Radiation-Induced Meningiomas: A Series of Four Consecutive Patients and a Review of Literature

To assess the clinical outcomes of treatment for radiation-induced meningiomas. Medical records were retrospectively reviewed for all cranial meningioma cases that were diagnosed and/or underwent surgery at our hospital from 2009 to 2016. All radiation-associated meningioma patients constituted the core sample for this study. This series included one female and three male patients, with a mean age of 47.3 ± 16.3 years. The mean preoperative course was < 3 months. The most common symptom was headache (100%) and three patients had alopecia and thin scalp skin. The mean of the age at which they underwent radiotherapy was 18.5 ± 13.7 years. The mean latency period was 19.2 ± 7.4 years. Initial malignancies included two patients with desmoplastic medulloblastomas (13-year-old female, 65 Gy), (11-year-old male, 54 Gy) and a patient with grade II oligodendroglioma treated with 30 Gy. A male patient received low-dose radiotherapy for chronic otitis at 10 years old. Histopathological examinations revealed the following: 1) fibroblastic-grade I, Ki-67 2%-3%, 25.5 years latency; cerebellopontine angle, 2) atypical meningioma grade II, Ki-67 8%, 21 years, frontal; and 3) transitional grade I, Ki-67 3%-4%, 11 years, frontal. The fourth patient had three radiation-induced meningiomas and 27 radiation-induced cavernomas, and was treated using a gamma knife. The mean follow-up period was 34.8 ± 39.4 months. One patient had rhinorrhea and another experienced a cerebrospinal fluid fistula. Both underwent an additional operation. The former died because of meningitis on postoperative day 31. Most radiation-induced meningiomas are low-grade, but they have a high trend of recurrence. Close follow-up and yearly magnetic resonance imaging would minimize the morbidity rate. To reduce fatal complications, surgery should be planned in conjunction with plastic surgeons.