytes
  • Epidemiology
    • Median age: 40–50 years
  • Clinical features
    • The most common location is the cerebral hemisphere (typically the frontal lobe) → seizures, focal neurological deficits, personality changes
  • Diagnostics
    • Imaging
      • Intra-parenchymal tumor with calcifications
    • Biopsy
      • Cells with a clear cytoplasm and round nucleus (fried egg cells)
      • Chicken-wire pattern of capillary anastomoses
  • Treatment

Pituitary adenoma

Brain metastases