Gamma-knife surgery may be an effective alternative for treatment of central neurocytomas owing to its relative safety compared with conventional radiotherapy. In this paper we present results of gamma-knife treatment (GKS) of residual or recurrent neurocytomas. Twenty-two patients (14 female, 8 male) with recurrent or residual neurocytomas who underwent GKS were included. Diagnosis was based on histological findings. The proliferative potential of the tumors was examined by immunostaining with MIB-1 antibody, which is specific for detection of Ki-67 antigen. Tumor volume was determined by using post-gadolinium magnetic resonance images. After GKS treatment, MR imaging was scheduled at three-month intervals in the first year, at six months intervals in the second year, and yearly thereafter. Histopathological diagnoses were: 18 cases of central neurocytomas, two liponeurocytomas, one cerebral neurocytoma and one cerebellar neurocytoma. The MIB1 labeling index (LI) varied from 0 to 5.7%. Marked reduction in tumor volume was seen in 15 patients. In six patients, the tumor volume remained unchanged, and progression was observed for one patient. No complications because of GKS were noted. Shrinking effect on tumor volume increased with increasing duration of follow-up. On the other hand, high MIB labeling index did not seem to have an effect on tumor response to GKS treatment. Findings of this study suggest that GKS is an effective and safe treatment alternative for residual or recurrent neurocytomas. However, its effectiveness should be confirmed with larger studies.

Although prostaglandin E2 (PGE2) has been shown to be critical to hippocampal synaptic signaling and neuronal survival, it is still not clear which subtypes of PGE2 receptors (EPs) are expressed and how these EPs are regulated in the hippocampus. To address these questions, the expression of the EPs was profiled in the hippocampus. Messenger RNAs and proteins of the four receptors, EP 1-4, were detected both in the hippocampus and in the neocortex. EP 2 and EP 3 appeared in greater abundance, whereas EP 1 and EP 4 were barely detectable. EP 1, EP 2 and EP 4 were mainly colocalized with synaptophysin, suggesting the presence of EP 1, EP 2, and EP 4 in presynaptic terminals. It appeared that interleukin-1 beta increased the expression of EP 2 and EP 4 mRNAs. A blockade of synaptic transmission with either tetrodotoxin or MK-801 plus 6,7-dinitroquinoxaline-2,3-dione (DNQX) for 6 hr increased EP 3 and EP 4 mRNA, whereas high K(+) (90 mM) or 4-aminopyridine enhanced EP 2 and EP 4. The EP 1 level did not change significantly under these conditions. The expressions of EP 2, EP 4, and EP 3 were further elevated or reduced in neurons treated with high K(+) for 24 hr. However, mRNA of EP 3 was down-regulated in neurons treated with tetrodotoxin or MK-801 plus DNQX for 24 hr. In addition, both EP 2 and EP 4 mRNAs were up-regulated within 4 hr after high-frequency stimulation associated with long-term potentiation induction in hippocampal slices. Our results indicate that the four EPs are heterogeneously expressed in the hippocampus, and their expression is differentially regulated by neuronal activities, suggesting that EPs may actively participate in hippocampal synaptic transmission and plasticity.

ABSTRACTclosely related to the corpus callosum, which is often abnormal.These lesions make up approximately 0.1-0.5% of all intracranial lesions (9,11,16,17). They generally occur at midline structures like the corpus callosum and the quadrigeminal cistern (15,16). Two morphological types have been described; █ INTRODUCTION Intracranial lipomas are rare, fat-containing asymptomatic lesions that are generally considered as congenital malformations (16). The most common location is the close vicinity of the corpus callosum (CC), hence the name pericallosal lipomas. Pericallosal lipomas occur in the interhemispheric fissure AIM: A pericallosal lipoma is a fat-containing lesion occurring in the interhemispheric fissure closely related to the corpus callosum, which is often abnormal. This is the most common location for an intracranial lipoma. In this study, we aim to report on the clinical and radiographic aspects of ten patients diagnosed with pericallosal lipomas. MATERIAL and METHODS:A retrospective analysis of patients who presented to the neurology and neurosurgery outpatient clinics of Kayseri Training and Research Hospital between 2010 and 2014 revealed that 10 patients had the diagnosis of pericallosal lipoma. The clinical and magnetic resonance imaging data were obtained by reviewing their files. RESULTS:Ten patients with an average age of 35.8 years (11-80 years) were included in the study. The mean follow-up was 17 months (8-31 months). No neurological deficits related to the lesions were found during neurological examination in any of the patients. Four patients had tubulonodular lipomas while the other 6 presented with curvilinear lipomas. Four patients (40%) displayed a coexistent corpus callosum hypoplasia. In contrast to previous reports, 3 of these patients had a curvilinear lipoma while the remaining one had tubulonodular lipoma. Also, one of the patients displayed plaque lesions attributable to multiple sclerosis. During the follow-up period, no growth in the lipomas was recorded in any of the patients. No surgical intervention was performed as none of the patients displayed symptoms caused by the lipoma. CONCLUSION:In this study, we found a stronger association of corpus callosum hypoplasia with posteriorly situated curvilinear lipomas. Our results are in disagreement with previous studies, which suggested corpus callosum anomalies were more often associated with anteriorly situated tubulonodular lipomas. Pericallosal lipomas are benign, self-limiting or slow-growing lesions that generally remain asymptomatic. These lesions occur in the midline and surround critical neurovascular structures. Therefore, surgical intervention should be avoided in asymptomatic cases.

The treatment of glomus jugulare tumors represents a challenge for the neurosurgeon, since they invade major vessels and compress critical cranial nerves, resulting in significant morbidity from tumor resection. Among alternative and complementary treatment options, gamma knife radiosurgery is a less invasive procedure and may provide better protection of vital structures. This study aimed to evaluate the efficacy and long-term outcomes of gamma knife surgery in the treatment of these tumors in a large series with the longest follow-up period compared with previous reports. A total of 18 patients with glomus jugulare tumors that underwent gamma knife radiosurgery (GKS) were included. Eleven patients had a history of previous microsurgical treatment. The mean marginal radiation dose was 15.6 Gy (median 15 Gy, range 13-20 Gy). Patients were followed for a mean period of 52.7 months (median 41.5 months); the effect of gamma knife radiosurgery was evaluated using magnetic resonance (MR) images. Based on the last MR images, tumor control could be achieved in 17 out of 18 patients (94.4%). No complications such as radiation-induced peritumoral edema or radiation necrosis occurred. Neurological follow-up examinations revealed improved clinical status in ten patients (55.6%), stable neurological status in seven (38.9%), and deterioration in one patient (5.5%). At the last visit, 17 out of 18 patients were alive. Our results indicate that stereotactic radiosurgery is an effective and safe treatment modality in the management of glomus jugulare tumors, particularly for residual or previously untreated small tumors.

Solitary fibrous tumor (SFT) is a rare, benign, spindle cell tumor that is most commonly found in the visceral pleura. The orbit is one of the most common extrapleural sites of occurrence. Though they can be seen in any age, they typically present in adults with proptosis as the prominent symptom. They show no significant gender predominance. Orbital solitary fibrous tumors routinely exhibit a benign course, but malignant forms with an increased propensity for local recurrence have been reported. Histopathologically, they share similar features with hemangiopericytoma, which is much more common. The diagnosis of SFT depends on the diffuse and intense positivity of CD34 staining by immunohistochemistry (14). Here, we report a case of SFT, which presented with proptosis and double vision on lateral gaze. We describe the clinical, radiographic, histopathological, and immunohistochemical findings. We also provide a discussion on its origin and differential diagnosis in the light of relevant literature.

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Rarely, spinal gunshot injuries result in migrating intraspinal bullets. Use of MRI is controversial and other radiographic imaging might mimic an extradural bullet, even though it is intradural and migratory. Here, we present a case of spinal missile injury resulting in an intraoperatively mobile intradural bullet. The challenges faced during diagnosis and surgical removal are described. We also show that intraoperative ultrasonography may be useful in clarifying whether the bullet is intradural. A 32-year-old male presented with weakness and paraesthesia in his right leg following an accidental gunshot injury to his spine. Facet joint destruction and an intraspinal bullet were detected. Immediate surgical removal and transpedicular instrumentation was performed. The surgical procedure was complicated by lack of an identifying dural perforation at the bullet entry point and a gliding bullet inside the spinal canal during surgery. Gliding of the bullet was caused by the pushing effect of the bone rongeur and further gliding was avoided by performing the next laminectomy with an electric drill. Where other modalities indicated for a possible extradural location, intraoperative USG clearly showed the intradural position of the bullet and provided clear images without major artifacts. Surgical treatment of a mobile intradural bullet is challenging and open to surprises. Location of the bullet may shift as result of surgical procedure itself. Laminectomy should be performed with a power drill. Where fluoroscopy was inadequate and MRI not available, intraoperative USG proved useful in ascertaining the intradural versus extradural position of the bullet and allowed for a tailored dural opening.