Factors affecting the risk:
(1) dose of radiation exposure
(2) reason for the exposure
(3) latency (interval between radiation exposure and diagnosis of the meningioma)
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Radiation Dose
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Dose Designation (Harrison et al)
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< 10 Gy
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low
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10 - 20 Gy
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intermediate
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> 20 Gy
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high
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Reasons for the radiation exposure:
(1) treatment of tinea capitis
(2) exposure to radiation event (Hiroshima, Nagasaki)
(3) dental or diagnostic X-rays
(4) treatment of head or neck tumor
Factors affecting the risk of meningioma:
(1) meningiomas tend to occur in the radiation field
(2) exposure during childhood
(3) a higher radiation dose
(4) other stigmata of radiation exposure (alopecia, skin atrophy, poor vascularity), reflecting the dose and the patient's susceptibility
Radiation-induced meningiomas:
(1) may be multiple
(2) may be malignant
(3) may be recurrent
(4) may be clinically aggressive
