Sung-Kyun Hwang

Meningeal hemangiopericytomas: long-term outcome and biological behavior.

BACKGROUND The authors present a retrospective clinical analysis of meningeal hemangiopericytomas. The long-term outcome and biologic behavior, including local recurrence and extraneural distant metastasis, are elucidated. METHOD Clinical records and radiologic findings of 31 cases with meningeal hemangiopericytoma treated at Seoul National University Hospital and Asian Medical Center between 1982 and 1999 were carefully reviewed. The final outcome was determined by direct or phone contact and questionnaire by mail. The duration of follow-up was from 1 to 216 months (mean 77). All patients underwent craniotomy and Simpson Grade I or II resection was possible in 24 patients. Conventional radiotherapy was given in 11 patients (in 5 after total excision and in 6 for residual mass) and stereotactic radiosurgery was conducted in 6 cases. RESULTS Intracranial recurrence was seen in 12 cases (38.7%) and the mean period before the first recurrence was 104 months. The recurrence was at the primary site in 11 cases and diffuse leptomeningeal seeding occurred in the remaining case. The 5-year recurrence free rate was 59.2% and the extent of excision was the significant factor (72.7% in total excision group and 20.8% in the incomplete excision group, p = 0.006). In four patients (12.9%), extraneural metastases developed at an average of 107 months. Six patients died during the follow-up period; however, 2 of these died of unrelated causes. CONCLUSIONS Complete excision is the most important factor in reducing recurrence. However, recurrence may occur even after complete excision. Careful long-term follow-up is mandatory because of the long disease-free interval.

Therapeutic efficacy and safety of TRAIL- producing human adipose tissue-derived mesenchymal stem cells against experimental brainstem glioma

Mesenchymal stem cells (MSCs) have an extensive migratory capacity for gliomas, which is comparable to that of neural stem cells. Among the various types of MSCs, human adipose tissue-derived MSCs (hAT-MSC) emerge as one of the most attractive vehicles for gene therapy because of their high throughput, lack of ethical concerns, and availability and ease of isolation. We evaluated the therapeutic potential and safety of genetically engineered hAT-MSCs encoding the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) against brainstem gliomas. Human AT-MSCs were isolated from human fat tissue, characterized, and transfected with TRAIL using nucleofector. The therapeutic potential of TRAIL-producing hAT-MSCs (hAT-MSC.TRAIL) was confirmed using in vitro and in vivo studies. The final fate of injected hAT-MSCs was traced in long-survival animals. The characterization of hAT-MSCs revealed the expression of MSC-specific cell-type markers and their differentiation potential into mesenchymal lineage. Short-term outcomes included a 56.3% reduction of tumor volume (P < .001) with increased apoptosis (3.03-fold, P < .05) in animals treated with hAT-MSC.TRAIL compared with the control groups. Long-term outcomes included a significant survival benefit in the hAT-MSC.TRAIL-treated group (26 days of median survival in the control group vs 84 days in the hAT-MSC.TRAIL-treated group, P < .0001), without any evidence of mesenchymal differentiation in vivo. Our study demonstrated the therapeutic efficacy and safety of nonvirally engineered hAT-MSCs against brainstem gliomas and showed the possibility of stem-cell-based targeted gene therapy for clinical application.

Feasibility and limitations of endovascular coil embolization of anterior communicating artery aneurysms: morphological considerations.

OBJECTIVE The purpose of this study is to analyze anterior communicating artery (AComA) aneurysm morphology and its relationship to the limitations and feasibility of endovascular coil embolization. METHODS One hundred twenty-three patients were treated with endovascular coil embolization for AComA aneurysms. Aneurysm morphology was classified into six categories according to the projection of the aneurysm (anterior, posterior/superior, or inferior) and neck size (< 4 mm or >or= 4 mm). The following categories were used: Class A1, anterior projection and neck of aneurysm less than 4 mm; Class A2, anterior projection and neck of aneurysm 4 mm or more; Class B1, posterior (superior) projection and neck of aneurysm less than 4 mm; Class B2, posterior (superior) projection and neck of aneurysm 4 mm or more; Class C1, inferior projection and neck of aneurysm less than 4 mm; and Class C2, inferior projection and neck of aneurysm 4 mm or more. Endovascular procedures were categorized as either successful or unsuccessful according to specific criteria. In addition, patients were followed for recanalization. Clinical follow-up data was obtained at discharge and after 6 months and was classified according to the Glasgow Outcome Scale. RESULTS Complete or near complete aneurysm occlusion was observed in 108 (88%) patients, partial embolization was performed in three (2.4%) patients, and embolization was attempted in 12 (9.7%) patients. Successful embolization for AComA aneurysms was performed in 86 out of 123 (70%) patients or 77.5% (86 out of 111 patients) of those patients in whom embolization was possible. Statistical analysis demonstrated that anterior projecting aneurysms were more likely to be successfully coiled than either inferior or posterior/superior directed AComA aneurysms. In addition, inferiorly projecting AComA aneurysms and wide-neck aneurysms had a significantly higher rate of recanalization. CONCLUSION Endovascular coil embolization of AComA aneurysms shows good outcome in our study. Despite advanced modern techniques, there are limitations in the endovascular approach to AComA aneurysms. Consideration of aneurysm morphology may be used to guide approaches in the treatment of AComA aneurysms.

Olfactory neuroblastomas: survival rate and prognostic factor.

Olfactory neuroblastomas are known to be rare and clinically malignant tumors. The authors analyzed the clinical features, long-term treatment outcomes, and prognostic factors related to 21 cases of olfactory neuroblastomas, treated between January 1979 and October 2000, retrospectively reviewed with medical records and radiologic findings. The mean follow-up period was 28.7 months (range 4–178). The extent of tumor was classified according to the UCLA staging system. Statistical analysis for survival was done using the Kaplan–Meier method and the log-rank test. The mean age was 27 years (13–62), the peak incidence occurred in the second decade (8/21, 38%), and the male to female ratio was 13 : 8. According to the UCLA staging system, there were 3 cases of T1, 5 of T2, 6 of T3, and 7 of T4. The 5-year survival rate was 21.3% and the average survival time was 28.9 months. The group (n = 14) undergoing radical surgical resection as the primary modality, registered a higher survival rate than the radiation and chemotherapy group (n = 7), with 2-year survival rates being 76.2% vs. 14.3%, respectively (p = 0.0274). The early stage (T1, T2) groups exhibited a better survival rate than the advanced (T3, T4) groups with 5-year survival rates being 38.1% vs. 9.1%, respectively (p = 0.0336). The mean recurrence free time was 7.8 months (range 1–25). From these findings we could conclude that tumor detection in the early stage, radical surgical resection as the primary treatment modality, and regular follow-up with radiologic evaluation for recurrence or metastasis, represent important factors for an improved outcome.

Aggressive vestibular schwannomas with postoperative rapid growth: clinicopathological analysis of 15 cases.

OBJECTIVE Vestibular schwannomas (VSs) are known to be relatively slow-growing tumors. Some VSs, however, rapidly regrow or recur after surgical resection. Our objective was to investigate the clinicopathological characteristics of these tumors and to elucidate factors that can predict rapid regrowth or recurrence after surgical resection. METHODS Between 1978 and 2000, 29 patients with VS underwent reoperation for regrowth or recurrence at the Department of Neurosurgery in Seoul National University Hospital. Among these patients, 15 experienced rapid VS regrowth or recurrence (annual growth rate, >15 mm/yr). The clinical, radiological, operative, and pathological findings were reviewed. For a comparison of the morphology and proliferative activity, 15 cases of VS were randomly selected as a control group from among the consecutive operative cases with tumor size larger than 4 cm treated between 1991 and 1999. Pathological parameters consisting of cellularity, pleomorphism, mitosis, necrosis, invasion to adjacent tissue, and microvascular proliferation were analyzed. Proliferative indices (e.g., Ki-67 index) also were evaluated. Statistical analyses were performed using Fishers exact test and the analysis of variance test. RESULTS The differences in clinical features between the aggressive VS group and the control VS group were nonspecific. The mean ages at diagnosis were 40.6 years (range, 21-63 yr) and 49.7 years (range, 35-67 yr) (P = 0.438), and the male-to-female ratios were 7:7 and 5:10 (P = 0.462), respectively. The clinical symptoms and signs were similar between the two groups. Radiologically, aggressive tumors at initial presentation had more lobulating contours than those in the control group (7 of 13 cases versus 3 of 15 cases; P = 0.001). In pathological findings, cellularity and pleomorphism were significantly higher than those in the control group (P = 0.001). However, mitosis, necrosis, invasion to adjacent tissue, and microvascular proliferation were not different between the two groups. The proliferative index (Ki-67 index) was higher in the aggressive group than in the control group (2.28 [range, 0.1-8.6] versus 0.59 [range, 0-1.5]; P = 0.034). CONCLUSION VSs presenting with lobulating contour, high proliferative index (Ki-67 index), and high cellularity or pleomorphism require frequent radiological investigation during follow-up to facilitate early detection of regrowth or recurrence.

Long-term outcome of trigeminal neurinomas with modified classification focusing on petrous erosion

BACKGROUND The authors present a retrospective analysis of 29 consecutive patients with trigeminal neurinomas. Modified classification based on the tumor distribution over petrous ridge is suggested to select the optimal surgical approach and to predict the outcome. METHODS Preoperative computed tomography (CT) or magnetic resonance (MR) images were analyzed to measure a long diameter of tumor axis (LD), which divided into middle and posterior fossa and a width of the petrous erosion (PW) by the tumor on axial image. The tumors were classified into four groups (M, tumor confined to middle fossa; Mp, tumor mainly in middle fossa; M = P, tumor equally distributed into both middle and posterior fossa; Pm, tumor mainly in cisternal space of posterior fossa with slender, rarely round extension into Meckels cave), and extent of removal was compared between the groups. Long-term outcomes were based on recurrence-free survival. RESULTS Total removal was achieved in 16 patients including stage operation (55%). Excluding three tumors, which underwent gamma knife for residual tumor, 8 of 10 subtotally removed tumors recurred at 50 months on average. The LD and PW are significantly different among the tumor types. The M = P type is the largest in both parameter, while the M type is the smallest in LD; Pm type is the smallest in PW, respectively. The tumors with equal or lager posterior fossa component (M = P and Pm type) were more difficult to remove totally by single attempt than those with smaller or nil posterior fossa mass (Mp and M type). Also, the corrected PW (PW over the tumor diameter of minor portion) shows a tendency to influence the extent of removal as the relatively narrow PW hindered the total removal. CONCLUSIONS Aggressive attempt for total removal using skull base approach is recommended, especially for those having dominant posterior fossa component and for those having relatively narrow PW.

Endovascular Enterprise stent-assisted coil embolization for wide-necked unruptured intracranial aneurysms

We evaluated the safety and efficacy of stent-assisted coil embolization for wide-necked unruptured intracranial aneurysms (UIA) based on the results observed in consecutive patients in a single center. This study included 116 patients (29 men, 87 women; mean age, 55.4 years) with 121 UIA which were treated by stent-assisted coil embolization from November 2008 to December 2010. A single stent type (Enterprise; Codman & Shurtleff, Raynham, MA, USA) was used. The clinical and radiological results were evaluated. Embolization was successful without complications in 94% of patients. Six patients had procedure-related thromboembolic events, resulting in neurologic symptoms in four patients, and transient angiographically-visible asymptomatic thromboembolism in two patients. Angiographic aneurysm occlusion was complete in 30.5% of patients, with a small neck remnant in 49.5%, and residual contrast filling in 19.8%. Dual antiplatelet agents were given for at least for 6 months. Thromboembolic stroke developed in three patients during follow-up; all occurred after discontinuation of clopidogrel and/or aspirin. Magnetic resonance angiography (MRA) follow-up was performed for at least 6 months. The mean follow-up was 13.4 months (range, 6-34 months). Eight patients (6.6%) demonstrated recanalization on MRA. Recoiling was performed in one patient (0.8%). The other seven patients with minor recanalization were conservatively followed. Enterprise stent-assisted coil embolization for the treatment of UIA appears to be effective and safe. Future studies including controlled prospective trials and careful follow-up are required to assess its indications and efficacy on a long term basis.

A Case of Lateral Medullary Infarction after Endovascular Trapping of the Vertebral Artery Dissecting Aneurysm

We report an unusual case of lateral medullary infarction after successful embolization of the vertebral artery dissecting aneurysm (VADA). A 49-year-old man who had no noteworthy previous medical history was admitted to our hospital with a severe headache. Computed tomography (CT) revealed a subarachnoid hemorrhage, located in the basal cistern and posterior fossa. Cerebral angiography showed a VADA, that did not involve the origin of the posterior inferior cerebellar artery (PICA). We treated this aneurysm via endovascular trapping of the vertebral artery distal to the PICA. After operation, CT revealed post-hemorrhagic hydrocephalus, which we resolved with a permanent ventriculoperitoneal shunt procedure. Postoperatively, the patient experienced transient mild hoarsness and dysphagia. Magnetic resonance image (MRI) showed a small infarction in the right side of the medulla. The patient recovered well, though he still had some residual symptom of dysphagia at discharge. Such an event is uncommon but can be a major clinical concern. Further investigation to reveal risk factors and/or causative mechanisms for the medullary infarction after successful endovascular trapping of the VADA are sorely needed, to minimize such a complication.

The Role of Lumbar Drainage to Prevent Shunt-Dependent Hydrocephalus after Coil Embolization for Aneurysmal Subarachnoid Hemorrhage in Good-Grade Patients

OBJECTIVE To evaluate the role of lumbar drainage in the prevention of shunt-dependent hydrocephalus after treatment of ruptured intracranial aneurysms by coil embolization in good-grade patients. METHODS One-hundred-thirty consecutive patients with aneurysmal subarachnoid hemorrhage in good-grade patients (Hunt & Hess grades I-III), who were treated by coil embolization between August 2004 and April 2010 were retrospectively evaluated. Poor-grade patients (Hunt & Hess grades IV and V), a history of head trauma preceding the development of headache, negative angiograms, primary subarachnoid hemorrhage (SAH), and loss to follow-up were excluded from the study. We assessed the effects on lumbar drainage on the risk of shunt-dependent hydrocephalus related to coil embolization in patients with ruptured intracranial aneurysms. RESULTS One-hundred-twenty-six patients (96.9%) did not develop shunt-dependent hydrocephalus. The 2 patients (1.5%) who developed acute hydrocephalus treated with temporary external ventricular drainage did not require permanent shunt diversion. Overall, 4 patients (3.1%) required permanent shunt diversion; acute hydrocephalus developed in 2 patients (50%). There was no morbidity or mortality amongst the patients who underwent a permanent shunt procedure. CONCLUSION Coil embolization of ruptured intracranial aneurysms may be associated with a lower risk for developing shunt-dependent hydrocephalus, possibly by active management of lumbar drainage, which may reflect less damage for cisternal anatomy than surgical clipping. Coil embolization might have an effect the long-term outcome and decision-making for ruptured intracranial aneurysms.

A case of recurrent subependymoma with subependymal seeding: case report.

Subependymoma is a rare, slow growing, rarely recurrent tumor. We report a case of recurrent subependymoma with subependymal seeding. An intraventricular tumor in the left temporal horn was detected in a 48-year-old female who presented with a 4-year history of dizziness and memory disturbance. Following near total surgical resection, a tumor diagnosis of subependymoma was confirmed by scattered clusters of isomorphic nuclei embedded in a dense fibrillary matrix of glial cell processes. Twenty-six months after surgery, follow-up (F/U) magnetic resonance (MR) imaging revealed tumor recurrence in the previous site which necessitated linear accelerator radiosurgery (LINAC). A further 21 months later, F/U MR imaging showed recurrent, multiple, enhanced, nodular lesions in the enlarged left lateral ventricle for which the patient underwent reoperation. Radiological and operative findings revealed local relapse with subependymal seeding. The pathological finding was similar to that of the previous tumor and compatible with subependymoma. The patient underwent radiation therapy for the residual tumor. This case history suggests that symptomatic residual tumors require close observation even though the clinical course of subependymoma is usually benign.