[A Rare Case of Radiation-Induced Meningioma that Occurred Only 3 Years and 6 Months after Radiation Therapy for Oligodendroglioma].

We describe an adult case of radiation-induced meningioma(RIM)that was identified within a short interval from the initial treatment for brain tumor. A 45-year-old woman, who had tumor resection followed by radiation therapy for right frontal oligodendroglioma, showed a small enhanced lesion on the right frontal region 3 years and 6 months after the initial radiation therapy. The pathological diagnosis was meningioma(World Health Organization(WHO)grade I)and the Ki-67 labeling index was 3.2%. Most RIMs occur after a long period of time(18.7-24.0 years on average)following radiation therapy. Several studies have suggested that the period before the occurrence of RIM is correlated with both the age of a patient and the radiation dose at the time of radiation therapy. A patient that receives a higher dose of radiation at a younger age has a higher risk of RIM occurrence. In this case, the patient was middle aged;however, she was exposed to a high dose of radiation(54 Gy). High-dose radiation might induce the early onset of RIM. Recently, treatments for glioma have been developed, thus resulting in an increased long-term survival rate among patients. Physicians must pay attention not only to the recurrence of gliomas but also to the occurrence of RIMs.

Is initial unilateral revascularization acceptable in pediatric patients with bilateral moyamoya disease with mild contralateral hemodynamic disturbance?

OBJECTIVE: Although asymmetrical vascular involvement between hemispheres is common in pediatric patients with bilateral moyamoya disease, whether hemispheres with mild vascular changes and hemodynamic impairment require immediate surgical revascularization or whether they can be observed until disease progression remains unclear. The authors evaluated the long-term outcomes of their strategy to initially perform unilateral surgery and withhold surgery to the contralateral hemispheres with mild vascular changes and hemodynamic impairment. METHODS: The authors retrospectively evaluated Japanese pediatric patients (onset age ≤ 15 years) diagnosed with bilateral sporadic moyamoya disease who underwent unilateral revascularization. The authors investigated whether the patient underwent additional collateral surgery and the incidence of ischemic events during follow-up. They also compared visual assessments of arterial spin labeling (ASL) images obtained before initial surgery, before additional contralateral surgery, and at last follow-up. RESULTS: Overall, 30/47 patients (63.8%) experienced progression of hemodynamic impairment in the contralateral hemisphere and underwent additional surgery. The age at initial surgery of the patients who needed additional contralateral surgery was significantly younger than that of the patients who did not require contralateral surgery (mean [SD] 7.0 [3.0] years vs 9.8 [2.6] years, p = 0.002). One patient (age 4 years) developed ischemic stroke before admission for preoperative evaluation 2 months after novel symptom onset, and another patient (age 6 years) experienced ischemic stroke in the contralateral hemisphere while discontinuing antiplatelet agents before surgery; both patients fully recovered from the neurological deficits. In contralateral hemispheres that required additional surgery, the ASL visual assessment scores significantly decreased before the additional contralateral surgery compared to those obtained before the initial surgery (p = 0.008). CONCLUSIONS: In pediatric patients with bilateral moyamoya disease, withholding surgery for hemispheres with mild vascular changes and hemodynamic impairment is generally safe. Younger patients were more likely to experience contralateral progression and require additional surgery, so close follow-up is needed. ASL imaging is useful for detecting and following the progression of hemodynamic impairment in conservatively treated hemispheres.

Ischemic Stroke with Multiple Cerebral Artery Stenosis in a Patient with an Anaplastic Astrocytoma during Bevacizumab Treatment: A Case Report.

It has been reported that bevacizumab, an agent administered as an adjuvant therapy for high-grade gliomas, causes thromboembolic complications. We report a cerebral infarction with newly developed cerebral artery stenosis occurring during treatment with bevacizumab for an anaplastic astrocytoma. A 48-year-old female underwent excision surgery for an anaplastic astrocytoma on the right temporal lobe and received radiation therapy and chemotherapy with temozolomide. Twenty months after the maintenance therapy, treatment with bevacizumab was introduced for tumor recurrence. After the 14th course of bevacizumab at 6 months, 27 months after radiation therapy, the patient began experiencing mild right hemiparesis. Magnetic resonance imaging revealed scattered cerebral infarcts on the left frontal lobe and diffuse cerebral artery stenosis of the bilateral internal carotid artery system both inside and outside the radiation-treated area. Antiplatelet medication was commenced, and there was no recurrence of ischemic stroke. The morphological transition of the cerebral arteries should be carefully monitored via magnetic resonance angiography during post-radiation treatment with bevacizumab.