Primary central nervous system (CNS) lymphoma is no longer not a rare tumor in even immunocompetent hosts. Radiotherapy can achieve high response rates in most patients with CNS lymphoma, but the survival is usually only 12-18 months because the tumor recurs. In this study the addition of intravenous high-dose methotrexate (HDMTX) prior to irradiation markedly improved the time of both tumor-free and overall survival. Other chemotherapeutic agents such as CHOP (cyclophosphamide, doxorubicin, oncovin, prednisone) and nitoroureas were ineffective. Rapid infusion of HDMTX (rapid HDMTX) resulted in more enhanced penetration into cerebrospinal fluid and reduced the tumor volume much more significantly than regular infusion of the drug (regular HDMTX). The rapid HDMTX yielded a median survival of at least 60 months and 5 year survival rates of 62%. There was no difference in acute side effects including bone marrow suppression between rapid HDMTX and regular HDMTX. Late neurotoxicity such as progressive dementia occurred in 15-16% of patients in both treatment groups. High-does chemotherapy of rapid intravenous infusion of MTX is very effective in the treatment of CNS lymphomas, but the issues of neurotoxicity, drug-resistance and possible combination drugs need to be addressed in future.

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The frontal lobe contains the precentral gyrus as well as the superior, middle and inferior frontal gyri. The opercular and triangular portions of the inferior frontal lobe can be identified by the ascending and horizontal branches of the sylvian fissure. By understanding this surface anatomy, the following language function related areas can be identified : the posterior part of the inferior frontal gyrus (Broca's area), the posterior part of the middle frontal gyrus (Exner's writing area) and the inferior portion of the precentral gyrus (motor cortex). Injury to any of those areas may cause language related symptoms. It is important to evaluate functional localization when ever surgery is planned around those areas. Localization of the language function may vary between individual patients. It is also important to know that lesions strictly restricted to Broca's area rarely cause typical symptoms of Broca's aphasia.

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Epilepsy surgery is basically composed of two methods, resection and disconnection. Disconnection surgery involves corpus callosotomy, multiple subpial transection (MST), and hemispherotomy (modified functionalhemispherectomy). Corpus callosotomy is very effective for drop attacks which often accompany bilateral synchronous spike and waves on EEG. Although improvement of cognition is frequently observed after surgery in children, disturbance of psychosocial adjustment is not rare in adult. MST was originally developed for the treatment of epileptic foci in unresectable cortical areas. This technique is also instrumental in treating disseminated extensive epileptic foci. During surgery, repeated electrocorticography is essential to obtain satisfactory surgical results. Postoperative neurological deficits are rarely encountered after this procedure.

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Assessment of language lateralization is crucial in patients considered for neurological surgery. The authors used functional MRI (fMRI) in conjunction with shiritori, a kind of word-generation task as paradigms, to determine language lateralization in the patients. We used a 1.5 Tesla magnetic resonance imaging devise with an echoplanar imaging sequence. Thirty-two patients undergoing neurological surgery would alternately rest and silently perform shiritori during fMRI acquisition. Language lateralization was determined in 29 out of 32 patients. Twenty-two patients were considered as left-hemisphere dominant and seven were right-hemisphere dominant. Brain activation was seen in the prefrontal area, premotor area, superior temporal gyrus and parietal lobe of the dominant hemisphere, which is consistent with the results in normal adults. Language lateralization was particularly useful in a case of meningioma in the left lateral ventricle and in a case of AVM in the left temporoparietal region. fMRI with shiritori tasks revealed right-hemisphere dominance in both cases, which was also confirmed by intracarotid amobarbital (Wada) testing. Both lesions were treated successfully without causing any further deficit to the patients' a language function. These result suggest that fMRI with shiritori tasks can be used to assess language lateralization non-invasively, compared with the current techniques, such as intracarotid amobarbital testing and cortical electrostimulation mapping. Thus, fMRI with shiritori tasks has significant clinical potential as a presurgical evaluation tool.

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We explained the pitfalls associated with microvascular decompression surgery (MVD) for hemifacial spasm and comment on their overcome, based on our surgical experience and studies of the microsurgical anatomy. Especially we referred to : especially (1)factors causing difficulty in observation of the exit zone of the facial nerve, (2)factors causing postoperative hearing disturbance, (3)factors causing postoperative hemifacial paresis, and (4)factors causing insufficient improvement of the hemifacial spasm. In the statement were also presented the procedures of the infrafloccular approach, which is the best approach to expose the exit zone of the facial nerve. This approach requires the following techniques : the bony opening to obtain the direction of the sight under the microscope, dissection between the flocculus and the 9th cranial nerve, and the rostral retraction of the flocculus. We discussed factors influencing surgical results focusing on both the patient's anatomical conditions and the surgeon's knowledge and experience. To obtain good surgical effects and reduce complications, surgeons attempting to perform this MVD should study the microsurgical anatomy of the structures surrounding the facial nerve and the infrafloccular approach technique.

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We report a case of intracerebral pneumatocele following a traumatic head injury in addition to a review of pneumocephalus from the cases past 20 years. A 40-year-old male was admitted to hospital because of a strong blow to his forehead received in a vehicle accident. A CT scan performed on admission showed a cerebral contusion in both frontal lobes accompanied by a skull base fracture. However, intracerebral pneumocephalus was not detected. About 1 month after the accident, CSF rhinorrehea was noted, but could not be halted by lumbar drainage. Forty-five days after the accident, MRI showed intracerebral pneumocephalus in his right frontal lobe. Seventy-four days after the accident, surgery for repairing the skull base fracture was performed. During the surgery, it was noted that some parts of the right frontal contusion were adhered to the edge of the lacerated dura around the bone defect of the frontal sinus. The air cavity of the frontal lobe communicated with the frontal sinus. After dissecting and cutting off the herniated brain, the air cavity of the frontal lobe shrunk. Continuous inflammation, such as meningitis, may cause the partial destruction of the herniated cortex, and provide a trajectory for intracerebral pneumocephalus from the paranasal sinus into the cortex. As for the cause of the delayed CSF rhinorrehea, we thought it oozed from the lateral ventricle through the intracerebral pneumocephalus, or from the subarachnoid space at the frontal lobe.

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A case is reported of a 48-year-old woman with a spinal subdural hematoma presented with severe back pain and sharp generalized headache. On admission, the patient presented with hypalgesia on her left leg but no motor weakness. Magnetic resonance (MR) images performed 5 days after addmission, revealed a subdural mass extending anteriorly from Th10 to S1 level that was diffusely bright on T1- and T2-weighted images. These studies revealed an acute spinal subdural hematoma associated with spinal subrachnoid hemorrhage. Because the patient retained normal lower extremities function, it was decided not to evacuate the hematoma but to choose conservative management. Her clinical symptoms disappeared about 14 days after onset and spinal compression cleared in 1 month. However the patient was readmitted 3 months later and revealed paraparesis. MR images revealed a mass between the levels of Th6 to Th9 depicted as a low intensity signal on T1-weighted images and a high intensity signal on T2-weighted images. We diagnosed spinal arachnoid cyst induced by the spinal arachnoiditis following subdural hemorrhage associated with spinal subarachnoid hemorrhage. Subtotal cyst removal was insufficient, resulting in necessity of shunting of the cyst into the peritoneal cavity. Spontaneous acute spinal subdural hematoma is a rare spinal disease. Most of patients have been treated with surgical procedure, but in a few patients in whom neurological impairment is minimal, have been reported in which hematoma resolved spontaneously with conservative management. However, the careful observation may be needed using MR imaging if the subdural hematoma associated with spinal subarachnoid hemorrhage is expanded and large.

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We report a rare case of thalamic glioma developing extensive dissemination following a stereotaxic needle biopsy. An 18-year-old female underwent stereotaxic needle biopsy for a right thalamic tumor in May 1999. Histological examination revealed glioblastoma multiforme. Local radiation limited to the thalamic region along with an adjuvant chemotherapy was administered, to which the tumor responded completely on imaging studies. Five months later, however, extensive dissemination into the cerebrospinal fluid (CSF) space developed, with a mass lesion formed at the biopsy tract in the right frontal lobe which required a craniotomy to be resected. Although tumor dissemination into the CSF space is a rare event following a needle biopsy, careful monitoring by imaging studies is necessary not to delay diagnosis of this rare complication.

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