Pathophysiology of Meningioma Growth Risks

Facts

1. Environmental Factors

• Radiation: "Important environmental factor is the irradiation of the head and neck region. Meningiomas are frequent in survivors of nuclear disasters, and there is an increased incidence of these tumors in patients who have had iatrogenic diagnostic or therapeutic irradiation." ^{[Tibor, 2017]}
• Smoking and Heavy Metals: "A comprehensive epidemiological study has established a relationship between smoking and occupational exposure to heavy metals."^{[Tibor, 2017]}

2. Hormones

• Menstrual Cycle and Pregnancy: "The fact that tumor growth is usually occurring in the luteal phase (before your period starts) of the menstrual cycle or the second or third trimester of pregnancy when progesterone plasma concentration is higher suggests the role of sex hormones in the mechanism. Somewhat contradicting these arguments, Progesterone Receptor (PR) is expressed not only in meningiomas of females but also in those of males and children." ^{[Tibor, 2017]}
• Contradictions: "The rapid growth of tumor in pregnancy is not an applicable law (does not always occur). Bringing to light the possible role of progesterone in the regulation of brain blood vessel function would facilitate to understand the connection between endocrine mechanisms and vascular changes." ^{[Tibor, 2017]}

3. Damage Based on Tumor Sizes

• "Sometimes a small Meningioma can cause severe symptoms, whereas a large one can be asymptomatic for a long time. The tumor compresses the surrounding structures leading to complaints and Clinical signs. The most frequent symptoms are; headaches, dizziness, focal lesions and Epileptic fits."^{[Tibor, 2017]}
• "Histologically, benign tumors could prove clinically unfavorable or even lethal."

4. Other Tumor Change Possibilities:

A Meningioma may grow during pregnancy but reduce to the size it was before pregnancy at some point after the child is born.^{[Tibor, 2017]}

5. Tumor Growth Issues

• "The compression of Optic Nerve leads to reduced venous return, resulting in a blurry and oedematous papilla on funduscopy. Squeezing of the oculomotor nerve causes a functional deficit of intraocular muscles, anisocoria, pupillary dilatation and absence of light reaction."^{[Tibor, 2017]}
• "Increased intracranial pressure is also accountable for nausea, vomitus, confusion and finally the patient falls into a coma as a consequence of transtentorial herniation and brainstem compression."

6. Tumor Treatment during Pregnancy

"Brain surgery during pregnancy is extraordinarily risky for both mother and child."^{[Tibor, 2017]}

Conclusion

Contents here was information collected from "Epidemiology and Etiology of Meningioma" completed in 2010, and the study from "Pathophysiology of Meningioma Growth in Pregnancy and other Growth Risks" completed in 2017. However, 1) information on an alternate reason tumor may change during pregnancy unrelated to hormones and 2) tumor growth during pregnancy may reduce back to size before pregnancy at some point after the child is born, was not understood in 2010. Both reports were completed by medical research teams in different countries. Both included patients with Neurofibromatosis Type 2 (NF2) and spontaneous Meningioma growth.

The genetics report completed by the Neurofibromatosis team in the United Kingdom "Clinical and molecular predictors of mortality in neurofibromatosis 2: a UK national analysis of 1192 patients" in 2015, monitored change enough in NF2 patients to confirm women with Meningioma are at higher risk of issues than men.

Sources

1. Tibor Hortobagyi, Janos Bencze, et al. DeGruyter "Pathophysiology of Meningioma Growth in Pregnancy and other Growth Risks" (2017)
   Source Link: https://www.degruyter.com/downloadpdf/j/med.2017.12.issue-1/med-2017-0029/med-2017-0029.pdf | DOI | DOI: 10.1515/med-2017-002
2. Wiemels, J., Wrensch, M., & Claus, E. B. (2010). "Epidemiology and Etiology of Meningioma." Journal of neuro-oncology, 99(3), 307-314.
   http://link.springer.com/article/10.1007/s11060-010-0386-3#page-1
3. Hexter, Adam, et al. "Clinical and molecular predictors of mortality in neurofibromatosis 2: a UK national analysis of 1192 patients." Journal of Medical Genetics (2015): jmedgenet-2015.
   Source: http://jmg.bmj.com/content/52/10/699 | DOI: 10.1136/jmedgenet-2015-103290
4. "The risks of radiation exposure related to diagnostic imaging and how to minimise them." BMJ. ;342:d947 (2011)
   http://www.bmj.com/content/342/bmj.d947 | DOI: 10.1136/bmj.d947
5. "Physiological changes in pregnancy" Cardiovascular Journal of Africa.; 27(2): 89-94. (2016 Mar-Apr)
   Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928162/ | DOI: 10.5830/CVJA-2016-021