Radiation-induced meningioma with a 63-year latency period. Case report.

Meningiomas are known to be induced by low-, moderate-, and high-dose radiation therapy, with an average time interval to tumor appearance of 35, 26, and 19 to 24 years, respectively. An inverse relationship is suggested between the dose of radiation given and the time to tumor formation. The authors report a case of a 68-year-old woman who received orthovoltage radiotherapy at 5 years of age for a presumed (nonbiopsy confirmed) right cerebellar tumor and developed multiple meningiomas in the radiation portals 63 years later. Like many radiation-induced meningiomas, the tumor was histologically atypical and multiple in its presentation. This case suggests that previous radiotherapy may confer a low, but life-long, risk for meningioma occurrence.