Subependymoma in the lateral ventricle manifesting as intraventricular hemorrhage.

A 32-year-old man presented with subependymoma in the lateral ventricle causing intraventricular hemorrhage and manifesting as severe headache and disturbance of consciousness. Computed tomography on admission showed a massive intraventricular hemorrhage and acute obstructive hydrocephalus. Cerebral angiography revealed no abnormal findings. Emergency external ventricular drainage was performed, and his neurological deficits gradually improved. Magnetic resonance imaging at 5 weeks after admission showed a tumor arising from the septum pellucidum or the floor of the right lateral ventricle, appearing as a mixed-intensity solid tumor, which was partially enhanced following gadolinium administration. The tumor had arisen from the septum pellucidum and was totally removed via an interhemispheric anterior transcallosal approach. Histological examination found typical subependymoma, with little vascularity. Intraventricular hemorrhage from cerebral neoplasms is usually due to highly vascular tumors. Since subependymomas are quite benign and show poor vascularity, intraventricular or subarachnoid hemorrhages are very rare, but do occasionally occur.

Comparison of large intrasylvian and subpial hematomas caused by rupture of middle cerebral artery aneurysm.

The clinical characteristics of intrasylvian and subpial hematomas caused by rupture of middle cerebral artery (MCA) aneurysm were examined in 86 patients admitted to our department with subarachnoid hemorrhage (SAH) caused by ruptured MCA aneurysms. A retrospective study of 26 patients with a large hematoma associated with SAH treated surgically within 48 hours evaluated clinical grade at admission, secondary development of cerebral swelling, ratio of hematoma removal, and incidence of symptomatic vasospasm. Clinical grade on admission, age, and sex showed no significant differences. Ratio of cerebral swelling against the initial hematoma volume (p = 0.005), and incidence of symptomatic vasospasm (p = 0.041) were significantly lower, and the ratio of hematoma was significantly higher (p = 0.01) in the subpial hematoma group. Removal of hematoma was more difficult and symptomatic vasospasm was more frequent in the intrasylvian hematoma group. The clinical features of subpial and intrasylvian hematomas caused by rupture of MCA aneurysm should be considered for the better management of associated SAH.

[Intraoperative neuronavigation system without rigid pin fixation].

OBJECT: Integration of neuronavigation into brain tumor surgery can improve the accuracy and precision of resection, but most neuronavigation systems require rigid pin fixation of the patient's head throughout the operation. We describe use of a noninvasive skull reference tool, which can replace rigid pin fixation in awake craniotomy and pediatric surgery, when standard pin fixation cannot be used. METHODS AND RESULTS: The skull reference tool (BrainLAB, Munich, Germany) is directly attached to the outer skull with a small self-tapping screw. Virtual scanning of the surface of the face and head achieves patient registration in seconds without requiring the use of fiducial markers or head fixation. This procedure improves patient comfort, cooperativeness, and compliance, resulting in better operating procedures. This skull reference tool is available for children younger than 3 years of age, in whom pin fixing is dangerous. Twelve patients underwent awake surgery and four pediatric patients younger than 3 years old underwent five procedures using this skull reference tool in our hospital between January 2005 and December 2008. The method of utilizing this skull reference tool was easy and sufficiently accurate in these patients. CONCLUSION: The use of this skull reference tool provides an accurate and comfortable method of frameless navigation in patients undergoing awake craniotomy and pediatric patients.

Evolution of vestibular schwannoma after removal of epidermoid cyst of the same location: case report.

A 71-year-old man presented with vestibular schwannoma manifesting as hearing disturbance and truncal ataxia 16 years after removal of a cerebellopontine angle (CPA) epidermoid cyst, and located adjacent to the remnant lesion. The patient first presented with a 6-month history of right trigeminal neuralgia. Neuroimaging demonstrated a right CPA lesion, suggestive of an epidermoid cyst. Right lateral suboccipital craniotomy was performed and the histological diagnosis was epidermoid cyst. A small lesion remained, but the symptoms were relieved. Sixteen years later, the patient presented with right auditory disturbance, vertigo, and truncal ataxia. Magnetic resonance imaging revealed a multiple cystic mass adjacent to the remnant epidermoid cyst in the right CPA. The lesion was removed and the histological diagnosis was vestibular schwannoma associated with the epidermoid cyst. The irritative effect of the remnant epidermoid cyst or surgical procedures may have caused the vestibular schwannoma, but no evidence of the evolution of the different types of tumors was found.

Adult traumatic leptomeningeal cyst: case report.

A 60-year-old man presented with a traumatic leptomeningeal cyst manifesting as local tenderness in the right parietal region and local headache 2 years after head injury. Magnetic resonance imaging showed a small arachnoid cyst under bone defect. Dural and bone plasty were performed. Intraoperative examination found small and round defects of the dura and bone. Progressive headache was relieved after the surgery. This rare case of adult posttraumatic leptomeningeal cyst occurred within an unusually short period after trauma, and was associated with a small and round bone defect and small dural defect usually characteristic of congenital arachnoid cyst.

Ruptured pseudoaneurysm following Gamma Knife surgery for a vestibular schwannoma.

A 75-year-old woman underwent Gamma Knife surgery (GKS) for a vestibular schwannoma. Eight years after GKS, she suffered sudden onset of headache. Computed tomography revealed diffuse subarachnoid hemorrhage around the cisterns of the posterior fossa. Right vertebral artery angiography showed an aneurysm arising from the lateral pontomedullary segment of the left anterior inferior cerebellar artery. The aneurysm was not located at a branching site. Trapping of the distal anterior inferior cerebellar artery aneurysm was performed, and the aneurysm was removed. The pathological features of this aneurysm are discussed. This aneurysm was diagnosed as a pseudoaneurysm pathologically. This is the first report of aneurysm formation with pathological findings following GKS for a vestibular schwannoma.

A case of multiple pial arteriovenous fistulas associated with dural arteriovenous fistula.

Pial arteriovenous fistulas (AVFs) are known as rare cerebrovascular lesions. They are composed of >/= 1 arterial feeding vessels and a single draining vein that usually has high perfusion pressure and generally occur in infants. Cases involving adults are very rare and the developmental mechanisms and natural history of these lesions remain unknown. The authors present a case of multiple pial AVFs in an adult in whom the lesions developed after radiosurgical treatment of dural AVFs. Direct disconnection of pial arterial supplies was performed, and the abnormal shunts were successfully eliminated. The authors report the clinical course of this case and discuss the characteristics of and treatment strategy for multiple pial AVFs, reviewing the published literature.