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Large or giant intracranial aneurysms can simulate brain tumors clinically and radiologically by virtue of their progressive mass effect. Unlike aneurysms from alternative locations, those arising from the distal posterior inferior cerebellar artery (PICA) are uncommon. We report a patient who experienced progressive hemiparesis with magnetic resonance imaging findings suggestive of an infratentorial ependymoma. Intraoperatively, a thrombosed large aneurysm of the distal PICA was unexpectedly encountered. The aneurysm was clipped and the patient did not develop any permanent neurological deficit. This case illustrates the radiological nuances of large aneurysms and infratentorial ependymomas. Three-dimensional contrast-enhanced magnetic resonance angiography can be falsely negative and the importance of the "target" sign is emphasized. One should be cognizant of this possible diagnosis for patients with midline fourth ventricular lesions in order to reduce surgical risk. [ABSTRACT FROM AUTHOR]

Background/Aim: Preoperative devascularization of intracranial meningioma by endovascular embolization has been performed in many institutes over the past 30 years. Advancement in microsurgical techniques and endovascular technology during the period may have offset or magnified the benefit of the procedure. The aim of the present study was to evaluate the effect of preoperative embolization on surgical resection of intracranial meningiomas. Methods: The results of preoperative embolization followed by surgical resection of intrancranial meningiomas at a local neurosurgical unit in Kwong Wah Hospital (KWH) were compared to the results of surgical resection of intracranial meningiomas without preoperative embolization at another local neurosurgical unit in Princess Margaret Hospital (PMH) between 1 January 2000 and 30 June 2003. Results: For convexity meningioma, there was no statistically significant difference in intraoperative blood loss, units of blood transfused or operation time between the embolized group and the non-embolized group. For parasagittal and sphenoid wing meningioma, although the mean tumour volume was larger in the embolized group, there was less intraoperative blood loss and units of blood transfused, and shorter operation time in the embolized group as compared with the non-embolized group. Conclusion: There was no significant effect of preoperative embolization on surgical resection of convexity meningiomas. However, the procedure appeared to be a useful adjunct to surgical resection of parasagittal and sphenoid wing meningiomas. [ABSTRACT FROM AUTHOR]

Objective: To review the result of microsurgical treatment for cerebral aneurysms at Princess Margaret Hospital, Hong Kong, SAR, with the focus on the use of elective temporary clipping (ETC) in reducing intraoperative aneurysm rupture (IOR). Methods: All clinical notes and operation records of patients who had undergone aneurysm-clipping microsurgery from July 1996 to November 2002 were reviewed. Results: In the past 6 years, 148 patients with 150 aneurysms had undergone microsurgical clipping operations. The overall usage rate of ETC was only 25% (38 out of 150) in the present surgical series. Elective temporary clipping was most frequently applied (40%) in treating anterior communicating artery aneurysm. The overall IOR rate was 26% without ETC, versus 8% with ETC, with 18% absolute risk reduction (95% confident interval: 32%-282%) and 70% relative risk reduction, respectively. The numbers needed for treatment was 5.55. The benefit of ETC was most prominently observed in treating anterior communicating artery aneurysm in which the IOR rate was reduced from 42 to 12%, with 30% absolute risk reduction. Among cases of IOR that occurred without prior elective temporary clip application, the mortality rate was 20.7%. For IOR patients with prior elective temporary clip application, there was no mortality. Conclusion: The present study demonstrates that ETC had led to a significant overall reduction in IOR rate and ETC was associated with better clinical outcome. We encourage and recommend the use of ETC in preventing IOR during aneurysm microsurgery. A prospective study will be conducted on the same topic in our hospitals. [ABSTRACT FROM AUTHOR]

Arteriovenous malformation of the anterior cranial fossa is a rare entity and it carries a high rupture rate especially when it is associated with a venous aneurysm. In the present case report, we described a previously well gentlemen who presented to us with such arteriovenous malformation and our subsequent management given to the patient. Published work of this unusual pathology were reviewed, and theories of its histopathogenesis, presentation, management plan and prognosis are discussed. [ABSTRACT FROM AUTHOR]

We present a case of histologically confirmed lipomatous meningioma, the first to our knowledge reported in Hong Kong. A 75-year-old woman presented to us with on and off dizziness for 1 month. Computed tomography (CT) of the brain showed an extra-axial mass lesion containing fat and solid enhancing foci at her right frontal region. The definitive diagnosis could be made preoperatively. Postoperative histological examination of the tumour revealed the diagnosis of lipomatous meningioma. We have reviewed the literature and discussed the diagnostic clues, clinical presentation and pathology of this rare tumour. [ABSTRACT FROM AUTHOR]