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In a recent issue of Nature, Pan and colleagues explore whether light-induced stimulation of the optic nerve could influence the biology of optic gliomas. This study highlights the importance of neuronal-glioma interactions.

Although orbital tumors involving the optic nerve are rare, it is well-known that they are very likely to cause serious visual impairment in a patient. Unfortunately, at present, there are no effective interventions that can reliably preserve visual function while controlling tumor growth into intracranial spaces. To ensure visual function of the non-affected side, transection of the optic nerve together with the tumors involved is necessary in some cases. For this procedure large craniotomy and orbital unroofing are commonly utilized. As an alternative, we propose a novel surgical intervention for transection of the optic nerve having optic nerve tumors, which utilizes a lateral orbitotomy approach. To evaluate the invasiveness of different surgical approaches, we compared the days of hospitalization after surgery across patients who underwent the transcranial, lateral, and anterior approaches, respectively. We successfully removed 2 optic nerve tumors using the lateral approach, which required significantly shorter hospitalization than the transcranial approach. The transection of the optic nerve together with tumor removal by the lateral approach may be one of the novel surgical interventions for optic nerve tumors as this method is considerably less invasive than the transcranial removal method.

Introduction Moya-Moya angiopathy is a neurovascular disease that predisposes to ischemic or hemorrhagic strokes. It is generated by a steno-occlusion of the terminal portion of the internal carotid arteries, which induces the development of abnormal neovessels in the deep regions of the brain. Some pathologies such as sickle cell disease, Down syndrome or Graves’ disease may be associated with Moya-Moya angiopathy. These syndromic forms harbor several differences compared with idiopathic Moya-Moya disease. Case report We report the case of a young patient who presented with a syndromic form of Moya-Moya angiopathy after cranial radiation therapy for an optic glioma associated with type 1 neurofibromatosis treated by combined revascularization. We discuss the particularities of syndromic forms, in their presentation and management based on a review of the literature. Conclusion Many diseases can be associated with Moya-Moya syndrome. Symptomatic patients should undergo surgery, but the risk of postoperative complications appears to be greater than that encountered in patients with non-syndromic Moya-Moya angiopathy.

Neurofibromatosis type 1 (NF1) is a common neurogenetic disorder, in which affected individuals develop tumors of the nervous system. Children with NF1 are particularly prone to brain tumors (gliomas) involving the optic pathway that can result in impaired vision. Since tumor formation and expansion requires a cooperative tumor microenvironment, it is important to identify the cellular and acellular components associated with glioma development and growth. In this study, we used 3-D matrix assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) to measure the distributions of multiple molecular species throughout optic nerve tissue in mice with and without glioma, and to explore their spatial relationships within the 3-D volume of the optic nerve and chiasm. 3-D IMS studies often involve extensive workflows due to the high volume of sections required to generate high quality 3-D images. Herein, we present a workflow for 3-D data acquisition and volume reconstruction using mouse optic nerve tissue. The resulting 3-D IMS data yield both molecular similarities and differences between glioma-bearing and wild-type (WT) tissues, including protein distributions localizing to different anatomical subregions. Biological significance The current work addresses a number of challenges in 3-D MALDI IMS, driven by the small size of the mouse optic nerve and the need to maintain consistency across multiple 2-D IMS experiments. The 3-D IMS data yield both molecular similarities and differences between glioma-bearing and wild-type (WT) tissues, including protein distributions localizing to different anatomical subregions, which could then be targeted for identification and related back to the biology observed in gliomas of the optic nerve.

Objective To report a unique case of haemorrhagic presentation of a chiasmal and optic tract glioma (OPG) appearing as an extra-axial lesion on MRI scans. Case report A 30-year-old female with a preoperative radiological diagnosis of dermoid cyst was operated. No lesion was found in the chiasmal or carotid cisterns within the operative field. The right posterolateral corner of the chiasma and the beginning of the right optic tract appeared swollen. The area was incised and a haemorrhagic fluid poured through the opening. Several samples were taken and the pathological diagnosis was of pilocytic glioma. Conclusions We present a unique case of chiasmal bleeding into the optic pathway secondary to an optic glioma which radiologically mimicked an intracisternal cyst. In similar cases, rapid clinical evolution of the symptoms may be vital for the differential diagnosis. Surgery is warranted to prevent permanent damage to the visual pathway.

Pilocytic astrocytoma is a low-grade glioma that affects mostly children and young adults and can occur anywhere in the central nervous system. Pilocytic astrocytoma of the optic nerve is an equally indolent subtype that is occasionally associated with neurofibromatosis type 1. In earlier studies, this subtype was considered within the larger category of 'optic pathway glioma,' which included infiltrating astrocytomas and other hypothalamic tumors. However, there have been suggestions that gliomas in the optic nerve, and especially pilocytic astrocytoma of the optic nerve, are biologically different from tumors within the hypothalamus and other parts of the optic tract. Furthermore, the recent discovery of BRAF duplication and fusion with the KIAA1549 gene is reported to be more typical for posterior fossa tumors, and the rate of this aberration is not well known in pilocytic astrocytoma of the optic nerve. To determine the distinction of pilocytic astrocytoma of the optic nerve from pilocytic astrocytoma of the posterior fossa and to investigate the prevalence of BRAF aberrations, we reviewed the clinicopathological and molecular features of all such patients in our institution. Our study demonstrates that BRAF duplication is more frequent in posterior fossa tumors compared with pilocytic astrocytoma of the optic nerve (P=0.011). However, the rates of phospho-MAPK1 and CDKN2A expression were high in both pilocytic astrocytoma of the optic nerve and posterior fossa pilocytic astrocytoma, suggesting that the MAPK pathway is active in these tumors. Our study supports the notion that BRAF duplication is more typical of posterior fossa pilocytic astrocytoma and that molecular alterations other than KIAA1549 fusion may underlie MAPK pathway activation in pilocytic astrocytoma of the optic nerve.

SummaryThe concept that gliomas comprise a heterogeneous group of diseases distinguished by their developmental origin raises the intriguing possibility that neural stem cells (NSCs) from different germinal zones have differential capacities to respond to glioma-causing genetic changes. We demonstrate that lateral ventricle subventricular zone NSCs are molecularly and functionally distinct from those of the third ventricle. Consistent with a unique origin for pediatric low-grade glioma, third ventricle, but not lateral ventricle, NSCs hyperproliferate in response to mutations characteristic of childhood glioma. Finally, we demonstrate that pediatric optic gliomas in Nf1 genetically engineered mice arise from the third ventricle. Collectively, these observations establish the importance of innate brain region NSC heterogeneity in the patterning of gliomagenesis in children and adults.

The purpose of this study was to investigate the progression of changes in retinal ganglion cells and optic nerve glia in neurofibromatosis-1 (NF1) genetically-engineered mice with optic glioma. Optic glioma tumors were generated in Nf1+/- mice lacking Nf1 expression in GFAP+ cells (astrocytes). Standard immunohistochemistry methods were employed to identify astrocytes (GFAP, S100beta), proliferating progenitor cells (sox2, nestin), microglia (Iba1), endothelial cells (CD31) and retinal ganglion cell (RGC) axons (Neurofilament 68k) in Nf1+/-, Nf1(GFAP)CKO (wild-type mice with Nf1 loss in glial cells), and Nf1+/-(GFAP)CKO (Nf1+/- mice with Nf1 loss in glial cells) mice. Ultrastructural changes in the optic chiasm and nerve were assessed by electron microscopy (EM). RGC were counted in whole retina preparations using high-resolution, mosaic confocal microscopy following their delineation by retrograde FluoroGold labeling. We found that only Nf1+/-(GFAP)CKO mice exhibited gross pre-chiasmatic optic nerve and chiasm enlargements containing aggregated GFAP+/nestin+ and S100beta+/sox2+ cells (neoplastic glia) as well as increased numbers of blood vessels and microglia. Optic gliomas in Nf1+/-(GFAP)CKO mice contained axon fiber irregularities and multilamellar bodies of degenerated myelin. EM and EM tomographic analyses showed increased glial disorganization, disoriented axonal projections, profiles of degenerating myelin and structural alterations at nodes of Ranvier. Lastly, we found reduced RGC numbers in Nf1+/-(GFAP)CKO mice, supporting a model in which the combination of optic nerve Nf1 heterozygosity and glial cell Nf1 loss results in disrupted axonal-glial relationships, subsequently culminating in the degeneration of optic nerve axons and loss of their parent RGC neurons.

One of the major limitations to preclinical mouse therapeutic evaluation is the inherent difficulty in imaging small tumors in vivo. We present a rapid and reliable method to detect optic glioma (OPG) in a mouse neurofibromatosis-1 model (Nf1flox/mutGFAP-Cre mice) in vivo using Manganese-Enhanced Magnetic Resonance Imaging (MEMRI). In a blinded study, twenty-three mice were chosen randomly from a cohort of Nf1flox/mutGFAP-Cre mice and two sets of age-matched controls. In all cases, OPG presence or absence was correctly identified. In addition, the OPG size and shape was accurately measured in vivo, facilitating the use of this model for preclinical drug studies.

Gliomas of the optic pathways are rare childhood central nervous system tumors. The treatment approach is controversial because of its rarity and the slow and unpredictable growth rates of these lesions.We reviewed 50 patients with the diagnosis of optic pathway low-grade gliomas treated between January 1980 and December 1995 at King Faisal Specialist Hospital and Research Center, Saudi Arabia. Thirty-five patients presented with chiasmatic/hypothalamic (posterior tumors), and 15 with optic nerve gliomas with or without chiasmal involvement (anterior tumors). Evidence of neurofibromatosis was present in 18 patients. Twenty-nine patients underwent surgery (total or partial resection), and 12 of these received postoperative radiotherapy (RT). Sixteen patients were treated with primary RT. The radiation dose varied between 42 and 54 Gy (median dose 50).The overall actuarial survival rate was 87.5% at 5 years and 75% at 10 years, and the corresponding progression-free survival (PFS) rates were 69% and 62%. Patients with anterior tumors fared better than those with posterior tumors, with a 10-year PFS rate of 72% and 58%, respectively; the difference, however, was not statistically significant (p = 0.58). A PFS advantage was found in favor of patients with posterior tumors treated with RT (primary or postoperative) compared with no RT, with 5-year PFS rates of 68% vs. 42% (p = 0.03). This, however, did not translate into a survival advantage because of the success of salvage treatment.In multivariate analysis, age (3 vs.3 years) emerged as the only significant determinant for PFS with patients3 years old faring worse (p = 0.03). Neurologic and endocrine dysfunction are significant problems that need to be addressed.

Unidentified bright objects are commonly observed on magnetic resonance imaging in young neurofibromatosis 1 patients, but their clinical and pathologic significance is largely unknown. Diagnostic features of neurofibromatosis 1 include café-au-lait spots, intertriginous freckling, Lisch nodules, neurofibromas, bony lesions, and optic glioma. We investigated the relationship between unidentified bright objects and other features of neurofibromatosis 1. Data from the National Neurofibromatosis Foundation International Database included 523 neurofibromatosis 1 patients between 2 and 20 years of age who had cranial magnetic resonance imaging examinations. The presence or absence of unidentified bright objects, diagnostic features of neurofibromatosis 1, and central nervous system neoplasms was known in these patients. Logistic regressive models were used to measure associations between unidentified bright objects and the other features while controlling for age. The occurrence of unidentified bright objects was associated with the number of diagnostic features, but most significantly with central nervous system neoplasms other than optic gliomas [odds ratio (OR) = 9.0, 95% confidence interval (CI) = 1.2-70], optic gliomas (OR = 2.1, 95% CI = 1.2-3.6), subcutaneous neurofibromas (OR = 2.0, 95% CI = 1.3-3.1), and Lisch nodules (OR = 1.6, 95% CI = 1.1-2.3). These findings suggest a common causal mechanism between unidentified bright objects and these cardinal clinical features in children with neurofibromatosis 1.

Background Malignant optic glioma of adulthood is a rare, invasive neoplasm of the anterior visual pathway. In this article, the clinical features of a case series of 3 malignant optic nerve glioblastomas (World Health Organization grade IV) are presented, and the modalities of treatment and their associated survivals are discussed through a review of the existing literature to date. Methods A retrospective case series study was led for 3 patients diagnosed with primary optic nerve and chiasm glioblastoma, coming from 2 referral neurosurgical centers. An electronic search was conducted on MEDLINE via PUBMED, COCHRANE, from October 1973 to April 2016. Cohort, case reports, and case series were screened for investigating treatment and overall survival (OS) of malignant optic nerve gliomas. Pooled means and 95% confidence intervals of OS for each treatment were generated. Results From our retrospective case series, all patients had initial visual impairment (2 women and 1 man). The histologic diagnosis was done by biopsy. The patients' mean age was 67.3 years (standard deviation [SD] 18.5). The disease was rapidly lethal for all patients: median OS was 5 months (SD: 15.1). Two patients underwent chemotherapy by single cure of temozolomide, while the third one was treated with a radiochemotherapy protocol. Due to the fact that there is no gold standard treatment as first-choice treatment, a large heterogeneity in first-choice oncologic treatment is observed. However, we did not find any significant differences for OS between World Health Organization grade III and grade IV optic gliomas. Conclusion Malignant optic glioma is a rare and fatal disease in adults. Despite the modalities of treatment, the treatment outcomes remain unsatisfactory. There is no significant difference in the median OS of patients with malignant optic nerve, as compared with those diagnosed with other supratentorial glioblastoma. Chemoradiotherapy with temozolomide currently remains the best treatment in terms of OS. Advances in the understanding of tumor biology have yet failed to translate into effective treatment regimens.

The most effective method for the screening and monitoring of optic pathway gliomas in children with neurofibromatosis type 1 remains a dilemma. Children less than 6 years of age are the group at highest risk for the development of optic pathway gliomas. Although an annual ophthalmologic examination currently is recommended as the most efficient method to screen for optic pathway gliomas, this method is often unreliable and inaccurate in young children. Magnetic resonance imaging remains the most sensitive test; however, cost and the need for sedation or general anaesthetic preclude its use as a routine screening test. We previously have recommended visual-evoked potentials (VEPs) as a possible alternative or aid in the assessment of optic pathway gliomas in this group of patients. The aims of this study were to ascertain the sensitivity of VEPs in detecting optic pathway gliomas and to determine whether VEPs are useful in monitoring the progress of optic pathway gliomas. This study provides further evidence of the sensitivity of VEPs in detecting optic pathway gliomas. In addition, VEPs may provide additional useful information concerning the progression of optic pathway gliomas once they have been detected.

Advances have recently been made in the use of chemotherapy for pediatric brain tumors. Chemotherapy increases disease-free survival in high-risk primitive neuroectodermal tumor/medulloblastoma patients and enables the reduction of radiation therapy in standard-risk patients. Radiation can be significantly delayed and neurotoxicity ameliorated in many infants using chemotherapy. Chemotherapy can cause reduction in size of low-grade glioma, optic glioma, and oligodendroglioma. High-grade glioma and ependymoma are relatively chemoresistant. Physicians caring for children with brain tumors are encouraged to participate in controlled studies, so that objective information can be gathered and the role of chemotherapy in these tumors can be better defined.

A five-and-a-half-year-old boy with neurofibromatosis had bilateral orbital optic gliomas visible on magnetic resonance imaging. Both tumors displayed a double-intensity signal characterized by a circumferential area of CSF-intensity tissue surrounding and sharply delimited from a central linear core of opposite signal intensity. The peripheral CSF-intensity signal in orbital optic glioma correlates with the histopathological finding of perineural arachnoidal gliomatosis and serves as a neuroradiologic marker for neurofibromatosis.

Eighty-seven consecutive children with newly diagnosed optic glioma were managed at University of Toronto hospitals 1958–1990. Overall the 10-year survival, relapse-free survival and freedom from second relapse rates were 84%, 68% and 85%. Twenty-seven patients relapsed or progressed, of whom 40% were free of a second relapse 10 years after the first relapse. Fourteen patients had a second relapse. Thirteen are dead. None survived 5 years after second relapse. Patients with anteriorly located tumors (N = 35), which involved the optic nerve, or chiasm and optic nerves, fared better than those with posteriorly located tumors (N = 52) with spread beyond the chiasm, 10-year survival 95% versus 76%, (p = .02), 10-year relapse-free survival 80% versus 59% (p = .02), respectively. For posterior tumors primary irradiation was more effective than primary subtotal resection for prevention of subsequent relapse, 10-year relapse-free survival 75% versus 41% (p = .02), but salvage therapy was, in part, successful and multivariate analysis of prognostic factors influencing survival for posterior tumors indicated that neither primary resection nor primary irradiation were significant factors. For first relapse, primary irradiation and the presence of neurofibromatosis were the significant favorable factors. Since 1977 and for posterior optic glioma subtotal resection or surveillance were used in 21/29 (72%) patients compared with 4/23 (17%) previously. Ten-year survival rates before and after 1977 were 78% and 67% and 10-year relapse-free survival 64% and 56%, respectively.

This article describes the histology and location of brain tumors in young children as well as the presenting features of tumors in this age group and then focuses on three tumor types: medulloblastoma, ependymoma, and chiasmatic optic glioma. The discussion proceeds in terms of prognosis, late effects of treatment, and current and future strategies for treatment.

A case of ganglioglioma of the optic pathway associated with congenital exophthalmos and strabismus is presented. Since the tumor extended from the right optic nerve to the right geniculate body, it was diagnosed as an optic glioma before operation. However, optic nerve biopsy showed that the lesion was a ganglioglioma. Although a literature review yielded two previous cases of ganglioglioma of the optic pathway, this is the first case in which the tumor involved the whole optic pathway.

A progressive disturbance in visual acuity or visual field, along with an unexplained optic nerve atrophy, suggests the possibility of a tumor. Tumors that frequently affect the anterior visual pathway include primary optic nerve sheath meningiomas, intracranial meningiomas, optic gliomas, pituitary tumors, and craniopharyngiomas. The location of these tumors sometimes prohibits a complete surgical excision that might jeopardize the visual system. Radiation therapy, however, can be beneficial in these cases. This article reviews the indications for radiotherapy of tumors that involve the anterior visual pathway, along with the possible complications. Cases that present the effect of radiation therapy and radiation damage are presented.

Thirty-three patients with optic glioma seen over a 30-year period were reviewed. Five patients (15%) had tumor confined to the optic nerve, 8 patients (24%) had optic nerve and chiasmal involvement, and the remaining 20 patients (61%) had invasion of contiguous structures as well as chiasmal involvement. Eleven patients (33%) had a history of neurofibromatosis. Two-thirds of the patients had either a biopsy or a partial resection of the tumor, with the remaining one-third being clinically diagnosed. All patients received irradiation to local fields. The median dose was 5040 cGy in 160 cGy fractions. Of patients alive at last follow-up, the median time of follow-up was 12.3 years. The 5-, 10-, and 15-year overall actuarial survivals were 94, 81, and 74%, respectively. Univariate and multivariate analysis were performed on the following clinical variables: extent of primary tumor, extent of surgery, dose of radiation, gender, race, age, and presence or absence of neurofibromatosis. Extension of the primary lesion to the optic chiasm and age less. than or equal to 15 years were the only two variables to have statistically significantly inferior 15-year progression free survivals by multivariate analysis. Eighteen (55%) patients had treatment related complications with most involving the pituitary gland. We conclude that postoperative radiotherapy is beneficial in patients with chiasmal involvement and those with incomplete resections. A minimum tumor dose of 4000 cGy is recommended.

Three of ten children with optic gliomas satisfy the 1987 National Institutes of Health consensus criteria for neurofibromatosis type 1 (NF-1). The diagnosis in these cases is based on the presence of café-au-lait skin lesions in addition to the optic glioma. Two children without skin lesions have typical findings on magnetic resonance imaging (MRI) that also suggest a diagnosis of NF-1. A review of 281 NF-1 children with brain MRI results demonstrates the presence of these abnormalities in 57% of the cases. It is suggested that this MRI abnormality is sufficiently specific to add this feature to the list of diagnostic criteria. When MRI findings are present in a child with optic glioma and without skin lesions, counseling should be given for NF-1. It is noteworthy that these typical MRI findings in NF-1 are less common in adulthood, apparently because of spontaneous resolution.

Most of the clinical manifestations of NF1 are thought to occur in similar frequencies in different ethnic groups. One exception to this assumption may be optic glioma, which has been reported to be less common in African-Americans. We have compared the manifestations of NF1 in a retrospective analysis of 55 individuals with NF1, including 39 Caucasians and 16 African-Americans in the first part of the study. All patients met the NIH consensus criteria for NF1. The diagnosis of NF1 was established at the mean age of 11.1 years in African-Americans and 8.3 years in Caucasians (±SD 6.9 years for African-Americans and 12.3 years for Caucasians; p

The association of optic glioma with von Recklinghausen neurofibromatosis (NF) is well established. However, the incidence of these tumors in a large population of NF patients, prospectively evaluated with modern radiologic techniques, has not been established. We investigated the ophthalmic and intracranial features of NF in 217 patients aged 4 weeks to 69 years, in whom the diagnosis was based on stringent criteria. Tumors at various locations along the anterior visual pathway occurred in 15% of patients and were occasionally bilateral. The mean age of patients with chiasmal tumors was approximately 15 years less than patients with tumors of the optic nerve only. Two-thirds (67%) of all tumors were neither suspected historically nor detected by ophthalmologic examination. Neither the ophthalmoscopic absence of optic atrophy nor the normal results of roentgenograms of the optic foramina were reliable predictors of tumors detected by CT scan. The presence of optic glioma is not correlated to other ocular, skeletal, neurologic, or anamnestic risk factors.

INTRODUCTION Optic glioma occurs infrequently but is the subject of an extensive literature.R.‘0.‘2.‘4.20.2’ More than 500 cases have been reported in the last 150 years. Despite this extensive literature, English language references make only passing mention of megavoltage radiotherapeutic techniques and results. This report presents the role of radiotherapy in the management of primary gliomas of the intracranial optic nerves and chiasm.

We report two cases of the moyamoya syndrome which became clinically apparent after irradiation of an optic glioma during childhood. A summary of 14 cases of this syndrome following irradiation of intracranial tumors is also presented. Nine of these cases were optic gliomas; five were found in children with neurofibromatosis, another disorder that has a strong association with the moyamoya syndrome. The effectiveness of irradiation of optic gliomas in childhood is not definitely established. The possibility of inducing serious vascular disease is a further reason for caution when considering irradiating these tumors.

Monozygotic twins sisters with optic glioma "in mirror image" (one with involvement of the left optic nerve and the other with the right optic nerve) and hydrocephalus secondary to progressive stenosis of the aqueduct have been found in a series of 128 cases below 14 years of age with neurofibromatosis. The optic glioma was diagnosed in each of the twins at 2 years of age. In one twin the tumor involved only the optic nerve but in the other the glioma affected the optic nerve and spread to the homolateral zone of the optic chiasm. First symptoms of hydrocephalus appeared at 8 years and 11 years of age respectively but ventriculo-peritoneal shunting procedures were performed to relieve intracranial hypertension at 11 years and 15 years of age respectively. At 2 years of age both twins had pneumoencephalography which demonstrated normal air passage through the aqueduct and cerebral ventricles of normal size and morphology. Posterior studies with CT-scan demonstrated progressive obstruction of the aqueduct with very slow progression of the hydrocephalus in each twin, although it was not observed simultaneously. The increased intracranial pressure was tolerated for many years in each twin without obvious symptoms which could be attributed to the slow progression of the aqueduct obstruction.

Enlargement of the optic nerve and chiasm as demonstrated by high-resolution CT scanning or magnetic resonance imaging is often assumed to indicate tumor. However, this is not always true. The mode of clinical presentation of the disease process must be correctly applied to the interpretation of the radiographic studies. In the case illustrated here, neuro-ophthalmologic evaluation prevented an unnecessary biopsy in a patient whose presentation was atypical for anterior visual pathway glioma and whose clinical couse was otherwise compatible with optic neuritis.

A retrospective study was performed of 30 patients with optic gliomas referred to the Royal Marsden Hospital between 1951 and 1981. Twenty-nine of these had progressive disease, and were treated with radiotherapy. At presentation 12 (41%) had visual deficit to the extent of at least one blind eye. Visual acuity improved following treatment in 1'0 (43%) of 23 evaluable patients, was stable in 11 (48%) and deteriorated in 2 (9%). There was increase in visual fields in 4 (18%) of 22 evaluable patients, and no change in the remaining 18 (82%). Overall 26/29 (90%) of irradiated patients remained free from disease progression at a median follow-up period of 10 years. The probability of survival was 100% at five years following radiotherapy, and 93% at 10 years and also at 15 years. In view of the substantial morbidity and mortality in reported series, and the tendency for referral of more serious cases to a radiotherapy center, we conclude from our results that radiotherapy is effective in preventing progression of optic glioma, and that treatment early in the course of the disease is indicated to minimize the associated visual deficit.

There are four previously reported cases of post-irradiation calcification in the basal ganglia as demonstrated on the conventional skull roentgenograms. We have described two additional cases with grey matter calcification, which were demonstrated 10 and 14 yr after radiation therapy for an optic glioma and a medulloblastoma, respectively. The calcification was clearly demonstrated on CT scan, although it was not apparent on the skull roentgenogram. The extract pathogenesis of this condition is not clear. It appears, however, to be related to radiation vasculitis of the small vessels of the brain with resultant hyalinization and calcification. A long-term follow up study would be necessary to evaluate the significance and implication of post-irradiation calcification of the grey matter. CT is the most sensitive method of demonstrating the intracranial calcification in vivo.

Twenty-five children with optic gliomas were evaluated over a seven year period by sequential computed axial tomography in order to determine the efficacy of radiotherapy as a treatment modality. Indices of tumor progression or regression included both size and contrast enhancement characteristics. Twenty of 25 patients followed during this period received radiotherapy. Of these patients, ten had tumor regression, nine were stable, and one was worse. This result contrasts with five untreated patients, four of whom had tumor progression and one who was stable (x2 = 18.37, p less than .001). One of the children with tumor progression later received radiotherapy and demonstrated marked tumor regression. Of the 18 treated patients who could be tested reliably, visual function and/or regression occurred in seven children. None of the untreated patients improved. There were no definite complications of radiotherapy in this small group.

Eighty-five cases of histologically verified gliomas of the optic nerve or chiasm were studied retrospectively. Patient survival was analyzed according to location of tumor, treatment received, presence of neurofibromatosis, and degree of histologic anaplasia. Thirty-three patients had optic nerve tumors, and 52 had tumors involving the chiasm. Follow-up ranged from 6 days to 43.7 years. Of the 33 patients with optic nerve tumors, 28 (85%) survived a mean duration of 17 years, and survival was significantly associated with completeness of surgical excision. Twenty-three of the 52 patients (44%) with chiasmal tumors survived a mean duration of 19 years. Survival among patients with chiasmal tumors was unrelated to therapy received and was affected adversely by concomitant involvement of adjacent brain structures. The presence of neurofibromatosis conferred a protective benefit to patients with chiasmal tumors. No other significant factors could be statistically identified to influence the prognosis of patients with optic gliomas.

The rapid accumulation of radioactive glutamate was studied in human brain tumor cells grown in tissue culture. The MGH-LM line of human astrocytoma demonstrated both a high (apparent Km = 20 μM) and a low (apparent Km = 0.2mM) affinity component for the uptake of glutamate. The high affinity component was sodium-, temperature-, and energy-dependent and was present during the confluent (stationary) but not the log phase of cell growth. A study of confluent monolayer cultures of several other human brain tumors revealed that a similar high affinity uptake of glutamate occurred in 7 out of 8 malignant astrocytomas and appeared to be independent of the grade of malignancy. In 3 optic gliomas and 5 meningiomas studied, low but not high affinity uptake of glutamate was found. These studies suggest that glial cells in the human brain may in some instances possess uptake characteristics for glutamate similar to those previously ascribed to nerve endings.

Three infants with diencephalic syndromes had abnormally large hands and feet without general gigantism. In two of them the cause was an optic glioma involving the chiasma; in each instance the spinal fluid protein was increased. The third patient had brain atrophy, probably due to a perinatal lesion; the spinal fluid protein concentration was normal. In one patient growth of the tumor was accompanied by a change from emaciation to obesity and by disappearance of previous locomotor overactivity. The specificity of certain clinical manifestations in the diencephalic syndromes of infancy is discussed.

A 10-month-old girl presented with visual loss in the right eye associated with bilateral optic atrophy. The suggestive clinical diagnosis was an optic nerve glioma. The computerized tomographic findings were unusual in that symmetric bilateral involvement of the anterior visual pathways were present. The radiological diagnosis of an optic glioma was histologically confirmed.

Monocular and binocular visual evoked responses were obtained with a strobe flash, stimulating at 1.08 Hz. The flash was positioned 100 cm from the patient's nasion; 128 responses were averaged, with the amplifier pass band set at 0.3 to 300 Hz. The VERs were abnormal bilaterally, with significant delay when stimulating one or both eyes and with no. significant difference between the left and right eyes. An early positive peak between 60 and 76 msec occurred after stimulation of either eye, followed by a negative peak at 120 msec and the main positive peak at about 240 msec. Lateneies to single-eye stimulation were 80, 130, and 280 msec, respectively. ACT examination revealed a moderately large mass in the region of the optic chiasm, with uniform enhancement after intravenous injection of contrast material. Cortisol and growth hormone assays yielded normal results. A ehiasma[ astrocytoma was subtota[ly resected with the Cavitron Ultrasonic Surgical