Search

Considering that most meningiomas are pathologically benign, tumors located in the cerebellopontine angle and petroclival area should be reduced as much as possible, and radiation therapy should be administered if necessary. Consequently, relatively good preservation of cranial nerve function and local lesion control can be expected. However, because the lesions are generally located deep, and are surrounded by various important structures, performing surgical procedures is difficult, and careful management of the surgical strategy is important to avoid complications. Surgical outcomes have dramatically improved with the development of skull base and microsurgical techniques. The main surgical approaches for cerebellopontine angle meningiomas and petroclival meningiomas currently include the anterior and posterior combined transpetrosal, anterior transpetrosal, and lateral suboccipital approaches. Furthermore, with the recent developments in endoscopic surgery, minimally invasive surgery for skull base meningiomas has gradually been introduced. In this article, we explain the preoperative checkpoints, selection of the surgical approach, and surgical techniques for the resection of cerebellopontine angle meningiomas and petroclival meningiomas.

Patients with parasellar meningiomas often initially present with visual impairment. Understanding the surrounding anatomy is essential when preparing for surgery of parasellar meningiomas, as this region includes various crucial neurovascular structures. Historically, invasive craniotomy, such as the orthozygomatic approach or zygotomy, has often been attempted to access the region; however, the use of these invasive approaches has become less common, because of the accumulation of anatomical knowledge, as well as the development of surgical techniques and devices, including the endonasal endoscopic approach. Herein, we summarize how we perform surgery for parasellar meningiomas, and outline tips and pitfalls that could be useful for young residents and trainees who are new to the skull base field.

The debate regarding the role and clinical impact of radiotherapy for meningiomas remains underdeveloped due to insufficient evidence. However, following recent revisions in the WHO classification and the integration of molecular diagnostics, there has been a substantial shift in the stratification of recurrence risks. Nevertheless, the specific circumstances under which radiotherapy proves crucial remain unclear. As risk stratification becomes more refined, the effectiveness of radiotherapy in treating high-risk meningiomas continues to be a contentious issue. Concurrently, there is vigorous discussion regarding the management of 'brain invasion in otherwise benign'(BIOB)meningiomas. The incorporation of PET imaging alongside MRI for defining radiation targets is increasingly acknowledged as advantageous. Boron neutron capture therapy(BNCT), which specifically targets the biological characteristics of tumor cells in invasive regions, is also gaining significant traction as a promising therapeutic approach for meningiomas with infiltrative components.

During surgery for meningioma, basic surgical techniques and strategies required for the removal of the tumor are common, particularly for tumors located superficially, such as convexity, parasagittal, and falx meningiomas. Four basic surgical techniques, including detachment; devascularization; debulking; and dissection should be combined and repeated in appropriate sequence, tailored to the specific conditions of each tumor. This eventually enables the total circumferential dissection of the tumor from the surrounding tissues. It is essential to retract the tumor towards the space created at the tumor center through internal debulking, rather than retracting the normal brain, to avoid damage to the surrounding brain tissue. During surgery for parasagittal meningioma with venous sinus occlusion, it is crucial to preserve the cortical veins that have developed as collateral pathways to prevent venous complications. During surgery for falx meningioma, the selection of a surgical approach including a contralateral approach based on factors such as the development of bridging veins and significant peritumoral brain edema is required. In this article, detailed surgical procedures for convexity meningioma, parasagittal meningioma, and falx meningioma were described focusing on the application of fundamental surgical techniques tailored to each tumor type.

The jugular foramen, also known as the foramen magnum, is a highly intricate region of the skull base through which numerous critical blood vessels and nerves traverse. Meningiomas, the most common tumors in neurosurgical pathology, can arise at any location where the meninges are present, posing significant challenges. Meningiomas involving the jugular foramen and sublingual neural tube are particularly notable for their potential to extend from intracranial to extracranial sites, necessitating familiarity with extracranial anatomy, which is not typically encountered in clinical practice. A comprehensive understanding of anatomical characteristics, along with an ample field of view and working space, is crucial for handling the cerebellum, brainstem, and nerves meticulously. The use of surgical support tools such as neuromonitoring and navigation is essential for enhancing the safety of the procedure. Furthermore, preparedness for treatment options, rehabilitation, and adjunctive therapies is vital in the event of neurological symptoms such as those affecting the glossopharyngeal, vagal, or hypoglossal nerves.

Preoperative embolization(POE)of intracranial meningioma is performed worldwide. Although clear evidence of the effectiveness of POE has not been reported in the literature, the technique plays an important role in open surgery, especially for large or skull base meningiomas. The purposes of embolization include: 1)induction of tumor necrosis, resulting in a safer operation, 2)reduction in intraoperative bleeding, and 3)decrease in operative time. Knowledge of the functional vascular anatomy, embolic materials, and endovascular techniques is paramount to ensure safe embolization. Our standard procedure is as follows: 1)embolization is performed several days before open surgery; 2)in cases with strong peritumoral edema, steroid administration or embolization may be performed immediately prior to surgery; 3)patients undergo the procedure under local anesthesia; 4)the microcatheter is inserted as close as possible to the tumor; 5)particulate emboli are the first-line material; 6)embolization is occasionally performed with N-butyl cyanoacrylate(NBCA)glue; and 7)if possible, additional proximal feeder occlusion with coils is performed. The JR-NET study previous showed the situation regarding intracranial tumor embolization in Japan. Endovascular neurosurgeons should fully discuss the indications and strategies for POE with tumor neurosurgeons to ensure safe and effective procedures.

Meningiomas are the most common brain tumors, often in the form of extra-axial masses adhering to the dura mater. Although there are typical imaging findings, meningiomas have a wide variety of imaging findings, owing to their different histological subtypes. Thus, it can be difficult to differentiate meningiomas from other diseases that present with similar imaging findings. This section outlines mimickers for monitoring meningiomas that present with imaging findings similar to those of meningiomas. Diseases that form masses and require differentiation from meningiomas include schwannomas, solitary fibrous tumors, dural metastases, and histiocytosis. Diseases that primarily present as dural thickening and require differentiation from meningiomas include hypertrophic duralitis, fungal infections, and IG4-related diseases. Notably, in addition to the various pathologies that can mimic meningiomas, such as those listed above, there are also cases in which the diagnosis of meningioma is difficult because of additional modifications, such as metastasis or meningioma infarction.

Recent advancements in endoscopic transnasal surgery(ETS)have expanded the application of this technique to meningiomas in the central skull base area, offering a less invasive alternative with a potentially lower physical burden on patients than conventional microscopic skull base surgery. Notably, while ETS allows surgeons to reach tumors without traversing the brain and nerves, thus theoretically reducing the risk of cranial nerve damage, it requires a high level of proficiency to avoid inadequate resection and tumor recurrence. In this article, we discuss the various surgical considerations, including preoperative imaging, surgical setting, nasal cavity expansion, skull base opening, tumor removal, and skull base reconstruction, as general procedures for specific meningiomas. We further describe the concept and details of our multi-layer fascial closure technique for dural repair in ETS, underlining the importance of skilled dural reconstruction in preventing postoperative complications. In conclusion, while ETS for skull base meningiomas presents a promising and less invasive treatment option, its success relies heavily on the surgeon's experience and understanding of the skull base anatomy, stressing the need for careful approach selection.

Meningiomas are the most common primary intracranial tumors. As the number of incidentally discovered meningiomas has increased with the widespread access and use of neuroimaging, treatment strategies for meningiomas have become more important. Close observation is the first choice for asymptomatic lesions; however, the natural history of meningiomas remains unclear. It is necessary to recognize the characteristics of meningiomas that are likely to grow, such as high signal intensity on MRI T2WI. It is also important to examine the growth rates and patterns using multiple neuroimaging examinations during the follow-up period. The authors suggested a relationship between the various observed growth patterns and the length of the follow-up period based on the assumed development of tumor volume. Less than 10% of patients with asymptomatic meningiomas develop symptoms and require treatment. However, it remains unclear which lesions become symptomatic, and further studies are required. Lesions with a sustained growth pattern undergo preventive treatment interventions, but the need for and appropriate timing of these interventions are continuously under debate. Further studies will help elucidate the natural history of meningiomas.

The frequency of identification of asymptomatic meningiomas is increasing owing to the advancement and widespread use of CT and MRI. The first choice for asymptomatic meningiomas is observation. Approximately 70% of asymptomatic meningiomas increase in volume on long term follow-up. More than half of them reportedly exhibit a self-limiting pattern, in which growth eventually stops. Imaging findings related to increased meningioma volume include no calcification, large tumor size, high signal intensity inside the tumor on T2-weighted images, high brightness within the tumor on diffusion-weighted images, and perifocal edema. We also highlighted the presence of hypo-intensity of the surface layer on T2-weighted imaging, indicating growth arrest in a self-limiting growth pattern of meningioma. In this article, literature reports on image prediction using CT and MRI regarding the growth of asymptomatic meningiomas were reviewed, along with our report.

The basics of meningioma surgery are represented in the '4Ds': Detachment, Devascularization, Debulking, and Dissection. When considering the 4Ds, surgical simulation using 3D images is useful, as it allows the surgeon to understand the 3D relationship between the tumor, feeding vessels, and surrounding tissues. However, the hardness of the tumor and the degree of adhesion between the tumor and surrounding tissue are difficult to determine based on 3D images, and must therefore be confirmed using MRI, such as T2-weighted images.

Preoperative simulation for endoscopic endonasal approach(EEA)using computed tomography and magnetic resonance imaging evaluates tumor extension and the relationship between adjacent structure(the pituitary stalk, major vessels, and cranial nerves); therefore, preoperative planning of nasal procedure, skull base bony removal, and cranial base reconstruction are possible. Additionally, three-dimensional(3D)fusion image aids surgeons to visualize intraoperative 3D findings. These preoperative simulations are critical to avoid complications and predict pitfalls perioperatively. However, tumor consistency or adhesion with adjacent structure cannot be predicted but is judged perioperatively, which affects the extent of tumor resection. This manuscript describes important points of preoperative simulation for EEA, especially the transplanum-transtuberculum approach for craniopharyngiomas or tuberculum sellae meningiomas, showing some examples in patients.

DuraGen ® , an absorbable, engineered collagen-based artificial graft was introduced in Japan in September 2019 for cranial, transsphenoidal, and spinal surgeries. In addition to its efficacy and safety profile, owing to sutureless dural repair, DuraGen ® is widely accepted by neurosurgeons. Direct tenting with DuraGen ® is occasionally required in patients with large dural defects, particularly in cases of tumors adherent to the dura. To overcome this limitation, we introduced a surgical technique for epidural tenting using DuraGen ® . A 78-year-old man with a history of alexia underwent craniotomy for resection of a left temporal lobe metastatic tumor. We completely removed the recurrent tumor, which was strongly adherent to the dura in the middle cranial fossa. A layer of DuraGen ® was used as a subdural underlay beneath the autologous dura to close the wide dural defect. To avoid postoperative epidural fluid collection, we retracted the DuraGen ® from the epidural aspect and interposed several pieces of muscle, which were sutured on the subdural aspect to ensure that the muscle pieces securely plugged the dural defect. We placed an additional overlay of DuraGen ® along the autologous dura. The patient's postoperative course was uneventful without cerebrospinal fluid leakage, tension pneumocephalus, or wound infection. Reoperations for tumor resection, particularly surgical procedures for refractory meningiomas and malignant tumors cause increasing fragility and wide defects of the dura. DuraGen ® placement enables sutureless closure and is less time-consuming. Our technique of epidural direct tenting with DuraGen ® using muscle pieces sutured on the subdural aspect could be useful in patients with significantly large dural defects and can prevent postoperative epidural fluid collection to ensure complete dural sealing.

Meningioma and glioma represent two common primary intracranial tumors. However, the coexistence of these two lesions in the same patient at the same location is rare. Here, we present a case of a fibroblastic meningioma with a secondary glioblastoma occurring at the same location. A 67-year-old woman underwent surgery for a left frontal parasagittal meningioma, and the tumor was subtotally removed. Two years and 11 months after the surgery, the patient had a tumor at the same location with invasion into the adjacent brain, suggesting recurrent meningioma with malignant transformation. The resected tumor was confirmed histopathologically as a glioblastoma. Genetic analysis revealed that the isocitrate dehydrogenase 1 and 2 genes were wild type, and the TERT promoter mutation was detected. The gene analysis suggests that the tumor was a de novo glioblastoma, not a secondary glioblastoma from a lower-grade glioma. (Received April 9, 2020; Accepted May 27, 2020; Published October 1, 2020).

A 36-year-old woman presented with temporal visual field defect in the 27th week of her pregnancy. Magnetic resonance(MR)imaging demonstrated a tuberculum sellae meningioma compressing the optic chiasm. Although we planned surgical resection after her delivery, the symptom worsened in the late stage of her pregnancy. After administering a steroid medication, the symptom stabilized. In the 38th week of pregnancy, she delivered a child, and interestingly, her visual field defect improved, and MR imaging demonstrated tumor shrinkage. However, at the request of the patient, we performed the tumor resection by extended endonasal transsphenoidal surgery. The histological diagnosis was angiomatous meningioma, and the tumor cells were strongly positive for progesterone receptors. This is a very rare case of tuberculum meningioma wherein the patient showed a natural improvement in visual function after delivery. Regarding the appropriate surgical timing for meningioma, spontaneous shrinkage of meningioma after delivery would be considered an option.

Objectives: Primary meningiomas arising outside the intracranial component are rather rare and have been termed primary extradural meningiomas(PEMs). We present a case of an intraosseous-type PEM occurring at a high convexity location and discuss the clinical characteristics of PEMs., Case: An 80-year-old woman presented with a soft and painless subcutaneous mass of approximately 10 cm in diameter in the right parietal region, which had appeared 1 year previously. Mild cognitive dysfunction and left hemiparesis were observed upon admission. A skull radiograph and a bone window computed tomography scan revealed an osteolytic lesion at the above-mentioned site. Magnetic resonance imaging indicated that the mass was inhomogeneously enhanced and seemed to extend through the skull defect both intra- and extra-cranially. The preoperative diagnosis was a metastatic skull bone tumor due to the patient's history of breast cancer. During surgery, the tumor was found to be solid and had expanded through both the inner and outer tables of the skull, destroyed the inner table at one location, and perforated into the subdural space via the thinned, but not infiltrated, dura mater. The tumor was removed along with a wide margin of surrounding healthy bone and a cranioplasty was performed using a titanium plate. The histopathological diagnosis was atypical meningioma(World Health Organization grade II). Postoperatively, no adjuvant therapies(radiation and/or chemotherapy)were administered and the patient was reported to be well at 8 months post-surgery with no evidence of tumor recurrence., Conclusions: Although PEMs are rather rare, clinicians should consider the differential diagnosis of osteolytic skull vault tumors.

We present a rare case of supratentorial meningeal melanoma associated with ipsilateral nevus of Ota, and a review of the literature. The patient was a 32-year-old man with a right-sided nevus of Ota, presenting with unconsciousness. His CT and MRI scans revealed an extra axial tumor with dural tail signs; no lesion was detected on systemic examination. Intraoperatively, the tumor demonstrated black hyperpigmentation and was histologically diagnosed as malignant melanoma. Following surgery, he received radiotherapy and chemotherapy. For over a year and a half, the patient has shown no recurrence of the lesion.

A 68-year-old man presented with abnormal behavior and Todd's paralysis on the right side after having taken a bath. Computed tomography and magnetic resonance imaging revealed a tumor mimicking convexity meningioma that had a perifocal edema, although its mass was not very large. The patient underwent surgery, and full recovery was achieved following a total removal of the lesion. Pathohistological examination demonstrated an intermediate type of Castleman's disease. The final diagnosis was intracranial localized Castleman's disease because the results of the full physical examination and laboratory analyses were normal. Castleman's disease is a rare lymphoproliferative disorder of unknown etiology. Moreover, intracranial involvement is very rare. In cases of intracranial meningeal tumors with perifocal edema, we should take this disease into consideration in the differential diagnosis.

Purpose: Small meningiomas causing hydrocephalus without obstruction of the ventricular system are rare. Herein, we report a case of small clinoidal meningioma with communicating hydrocephalus, which resolved after tumor removal., Case Presentation: A 70-year-old woman presented with a 1-month history of memory disturbance followed by gait disturbance. MR images revealed a right clinoidal meningioma, 2 cm in diameter, and dilatation of the ventricles suggesting communicating hydrocephalus. The cerebrospinal fluid(CSF)pressure was 130 mmH 2 O, as determined via a lumbar puncture. High concentrations of protein(65mg/dL)were detected in the lumbar CSF. The tumor was completely removed via a frontotemporal craniotomy. Higher protein concentrations(94mg/dL)were detected in the CSF obtained intraoperatively from the sylvian cistern. The histopathological diagnosis was meningothelial meningioma. The patient's symptoms improved markedly after surgery. Postoperative MR images revealed resolution of the hydrocephalus. The lumbar CSF protein concentration returned to normal(43mg/dL). Neither tumor recurrence nor progression of hydrocephalus has been observed for 4 years., Discussion: Communicating hydrocephalus, associated with a small meningioma at the supratentorial region, has not been described. Previous studies have shown that patients with meningioma may develop communicating hydrocephalus after tumor removal or stereotactic radiosurgery. Thus, it is interesting that the small supratentorial meningioma in our case developed communicating hydrocephalus without any therapeutic intervention. Considering the CSF protein concentration, we speculate that the hydrocephalus was the result of CSF malabsorption associated with high CSF protein concentration and CSF pathway obstruction at the suprasellar cistern caused by the tumor.

Embosphere ® was approved in Japan for embolizing intracranial arteries for the reduction of intraoperative bleeding in January 2014. Until August 2015, we performed embolization for four meningiomas using Embosphere ® . We performed an initial evaluation of all the cases, including evaluation of the clinical courses, change in the maximum tumor diameters and volumes, alteration in the appearance on magnetic resonance imaging(MRI), amount of intraoperative bleeding, complications, and histopathological findings. After embolization, the maximum tumor diameters and volumes slightly decreased on MRI, whereas the signal change on diffusion-weighted imaging(DWI)or fluid-attenuated inversion recovery(FLAIR)varied in each case. One case demonstrated a partial signal change on DWI one day after the initial procedure, and another case demonstrated a decrease in perifocal edema on FLAIR. Among our patients, least bleeding was recorded at 6 days after the embolization. Histopathological analysis revealed coagulative necrotic lesions in two cases. The von Kossa stain was used to distinguish Embosphere ® from the psammoma body. One case involved a thromboembolic complication of the retinocentral artery caused by an Embosphere ® of 100-300 μm. Our early-stage experience suggests that an Embosphere ® of 300-500 μm should be used for safe embolization before resection to avoid thromboembolic complications because an Embosphere ® of 100-300 μm can pass through the dangerous anastomosis. Our present strategy was to resect the tumor approximately seven days after the embolization using Embosphere ® . However, further studies and discussion on the size of Embosphere ® , and the interval between pre-operative embolization and surgical removal are needed.

Background: In the surgeries of the upper part of the cerebellopontine angle (CPA), the petrosal vein (PV) is an obstacle, and the resection of the PV sometimes causes postoperative complications such as cerebellar hemorrhagic infarction. On the other hand, it can be an anatomical landmark during the surgery. We have used three-dimensional (3D) CT images for preoperative evaluation. We, herein, report 4 cases of CPA lesions., Method: The PV was imaged with neighboring structures using CT and a workstation. We paid attention especially to the vein of the cerebellopontine fissure (VCPF)., Result: The four cases include one case of trigeminal neuralgia, two meningiomas and one case of acoustic schwannoma. 3D CT images showed (1) the anatomical formation such as course of the PV, (2) relationship to the neighboring structures of the tumors, (3) expectation of complications after sacrificing the PV. By observing the preoperative 3D CT images, we were able to plan safety operative approaches and procedures., Conclusion: 3D CT images of the PV are very useful for preoperative evaluation of surgery in CPA lesions.

We report the case of a 34-year-old woman who exhibited acute deterioration in her condition after cerebral angiography for evaluation of a large meningioma. She had undergone surgery and irradiation for a glioma in the right occipital lobe 23 years before this episode. She experienced incapacity at work. On CT and MRI, a large meningioma was detected on the left frontal convexity; this tumor was thought to be radiation-induced. Cerebral angiography was performed to assess the vascularization of the tumor. Her condition began to deteriorate 2.5 h after the cerebral angiography. CT revealed an increase in the mass of the tumor, and a high density area in the tumor. We immediately removed the tumor. Histopathological examination revealed the tumor to be a meningothelial meningioma. New hemorrhagic foci were identified in the tumor. In addition, macrophages containing hemosiderin were detected, and some of the tumor vessels exhibited hyaline degeneration. We suspected that angiography triggered bleeding in the meningioma, which was already predisposed to hemorrhage.

We have had more opportunities to treat incidental meningiomas owing to the recent development of neuroradiological imaging. Generally, most of them are treated conservatively unless they grow rapidly or change to symptomatic. Rapidly growing meningiomas are unusual because meningiomas are generally benign and slow-growing tumors. Particularly, the indication of surgery in elderly patients with asymptomatic meningiomas must be considered very carefully because of the higher risks of complications or postoperative neurological deficits. The author describes a rare case of a rapidly growing dumbbell-shaped convexity meningioma in an elderly patient. The tumor was removed completely (Simpson grade II), and the pathological diagnosis was atypical meningioma. There was a difference of MIB-1 LI within the tumor, which suggests that the difference of proliferation within the meningioma may have changed it into "dumbbell-shaped". The only factor we could identify to explain the rapid growth was the high MIB-1LI. This represents an interesting example of a rapidly growing meningiomas. Although the indication of aggresive surgery in elderly patients with symptomatic meningiomas should be considered, the postoperative deterioration of quality of life must be avoided. And earlier postoperative rehabilitation can be regarded as indispensable for elderly patients.

We present a case of a 55-year-old woman with intracranial lipomatous meningioma attached to the left sphenoid ridge. A CT showed a mass lesion partially with a hypodensity area in the left fronto-temporal lobe. On MRI, the mass lesion contained a hyperintensity portion on T1 weighted images, which changed to hypointensity on fat-suppressed-T1 images. Histological examinations demonstrated a transitional meningioma containing lipomatous portions. Immunohistochemical studies showed negative reactivity for epithelial membrane antigen (EMA) and positive reactivity for vimentin and S-100 in the areas with lipomaous foci. This pattern of reactivity was different from that of lipomatous meningiomas reported previously. Further examinations are needed concerning the origin of tumor cells in lipomatous meningiomas.

We report a case of foramen magnum meningioma in which case enhanced three-dimensional CT scan was valuable for preoperative evaluation of the surgical approach. A 53-year-old woman had suffered from stiffness and pain in the left occipital region and numbness of the left side of the face for about 2 years before admission. She had also weakness and numbness of the left side of her body for about 2 months before admission, and dysphagia and pain in the occipital region and in the posterior region of the neck produced by straining for about 1 month before admission. Neurological examination revealed left hemiparesis, and hypalgesia and tactile hypesthesia of the left side of the body, including the face. Plain X-P was normal. Enhanced CT scan and gadolinium enhanced MRI revealed a well-enhanced mass attached to the left anterolateral part of the foramen magnum. The left occipital condyle was observed at the lateral side of the attachment part of this mass. Angiography revealed tumor feeders from the meningeal branches of the left vertebral artery and the left ascending pharyngeal artery. Enhanced three-dimensional CT scan clearly showed that the tumor was attached to the left anterolateral part of the foramen magnum, that the left occipital condyle was at the lateral side of the attachment part of this mass and that the jugular foramen and jugular tubercle were situated superolateral to the attachment part of this mass. Considering these factors, we decided that removal of the posterior part of the left occipital condyle was necessary, but removal of the left jugular tubercle was not necessary for a good operative view from the left posterior lateral direction. The tumor was totally removed successfully and good results were obtained by the transcondylar approach without removal of the jugular tubercle. Histology of the tumor revealed meningothelial meningioma. In this case, preoperative evaluation with enhanced three-dimensional CT scan was helpful for deciding the surgical approach. With enhanced three-dimensional CT scan, it is easy to judge whether removal of the posterior part of the occipital condyle and/or the jugular tubercle is necessary for a good operative view, and we can get good images revealing the relationships between the tumor and surrounding structures. Preoperative evaluation with enhanced three-dimensional CT scan is very useful especially in this kind of situation.

We repeatedly measured kinetic rate constants and glucose metabolic rate (kinetic rCMRG1) using dynamic positron emission tomography (PET) and autoradiographic rCMRG1 in a patient with recurrent meningioma. A 50-year-old woman who presented with a left visual disturbance was admitted to our hospital. MR images revealed a mass lesion occupying the left middle fossa. The patient underwent Simpson grade IV surgery. The histological diagnosis was meningothelial meningioma. One year later the tumor had grown back to almost the same size as before treatment and was removed again by Simpson grade IV procedure. Postoperatively, the patient underwent radiation therapy (54 Gy). Two years after the second operation, the tumor was found to have invaded the left orbit and was resected by Simpson grade IV procedure. After additional radiation therapy, the patient was discharged. The rate constants were analyzed preoperatively and whenever the tumor recurred according to the three compartment 18F-fluorodeoxyglucose (FDG) model. Preoperative PET indicated tumor k1 and k2 values higher than in the contralateral gray matter, suggesting high permeability due to absence of the blood-tumor barrier and an abundant blood supply. The tumor k3 value, an indicator of hexokinase activity, was as high as in the contralateral gray matter. When the tumor recurred, the tumor k1, k2 and k3 values remained consistently high, indicating high proliferative activity. In contrast, the contralateral gray matter k1, k2 and k3 values decreased to some extent, suggesting effects of surgery or radiotherapy. Tumor rCMRG1 values, both autoradiographic and kinetic, were enhanced markedly.(ABSTRACT TRUNCATED AT 250 WORDS)

32 cases of traumatic subdural hygroma (TSH) in adults with surgical treatment were retrospectively investigated by means by clinical features and CT findings. The cases consisted of 29 males and 3 females, aged 41 to 87 years (mean 69). Preparative CT scan of all cases revealed low density area and crescent shape in frontotemporal or frontoparietal subdural space. Half of the cases had bilateral lesions. At operation of TSH, color of subdural fluid collections was more water clear or xanthochromic than bloody. As a results, 22 out of 32 cases (69%) in TSH improved with surgical treatment. Many of effective cases of surgical treatment in TSH had short interval from trauma to operation and light disturbance of consciousness before operation. However, the other intracranial damage will also affect the clinical outcome of TSH, because the majority of cases in this study was accompanied by an intracranial damage including cerebral contusion, subarachnoid hemorrhage or intracranial hemorrhage. Nevertheless, surgical management for TSH was so effective that the operation should be undergone sooner interval from trauma, simultaneously considering the another intracranial lesions except TSH. But then, we experienced 7 cases (22%) of ventricular dilatation and 5 cases (16%) of chronic subdural hematoma in postoperative follow up CT scans. In 5 cases among the former, ventriculoperitonial shunt was done, and in 3 cases among the latter, burr hole evacuation was performed. Therefore, the postoperative course of TSH should require careful observation by CT scan and so on.

BALT magic catheter (PURSIL catheter) is a new catheter which is more flexible and plaint than the TRACKER-18 catheter because its mid-section and distal portion are made from polyurethane and silicon rather than polyethylene. Because the PURSIL catheter is flexible, it cannot be inserted with a guide wire, although it can be inserted into circulation during injection of contrast medium. Its inner diameter, 3.5mm, is smaller than that (5mm) of the TRACKER. There are few reports of embolization with the PURSIL catheter, and these describe only embolization using adhesive liquid embolus material. Embolization using small particles through the PURSIL catheter has never been reported. We report the catheterization using the PURSIL catheter of 26 arteries in 15 patients. The catheter was used for superselective angiography to clarify feeder and amytal tests in 5 patients with AVM, and embolization using PVA particles (150-250 microns) was performed in 1 patient with AVM, 3 patients with dural AVM, 4 cases with meningioma and 1 patient with vertebral aneurysm. Small PVA particles were easily injected without resistance through this catheter. In only one patient with dural AVM, was catheterization with this catheter not successful, and that was because the distal portion of the internal maxillar artery was extremely tortuous because of severe atherosclerosis. No complications associated with the use of this catheter were observed. We think that the greatest advantage of this catheter is the safety afforded by not using a guide wire. A disadvantage of this catheter is that, because of its small inner diameter, only small particles, or liquid embolus material can be injected through it.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of intraosseous meningioma at the posterior fossa was reported. Intraosseous meningioma is very rate and only six cases have been reported in Japanese literature. A 64 year-old woman complained of progressive headache and was admitted to Ichinomiya Neurosurgical Hospital. On admission, neurological examination did not reveal any abnormalities. However, plain skull X-p showed a hyperostotic lesion in the right posterior fossa. CT scan demonstrated homogeneously enhanced mass by contrast medium. MRI showed a mass lesion of the posterior fossa on T1 and T2 weighted images. The right vertebral angiogram showed an avascular area in the right posterior fossa and no tumor stain. The tumor, which was partially attached to the underlying dura, was successfully removed surgically. The operative finding confirmed an intraosseous meningioma which had arisen from the right asterion. The post operative course was uneventful. Histological examination revealed fibroblastic meningioma.

Cystic meningioma is rare and said to account for 1 to 2% of all types of meningioma. Here we report two cases of cystic meningioma. Case 1 is a 25-year-old man. He had suffered from sporadic epileptic seizure for about two years until the first CT was performed. It revealed a large cystic lesion at the right parietal region in touch with the midline structure. A nodular high density area was delineated in the contrast enhanced CT on the medial wall of the cyst. He showed no neurological abnormality at all. Case 2 is a 56-year-old female who had been complaining of memory disturbance, and an episode of sudden dizziness followed by a syncope that lasted for a few minutes. Neurological examination revealed slight right hemiparesis, right homonymous hemianopsia and left papilledema. A large cystic lesion was delineated at the temporal region in the plain CT, and no positively enhanced region could be found in the contrast enhanced CT. After surgical removal of the tumors, both cases were identified as cases of meningioma. They were diagnosed histopathologically as a fibroblastic meningioma and a meningotheliomatous meningioma respectively. The wall of the cyst consisted of the cortical surface per se in both cases. Preoperative diagnosis of such cases and the mechanism by which the cyst is formed were also discussed.

Regional hemocirculation and metabolism were evaluated in five patients with meningiomas using positron emission tomography (PET). Histological diagnoses were: two cases of meningotheliomatous type, one hemangiopericytic type, one fibroblastic type, and one transitional type. Regional cerebral blood flow (rCBF), blood volume (rCBV), oxygen extraction fraction (rOEF), and metabolic rates of oxygen (rCMRO2) and glucose (rCMRG1) were measured with 15O2, C15O. 15O2, and 18F-fluorodeoxyglucose tracers. For the quantitative analysis, regions of interest were delineated on tumors, the peritumoral region, and the contralateral gray matter in comparison with age-corresponding 5 malignant gliomas and 5 normal volunteers. Tumor hemocirculatory parameters (rCBF: 57.2 +/- 22.6 ml/100 ml/min, rCBV: 7.95 +/- 3.27 ml/100 ml, mean + SD, n = 5) were markedly higher than those of the contralateral gray matter (p less than 0.05 by a Student-t test). The high values were consistent with angiographic findings of tumor staining and with abundant tumor vessels demonstrated by pathological examination. rCMRO2 was 2.15 +/- 0.80 ml/100 ml/min, which were comparable to those of the contralateral gray matter. Tumor rCMRG1 showed 4.76 +/- 2.37 mg/100 ml/min; the values of two cases were similar to the respective gray matter. The raised metabolic rate (rCMRO2/rCMRG1) therefore suggests rather aerobic glycolysis as compared with gliomas. Low rOEF (0.26 +/- 0.16) reveals an excessive blood flow beyond oxygen demand of the tumor. In the peritumoral regions, rCBF and metabolism fell slightly but rOEF reached a level similar to the contralateral gray matter, possibly due to hemocirculatory stasis caused by intracranial hypertension; in contrast, an unmatched reduction of rCBF and rCMRO2 implies tumor cells infiltration in gliomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Thirty nine patients with diagnosis of meningeal leukemia, meningeal lymphoma and leukemia having high risk of meningeal involvement were treated with intraventricular administration of chemotherapeutic drugs via Ommaya reservoir. In all of those patients, radioisotope ventriculography was always performed with ytterbium-169 diethyltriamine pentaacetic acid (169Yb-DTPA) at 1 week after placement of the Ommaya reservoir. In the patients who had normal cerebrospinal (CSF) flow, majority of the radioactivity injected moved to cisterna magna and basal cistern at 4 hours after injection and to subarachnoid space of the cortical surface at 24 hours. Two cases of ventricular catheter occlusion were diagnosed by this method. Two cases of catheter tip misplacement were suspected with computed tomography and confirmed with radioisotope ventriculography. One of the misplacement cases developed focal leukoencephalopathy possibly due to high concentration of methotrexate (MTX) in the brain adjacent to the ventricular cathter. Two cases showed delayed CSF circulation, and the doses of MTX were decreased to be half of the ordinary dose (12 mg/M2 once a week) during initial phase of the treatment. The dose was increased after successful treatment of meningeal dissemination and restoration of the normal CSF flow. Radioisotope ventriculography might be quite useful for detection of the flow of materials placed into Ommaya reservoir. Routine use of this procedure may be helpful to prevent reservoir- and drug-related complications.

Peritumoral edema, a common occurrence in patients with malignant gliomas and meningiomas, is a major cause of morbidity and mortality. However, the causative mechanism of peritumoral edema has yet to be clarified. In this study, seventy patients with brain tumors (34 glioblastomas, 21 meningiomas and 13 metastatic tumors) were examined by CT scan with and without contrast medium infusion and by postoperative histologic verification in all cases. Peritumoral hypodensity areas on CT scan have generally been interpreted as cerebral edema. Peritumoral edema as seen in CT scan was classified into four grades according to the ratio of the largest diameter of tumor and the size of the zone of edema. Grade 0: no peritumoral low density area is seen in CT scan. Grade I: a small amount of peritumoral low density area is seen in CT scan. Grade II: a moderate amount of peritumoral low density area is seen is CT scan. Grade III: a large amount of peritumoral low density area is seen in CT scan. Twenty-five out of 34 glioblastomas and all of 15 metastatic tumors demonstrated moderate or severe peritumoral edemas such as Grade II or III. However 16 out of 21 meningiomas demonstrated mild peritumoral edemas such as Grade 0 or I. The grade of peritumoral edema was closely related to the degree of malignancy of the brain tumors. 8 out of 9 glioblastomas which demonstrated slight peritumoral edema, Grade I, had large cystic formations which seemed to serve as buffer action to compression mechanism by brain tumors. The grade of peritumoral edema was also related to the location of the tumor and venous involvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Methods: Either EMT Head Scanner, CT 1010 (slice thickness 10mm) or EMI Body Scanner, CT 5005 (slice thickness 13mm) was used. The concentration of metrizamide was 170-250 mgI/microliter and the amount was 7-10 microliters. Either lumbar puncture or lateral C puncture was made., Materials: 26 cases were included in this study. 1) disc disease: 11 cases, 2) spinal cord tumor: 6 cases, 3) Arnold-Chiari malformation: 3 cases, 4) atlantoaxial dislocation: 3 cases, 5) ossification of the posterior longitudinal ligament (associated with ossification of the ligamentum flavum): 2 cases (1 case), 6) spinal foreign body (acupuncture needle): 1 case., Results: 1) CT metrizamide myelography visualizes the subarachnoid space and makes it possible to know the lesion in the spinal canal in relation to the spinal cord in transverse plane. 2) It is difficult to determine the exact level of the lesion in axial plane. 3) The present technique does not allow to visualize the root sleeves. 4) It is difficult to delineate a compression of the subarachnoid space by small localized lesions (esp., disc diseases) due to overlapping the patent adjacent subarachnoid space within a slice 10 mm to 13 mm thick.

A 44-year-old farmer complained blurred vision and disturbance of recent memory. During his driving car traffic accident happened due to his right homonymous hemianopsia. On the 1st admission, neurological examination revealed choked disc(1 D.), hemianopsia, memory disturbance, dyscalculia, dyslexia and dysgraphia. The angiograms showed feeding arteries from left middle cerebral artery and posterior cerebral artery. Tumor vessels looked like cork-screw in the arterial phase and homogeneous tumor shadow was depicted in late venous phase. Contrast enhancement CT scan revealed a nodular homogeneous high dense lesion on the occipital region. Hemorrhage during every craniotomy was too much to remove and at last metastasized to left II rib and right VIII rib and right radius. Their histological examination reveals numerous endothelial-lined vascular channels and atypia of tumor cells with mitoses. Silver impregnation demonstrates networks of reticulum fibers surrounding the capillaries and tumor cells. Hemangiopericytoma in meninges forms entity and our case reports the WHO classification. Total removal should have to be done once for all by means of LASER (light amplification by stimulated emission of radiation).

A case of intrasylvian meningioma is presented with some considerations to the clinical, radiological, and pathological features of the tumor. A 34-year-old Japanese woman, who had experienced several episodes of fainting attacks since 19 years old, was admitted to our hospital on March 22, 1983. Her plain skull roentgenogram showed abnormal calcification in her left fronto-temporal region. CT scan demonstrated clear-marginal high density mass in the left sylvian fissure which was homogeneously enhanced after administration of contrast medium. Left carotid angiogram showed intrasylvian mass with small tumor stain in late arterial phase, but external carotid artery had no concern with this tumor. On March 30, left fronto-temporal craniotomy was performed. The tumor was located in the extra-axial space of the sylvian fissure without any attachment to the dura mater or to the choroid plexus of the ventricles. This hard tumor, 70 grams in its weight, was successfully removed. It was histologically diagnosed fibroblastic meningioma. The patient was discharged without any neurological deficits. Twenty-four cases of meningiomas not attached to the dura mater or to choroid plexus could be reviewed from the literature. This type of meningioma is occasionally called "deep sylvian meningioma", but in some reports the tumors developed far from sylvian fissure. And even in the cases in which the tumors were reported to be located in the sylvian fissure, macroscopic space where tumors developed was various. The clinical features, diagnosis, and surgical management of this tumor were also discussed in the report.

Dynamic computed tomography (CT) has been widely used because of its simplicity, but regional cerebral perfusion of brain tumors has not critically been evaluated. This study was conducted to evaluated parameters obtained from the dynamic perfusion study in brain tumors and to clarify the usefulness of the dynamic CT comparing with Xe-enhanced CT. Dynamic CT was performed on 20 patients with brain tumor (three meningiomas, one pineal tumor, three metastatic brain tumors, thirteen gliomas). Dynamic CT consisted of performing six rapid sequential scans after a bolus intravenous injection of 40 ml of iodinated contrast medium. In this study, five parameters (corrected first moment, area, peak, time to peak, percent terminal height) were obtained from computer analysed curve fit on time density curve profile of serial scanning. In Xe-enhanced CT, serial CT was taken every three or five minutes during inhalation of 40 to 50 percent stable xenon. Flow rate constant (K), partition coefficient (lambda) and cerebral blood flow (CBF) for each pixel were calculated from delta HU (Hounsfield unit) and end-tidal air curve and displayed on CRT as images. In patients with meningioma, values of area and percent terminal height of the tumor were much higher than those of contralateral gray matter, and these findings show excessive increase of the intratumoral blood volume and extreme extravasation of iodinated contrast medium respectively. In patients with metastatic brain tumor or malignant glioma, which were enhanced by contrast medium, the values of all parameters of the tumors were higher than contralateral gray matter. Increase of intratumoral blood volume and destruction of blood brain barrier are suggested in these tumors. In the remaining patients with glioma, which was not enhanced, the values of corrected first moment and time to peak of the tumors were higher but area and peak were lower than contralateral gray matter. These findings show decrease of intratumoral blood volume and delay of mean transit time and arrival time of the bolus. Compared with CBF measured by Xe-enhanced CT, it was suggested that high density area of metastatic brain tumor or malignant glioma consisted of viable tumor cells, and in patients with glioma, low density area adjacent to the tumor with contrast enhancement was the invasive site of the tumor. Using dynamic CT, we were also able to distinguish the tissue contains viable tumor cells from the other part of brain by the differences in the parameter value.

We report three cases of coincidental cerebral aneurysm with brain tumor. The incidence of such cases has been said to be 0.3 to 0.7% of all brain tumor cases, and, in our experience, has been 0.9% of 315 patients with brain tumor during the last decade. Case No. 1 was a 60-year-old female suffering from subarachnoid hemorrhage followed by left oculomotor nerve palsy due to rupture of left ICPC aneurysm, with left convexity meningioma which was found incidentally during preoperative cerebral angiography. Case No. 2 was a 47-year-old female suffering from headache, right exophthalmos, and bilateral papilledema. Preoperative CT scan and angiographies revealed right sphenoidal ridge meningioma and unruptured right middle cerebral aneurysm. Case No. 3 was a 28-year-old male with acromegaly. Pituitary adenoma and unruptured anterior communicating artery aneurysm were found preoperatively by CT scan and by angiography, respectively. All cases were well diagnosed preoperatively and surgically treated successfully.

A case of an anteriorly located meningioma in the region of the foramen magnum, successfully treated by a transoral approach, is reported. A 60-year-old woman was admitted to the author's department on January 19th, 1983. Six years before admission, she began to experience the gradual cold dysesthesia in the both palms, and then developed gait disturbance, clumsiness of the right hand and a stiffneck. She was found to have atrophied hands, mild spastic tetraparesis, ataxia and hypalgesia under the bilateral C2 spinal levels. A CT scan disclosed a patchy hyperdense lesion, which was enhanced homogenously with contrast medium, occupying almost all the intradural extramedullary space at the foramen magnum. The transoral approach was employed following preliminary tracheostomy. The tumor, extending about one centimeter superiorly to the basion and inferiorly to the upper border of C2 body, was removed completely, and then the dural defect was covered with a piece of fascia and gelform. An anterior occipitocervical fusion was performed extending to C2 using a block of an antogenous iliac bone. Post-operatively immobilization was secured by a Halo-Vest. But unexpectedly, CSF leakage was disclosed several days after the surgery without neurological deterioration. On the 17th day following first surgery, a re-operation was performed. The dural defect was successfully repaired with a piece of fascia by interrupted sutures in an illustrated fashion (Fig. 5). A piece of muscle was then placed in the epidural space created by bone removal. A fusion of the atlanto-axial joint not extending to the basiocciput was employed.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of intracranial multiple fibrous histiocytom is arising from the dura mater and both lateral ventricles is presented. To the authors' knowledge, this is the ninth case of intracranial fibrous histiocytomas reported in the literature. A 10-year-old girl was admitted with a 6 month history of cerebellar ataxia. Radiological examination including CT scan revealed a large mass in occipito-suboccipital region. On November 1, 1978, subtotal resection of the tumor was performed. Yellowish hard tumor, weighing 195 g had wide attachment to the dura mater, but did not invade the brain tissue. Postoperative CT scan, three months later revealed the other tumors in the left lateral ventricle and in the suprasellar region in addition to the lesion that had been operated on. In the course of hospitalization, the suprasellar tumor enlarged rapidly despite of 60Co radiation therapy, then led her to hypothalamic dysfunction. In January, 1981, she had paraplegia and paresis of the right upper extremity. Spinal lesion at the level of C-5 was presumed, but further examination was not performed because of her poor condition. On February 19, 1981, she expired. Autopsy of the head revealed four independent lesions in both lateral ventricles, the suprasellar region and the residual lesion which had been resected subtotally at the operation, respectively. Entire falx cerebri was invaded continuously by the tumor in occipito-suboccipital area. Microscopically, all tumors were identical in histology and were composed of spindle shaped cells with storiform pattern, foam cells and rare giant cells. Any mitotic figures were not detected. Clinical behavior was aggressive but histological figures suggested fibrous histiocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)

The computed tomogrpahy has been proved to be highly reliable in diagnosis of CNS diseases. The findings in 26 cases of metastatic brain tumors, and 2 cases of meningeal carcinomatosis performed with Hitachi CT-H scanner are analized. Metastatic tumors are seen on plain CT as mainly isodense nodules (60%). But, on enhanced CT, they increase in their density (97%). Larger nodules of metastatic tumors (over 2 cm in diameter) are tend to contain less dense central area, so called central cavitation. The direction of the expansion and/or extension of the perifocal low density is characteristic to the location of the tumor. In cases of meningeal carcinomatosis, diffuse periventricular higher density can be recognized enhanced CT.