Meningioma pathophysiology

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Haytham Allaham, M.D. [2]

Overview

Meningioma arises from the arachnoid "cap" cells, which are normally involved in the protection of the central nervous system by forming a thick envelope of meninges around the brain and spinal cord.[1][2][3] The majority of meningiomas are benign. Development of meningioma is the result of multiple genetic mutations The majority of meningioma cases involve a deletion of the neurofibromatosis 2 gene located on chromosome 22. On gross pathology, a gray, well-circumscribed, dome-shaped mass is a characteristic finding of meningioma. On microscopic histopathological analysis, whorled appearance, calcification, and psammoma bodies are characteristic findings of meningioma.[4]

Pathogenesis

  • Meningiomas are the most common benign tumors of the brain. They are also the most common nonglial brain tumors.[5]
  • Meningioma arises from the arachnoid "cap" cells, which are normally involved in the protection of the central nervous system by forming a thick envelope of meninges around the brain and spinal cord.[6]
  • Meningiomas are commonly found in the base of the skull and perivenous sinuses due to the abundance of arachnoid cap cells in these sites. They are usually non-infilterative.[5]
  • The majority of meningiomas are benign (90%), about 6% are atypical, and 2% are malignant.[5]
  • Some meningiomas may be positive for progesterone receptors on histological examination. This can lead to increased tumor size and symptom burden during pregnancy and the luteal phase of the menstural cycle.[5]
  • Meningiomas may possess receptors for platelet derived growth factor, vascular endothelial growth factor (VEGF), glucocorticoid, and epidermal growth factor.[5]
  • The exact pathophysiology of meningioma depends on the histological subtype of the tumor.
  • Meningioma may be located either intradural or extradural along the central nervous system.[7]
  • Meningiomas can be found anywhere in the central nervous system, with its most frequent distribution as follows: parasagittal (20.8%), then convexity (15.2%), and tuberculum sellae (12.8%).[8]
  • A meningioma can be localized in the following areas: sphenoid ridge, olfactory groove, falx, lateral ventriculi, tentorium, the middle fossa, the orbit, the spinal channel, the Sylvian fissure, extracalvarial, multiple localization, the pontocerebral angle, the sphenoidal plane, and the foramen magnum.[8]
  • The characteristics of a meningioma can be determined based on histopathological variables like tumor gradient, histological subtype, proliferative index, and invasiveness of a tumor to the brain.[8]
  • Meningiomas are frequently found attached to the dura surrounding the brain tissue in several locations that include:[1]

Genetics

  • Development of meningioma is the result of multiple genetic mutations.[1]
  • The majority of meningioma cases involve a deletion of the neurofibromatosis 2 gene located on chromosome 22.
  • Other genes involved in the pathogenesis of meningioma include:

Gross Pathology

  • On gross pathology, a gray, well-circumscribed, dome-shaped mass is a characteristic finding of meningioma.[1]


Gross pathology: Cut surface of a resected meningioma[9]

Microscopic Pathology

  • On microscopic histopathological analysis, whorled appearance, calcification, and psammoma bodies are characteristic findings of meningioma.[4]
  • The table below differentiates between the three main groups of meningioma according to WHO histological classification:[2][3][4]
Grade Histologic features Image

Benign (Grade I) meningioma

Less then 4 mitosis/10 HPF, no atypia

Grade 1 Meningioma

Atypical (Grade II) meningioma

Brain invasion, 4 or more mitosis/10 HPF, necrosis, increased cell count, high nucleus:cytoplasm ratio, increased nucleoli size, presence of sheeting

Grade 2 menigioma

Anaplastic (Grade III) meningioma

20 or more mitoses/10 HPF, histology may be similar to carcinoma or sarcoma

Grade 3 menigioma


  • Shown below is a series of microscopic images of different subtypes of meningioma:[4]

References

  1. 1.0 1.1 1.2 1.3 Meningioma. Wikipedia(2015) https://en.wikipedia.org/wiki/Meningioma#cite_note-pmid7731706-9 Accessed on September, 25 2015
  2. 2.0 2.1 Meningioma. Canadian Cancer Society http://www.cancer.ca/en/cancer-information/cancer-type/brain-spinal/brain-and-spinal-tumours/meningioma/?region=mb September, 25 2015
  3. 3.0 3.1 3.2 Meningeoma. Radiopaedia(2015)http://radiopaedia.org/articles/meningioma Accessed on September, 25 2015
  4. 4.0 4.1 4.2 4.3 4.4 Meningioma. Libre Pathology(2015) http://librepathology.org/wiki/index.php/Meningioma#Quick_overview accessed on September, 25 2015
  5. 5.0 5.1 5.2 5.3 5.4 5.5 Gurcay AG, Bozkurt I, Senturk S, Kazanci A, Gurcan O, Turkoglu OF; et al. (2018). "Diagnosis, Treatment, and Management Strategy of Meningioma during Pregnancy". Asian J Neurosurg. 13 (1): 86–89. doi:10.4103/1793-5482.181115. PMC 5820904. PMID 29492130.
  6. Wiemels J, Wrensch M, Claus EB (2010) Epidemiology and etiology of meningioma. J Neurooncol 99 (3):307-14. DOI:10.1007/s11060-010-0386-3 PMID: 20821343
  7. Meningioma. Libre Pathology(2015) http://librepathology.org/wiki/index.php/Meningioma#Quick_overview Accessed on September, 25 2015
  8. 8.0 8.1 8.2 Sumkovski R, Micunovic M, Kocevski I, Ilievski B, Petrov I (2019). "Surgical Treatment of Meningiomas - Outcome Associated With Type of Resection, Recurrence, Karnofsky Performance Score, Mitotic Count". Open Access Maced J Med Sci. 7 (1): 56–64. doi:10.3889/oamjms.2018.503. PMC 6352459. PMID 30740161.
  9. Image courtesy of Dr Dharam Ramnani Radiopaedia(original file "here"). Creative Commons BY-SA-NC


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