AQP4, aquaporin-4BBB, blood-brain barrierIba1, ionized calcium-binding adapter molecule 1ICA, internal carotid arteryICAM-1, intracellular adhesion molecule-1I/R, ischemia/reperfusionMCAO, middle cerebral artery occlusionMMP-9, matrix metalloproteinase-9.

A 10-year-old boy presented with an intraparenchymal meningioma, which had no attachment to the dura, manifesting as grand-mal seizure. Neurological examination showed no abnormalities. Magnetic resonance (MR) imaging revealed a round, well demarcated mass in the left frontal lobe, which was homogeneously enhanced. The tumor appeared to be intraaxial and caused marked peritumoral white matter edema. At operation, the mass was totally embedded in the frontal lobe and gross total resection was accomplished. The histological diagnosis was meningothelial meningioma with chordoid components in World Health Organization grade I. His postoperative course was uneventful and postoperative MR imaging revealed no residual tumor. Intraparenchymal meningioma should be considered in the differential diagnosis of an intraaxial lesion in a child.

Endovascular thrombectomy (EVT) is the preferred treatment strategy for patients with acute ischemic stroke (AIS). However, clinical outcome and prognosis in patients who undergo EVT in response to AIS with concomitant malignancy have not been fully elucidated. Data of patients with malignancy who underwent EVT at participating institutions between January 2015 and April 2019 were retrospectively analyzed. Patient characteristics, treatment methods, posttreatment strategy, and long-term prognosis were evaluated in 12 patients with prediagnoses of malignancy. Good revascularization (TICI 2b or higher) was achieved in 10 of 12 patients. Among the eight patients who survived more than 2 weeks from onset, four patients showed good clinical outcome [modified Rankin Scale (mRS) <2] at 60 days posttreatment and were able to continue treatment for malignancy. However, seven of eight patients died within a year of EVT (median survival, 83 days) due to progression of malignancy. One-year survival was achieved in only one patient whose etiology of stroke was determined as infectious endocarditis and not Trousseau syndrome. Even after successful revascularization and good short-term clinical outcome, the long-term prognosis after thrombectomy in patients with malignancy was poor. Thrombectomy for concomitant malignancy requires judicious decision, and further studies are necessary to fully elucidate its efficacy.

Despite successful revascularization, reperfusion after prolonged ischemia causes ischemia reperfusion (I/R) injury. Recruitment and activation of neutrophils is thought to be a key event causing I/R injury. We examined whether post-ischemic intra-arterial infusion of liposome-encapsulated hemoglobin (LEH), an artificial oxygen carrier without neutrophils, could reduce I/R injury in a rat transient middle cerebral artery occlusion (MCAO) model. Male Sprague-Dawley rats were subjected to 2-hour MCAO and then were divided into three groups: 1) LEH group (n=7) infused with LEH (Hb concentration of 6g/dl, 10ml/kg/h) through the recanalized internal carotid artery for 2 hours, 2) vehicle group (n=8) infused with saline (10ml/kg/h) in the same manner as the LEH group, and 3) control group (n=9) subjected to recanalization only. After 24-hour reperfusion, all rats were tested for neurological score and then sacrificed to examine infarct and edema volumes, myeloperoxidase (MPO) expression, matrix metalloproteinase-9 (MMP-9) expression and activity, and reactive oxygen species (ROS) production. Compared with the control group and the vehicle group, the LEH group showed a significantly better neurological score and significantly smaller infarct and edema volumes. MPO expression, MMP-9 expression and activity, and ROS production in the LEH group were also significantly lower than those in the control and vehicle groups. The results in the present study suggest that post-ischemic intra-arterial infusion of LEH can reduce I/R injury through reducing the effect of MMP-9, most likely produced by 2 neutrophils. This therapeutic strategy may be a promising candidate to prevent I/R injury after thrombolysis and/or thromboectomy. (246 words) 3

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