Chiasmal Glioma Research Articles

Tumor bleeding from a de novo aneurysm associated with optic glioma

Aneurysms in children are rare and potentially devastating lesions. The authors report the case of a 16-year-old girl with a complicated medical history related to a chiasmal glioma diagnosed at 18 months of age. She had previously received multiple modalities of radiation treatment, including external beam, proton therapy, and Gamma Knife. She presented with hemorrhage centered in the tumor and extending into the ventricular space. There was no subarachnoid blood. Magnetic resonance imaging demonstrated the hemorrhage and tumor anatomy. Magnetic resonance angiography revealed an aneurysm at the internal carotid artery bifurcation, but the lesion was more clearly delineated on CT angiography. A comparison MR imaging study obtained 6 months earlier, even in retrospect, did not show evidence of an aneurysm. This case illustrates the salient point that the clinician must search for vascular lesions in the patient with spontaneous "tumor bleeding," especially if that patient has risk factors for aneurysm formation. The authors also suggest that a CT angiogram is better at radiographically demonstrating an intratumoral aneurysm than an MR angiogram in this scenario.

Glaucoma-like optic neuropathy in patients with intracranial tumours

To examine frequency and associated factors of glaucoma-like appearance of the optic nerve head in patients with intrasellar, suprasellar or parasellar tumours. This retrospective clinical observational study included patients who were consecutively treated for intrasellar tumours (n = 143), suprasellar tumours (n = 321), parasellar tumours (n = 36) or retrosellar tumour (n = 1), and all of whom had undergone fundus photography and full-threshold visual field examination. The tumour spectrum included 336 pituitary gland tumours, 32 meningiomas, 89 craniopharyngiomas, 9 chiasmal gliomas and 35 other types of tumours or lesions. An age-matched control group was formed from the population-based Beijing Eye Study. Using fundus photographs and visual field examinations, glaucoma was defined by a neuroretinal rim shape not following the ISNT rule (Disc glaucoma group) and by an abnormal rim shape plus glaucoma-like visual field defects (Field glaucoma group). Type and size of the tumours were assessed on neuroradiological images. Five-hundred and one patients fulfilled the inclusion criteria. Disc glaucoma and Field glaucoma were detected significantly more frequently in the study population [34 (6.8%) patients and 31 (6.3%) patients, respectively] than in the population-based control group of the same ethnicity (1.3% ± 0.5%; p < 0.001). In multivariate analysis, presence of Disc glaucoma [odds ratio (OR) = 2.64; p = 0.016] and presence of Field glaucoma (OR = 3.01; p = 0.027) were significantly associated with tumour location [suprasellar > parasellar > intrasellar]. The same held true for tumour width (OR = 1.08; p = 0.002; and OR = 1.08; p = 0.003, respectively). Large perisellar tumours were associated with a glaucoma-like appearance of the optic nerve head in eyes. It may diagnostically and pathogenetically be of importance.

Bilateral optic nerve drusen and gliomas in Klippel-Trenaunay syndrome

Klippel-Trenaunay syndrome (KTS) consists of a vascular nevus involving an extremity, varicosities of that extremity, and hypertrophy of bone and soft tissue. When arteriovenous malformation is also present, it is called Klippel-Trenaunay-Weber syndrome (KTWS). Ophthalmic features of these syndromes include vascular anomalies of the orbit, iris, retina, choroid, and optic nerve. We report a case of a 16-year-old girl with KTS who was found to have bilateral optic nerve and chiasmal gliomas, optic disk drusen, and acquired myelination of the retinal nerve fiber layer. These findings have not been previously reported to be associated with KTS or KTWS.

Gamma Knife surgery for optic glioma

Optic pathway/hypothalamic gliomas represent approximately 2%-5% of brain tumors in children. Total excision, subtotal excision, subtotal excision followed by irradiation, radiation therapy alone, chemotherapy, and no treatment at all have been reported. In this article the authors discuss the results of Gamma Knife surgery (GKS) for optic gliomas in 2 children. Two pediatric patients, a boy and a girl, underwent GKS for optic gliomas at our hospital between March 2005 and August 2005. The children's ages were 10 and 16 years at presentation. The histological diagnosis was confirmed to be pilocytic astrocytoma in both cases. The tumor involved the optic chiasm in 1 patient and the right optic nerve in the other patient. Treatments were planned with the prescription of 11 Gy to the 50% isodose line for the optic chiasm glioma and 15 Gy to the 50% isodose line for the optic nerve glioma. In both patients, GKS was well tolerated. The follow-up periods were 60 and 55 months. Complete response with near-total disappearance of the tumors was observed in both patients. During the follow-up period, neither of the patients developed any endocrine dysfunction. Gamma Knife surgery permits treatment of optic glioma with good tumor control and no clinically relevant morbidity. With the ability to deliver a high dose to the tumor while sparing normal brain tissue, especially the optic nerve, optic chiasm, and pituitary gland, GKS should be the choice of treatment for optic gliomas. A larger number of patients and long-term follow-up are required for further evaluation of the efficacy and potential side effects of GKS.

Acquired Monocular Nystagmus as the Initial Presenting Sign of a Chiasmal Glioma

A 15-month-old male presented with a one-day history of acute onset, continuous oscillating movement of his right eye. He had received his one-year immunizations four days prior and had a four-day history of a febrile viral respiratory tract infection. Pregnancy was unremarkable. He had severe iron deficiency anemia (MCV 66, Hb 65) and was developmentally delayed, as he was unable to stand independently and was non-verbal. His head circumference was 49 cm (95th percentile) and his weight was at the 25th percentile. On physical examination, continuous horizontal large amplitude pendular nystagmus of the right eye at a frequency of 3-4 Hz was observed. No nystagmus was observed in the left eye, even on funduscopic examination. The child could fixate targets in all four quadrants with both eyes independently, and could fixate and track small objects with both eyes independently suggesting no significant visual field defect or visual loss. Dilated funduscopic examination was normal, extra ocular movements were full, pupils were equal and reactive and there was no relative afferent pupillary defect. The remainder of the neurological examination was normal. There was no head bobbing or anomalous head position and no stigmata of neurofibromatosis type 1. Magnetic resonance imaging of the brain (Figure) demonstrated a 2 cm x 1.6 cm x 1.2 cm suprasellar enhancing mass involving the optic chiasm, hypothalamus, mamillary bodies and superior pituitary stalk. There was no extension into the pituitary fossa or the optic nerves and no ventricular enlargement. A biopsy of the mass was obtained and revealed histology consistent with a low-grade pilocystic astrocytoma (World Health Organization (WHO) grade 1), consistent with a diagnosis of chiasmal glioma.

Spontaneous regression of optic chiasmatic glioma in pediatric patients: When to intervene?

Spontaneous regression of optic chiasmatic glioma in pediatric patients: When to intervene?

Primary, non-exophytic, optic nerve germ cell tumors

Tumors of the optic chiasm are relatively uncommon and usually associated with phakomatoses such as neurofibromatosis. Even more rare is the presentation of a primary, non-exophytic, isolated optic chiasm germ cell tumor (GCT). These tumors have imaging characteristics nearly indistinguishable from optic chiasmatic gliomas (OCGs). Herein we describe two cases of young men who presented with similar findings of progressive, painless visual loss and hypothalamic-pituitary-adrenal axis dysfunction including diabetes insipidus. Brain imaging was non-diagnostic and suggestive of an OCG. Pathology demonstrated GCTs in each case highlighting the importance of biopsy confirmation of the diagnosis. Both patients underwent a pterional craniotomy and sub-frontal approach to the optic chiasm. The chiasm was diffusely enlarged and discolored in each case without evidence of sellar, suprasellar or perichiasmatic pathology. Pathology demonstrated a malignant mixed GCT in the first patient and a germinoma in the second. This case series highlights the importance of tissue biopsy for patients with progressive symptoms from optic chiasm tumors. Furthermore, this is the first report of a primary, non-exophytic malignant mixed GCT. As the treatment regimens differ widely between optic chiasm GCTs and chiasm gliomas, tissue diagnosis is important.

Improvement of diencephalic syndrome after partial surgery of optic chiasm glioma

A 10-month-old male presented with sudden growth failure and cachexia. MRI showed a chiasma of the hypothalamic mass. Biopsy was avoided due to operative risks. Three cycles of chemotherapy were given, resulting in stable disease on MRI, but growth failure despite attempts at enteral feeding. Surgical biopsy was then performed. A 30% tumor reduction was observed on post-operative imaging. Pathological examination revealed a pilocytic astrocytoma. After surgery, the child gained weight and his growth curve returned to normal. Enteral feeding was discontinued. After 4-year of follow-up, neurological development remains normal, with no residual or endocrine abnormalities.

Malignant Peripheral Nerve Sheath Tumors of Cranial Nerves and Intracranial Contents

Malignant peripheral nerve sheath tumors (MPNSTs) arising from cranial nerves or their branches are very uncommon. The literature consists mainly of isolated case reports and small series. We identified 17 such cases in 14 males and 3 females. With one exception, the tumors affected adults (age range 5 to 69 y, mean 39, median 32). Sites of involvement included vestibular nerves (n=6), vagal nerves (n=4), facial nerves (n=3) (1 centered in the geniculate ganglion), and 2 unspecified cranial nerves in the posterior fossa. In addition, 1 tumor involved the optic chiasm (n=1). Only 1 tumor arose in brain parenchyma of (frontal lobe). All but 3 lesions were intracranial. Five tumors arose in patients who satisfied clinical criteria for neurofibromatosis type 1 (NF1). One patient with a vestibular tumor and presumed NF2 had previously undergone resection of a contralateral vestibular cellular schwannoma. One posterior fossa tumor was a malignant melanotic schwannoma. Four patients had postirradiation malignant peripheral nerve sheath tumors, 2 having been treated for optic chiasm glioma, both being NF1 affected. One patient was irradiated for hypothalamic pilocytic astrocytoma and another for cervical Hodgkin disease. Identifiable precursor lesions included schwannoma (n=4), plexiform neurofibroma (n=2), and solitary intraneural neurofibroma (n=2). All tumors were histologically high grade (6 grade III and 10 grade IV). Three tumors showed heterologous elements, 2 osseous, and 1 rhabdomyoblastic. More often scattered than diffuse, S-100 protein staining was noted in 11 of 16 tumors and variable collagen IV staining in 10 of the 16. Immunoreactivity for p53 protein was diffuse and strong in 7 of 11 tumors. Twelve patients died within 17 months to 3 years of diagnosis, 1 was lost to follow-up, 2 are very recent cases, and 2 patients are currently alive, 1 after 2 recurrences, and another with spinal leptomeningeal metastases. Malignant cranial nerve sheath tumors are rare and are associated with the same poor prognosis as those of spinal nerves at other sites.

Prospective analysis of endocrine function in children with residual/recurrent low-grade brain tumours treated with high-precision stereotactic conformal radiotherapy

2049 Background: We report prospective neuroendocrine function in children and young adults with residual/recurrent low-grade brain tumours treated with high-precision stereotactic conformal radiotherapy (SCRT). Methods: 57 patients (median 13 yrs, range 5- 25 yrs; 42 male, 15 females) with low-grade brain tumours treated with SCRT comprise the present patient population. The histologic types included 18 craniopharyngioma, 16 optic chiasmatic glioma, 12 cerebral gliomas and 6 patients with cerebellar astrocytoma. Patients had undergone surgical procedure including biopsy in 19 and partial excision in 38 patients. Results: At a median follow-up of 27.5 months, 51 patients have controlled disease. Four patients have died of disease progression and 1 patient is alive with progression yielding 2 and 3 year overall survival of 90% and 85% respectively. Before starting radiotherapy, 30 out of 57 patients (53%) had hormone deficiency in at least one axis requiring replacement. This implies that factors other than radiotherapy such as tumour and surgery may also be responsible. Hormone dysfunction was significantly more in sellar tumour (27 of 38 patients, 71%; p=0.006) and tumours close to PHA (0.001). At baseline, hormone dysfunction was seen significantly more in GH axis (27 patients, 48%), corticosteroid axis (23 patients, 40%) than thyroid axis (10 patients, 17.5%) and sex hormone axes (1 patient, 2%). At 2- and 3-year follow-ups, hormone deficiency in at least 1 axis was seen in 14/29 patients (48%) and 11/22 patients (50%) respectively. At 2-year follow-up, three patients developed additional deficiency (1 each in thyroid, steroid and sex-hormone axis). At 3-year follow-up, only 1 more patient (14%) developed additional deficiency. Conclusions: More than half of patients with low-grade brain tumours before radiotherapy had hormone deficiency in at least one axis, with maximum deficiency seen in sellar tumours. Hormone dysfunction was seen in a very small number of patients at 2- and 3-year follow-ups in this cohort of patients treated with SCRT. Validation of these encouraging results will come from maturation of data in a larger number of patients at a longer follow-up. No significant financial relationships to disclose.

Spasmus Nutans-Like Nystagmus is Often Associated With Underlying Ocular, Intracranial, or Systemic Abnormalities

There is uncertainty as to whether spasmus nutans (SN) is an isolated idiopathic entity or whether there are underlying conditions that could cause or be associated with the nystagmus. We undertook this study to determine the frequency of ocular, intracranial, and systemic conditions in patients with nystagmus having characteristics of SN. We performed a chart review of 22 consecutive patients examined from 2000 through 2005 at the Dean McGee Eye Institute and Children' Hospital of Oklahoma with nystagmus consistent with SN. We collected information related to gender, age at presentation and age at final visit, visual acuity, refractive error, laterality of nystagmus, presence of head nodding and torticollis, pattern of strabismus, neuroimaging and electroretinography results, and other associated clinical findings. Visual acuity was reduced in 75% of eyes at presentation and 58% of eyes at last visit. Eight patients had significant refractive error. Seven patients had strabismus. Two patients had chiasmal gliomas. Four patients had cone or rod/cone dystrophy. Only three patients had no associated ocular, intracranial, or systemic conditions. A substantial proportion of patients presenting with SN-like nystagmus have important underlying ocular, intracranial, or systemic abnormalities that may require evaluation and management.

The Supraorbital Subfrontal Approach through an Eyebrow Skin Incision for Treatment of Anterior Cranial Fossa and Suprasellar Pathologies

We report our experience with a supraorbital eyebrow minicraniotomy. This technique is suitable for lesions situated in the region of the anterior fossa, suprasellar cisterns, parasellar region, and sylvian fissure. We have been using the supraorbital keyhole craniotomy since 1998 and have approached eight various lesions within the anterior cranial fossa and suprasellar space. Of the eight patients, six were treated for cranial base meningiomas, one for craniopharyngioma, and one for chiasmatic glioma. The approach has not been used for vascular pathologies. Except for the case of chiasmatic glioma, the total removal of the lesion was achieved in all cases and has been confirmed with mean 2.5-year follow-up MRI controls. The supraorbital craniotomy offers equal surgical possibilities with less approach-related morbidity owing to limited exposure of the cerebral surface and minimal brain retraction. In addition, the short skin incision within the eyebrow and careful soft-tissue dissection result in a pleasing cosmetic outcome.

Significant Improvement of Visual Functions after Removal of an Intracranial Giant Optic Nerve Glioma Revealing Exophytic Growth: Case Report

Intracranial giant optic nerve gliomas, usually presumed as optic chiasmatic gliomas, are much less common. The architectural tumor form of optic nerve glioma without neurofibromatosis type 1 is usually the expansile-intraneural pattern. The exophytic optic nerve gliomas without neurofibromatosis type 1 are relatively uncommon. Surgical decompression for intracranial optic gliomas frequently leads to clinical improvement, but obvious improvement of vision is rare. We report a case that demonstrated significant recovery of visual function after removal of the intracranial giant optic nerve glioma, revealing exophytic growth. A 13-year-old boy presented with visual impairment in both eyes. Magnetic resonance images (MRI) disclosed a 6 cm diameter mass in the suprasellar area. On heavily T2-reversed MRIs, it was obvious that the intracranial portion of right optic nerve was enlarged, and optic tracts were shifted to the left by the tumor. The relationship of the tumor to the chiasma could not be affirmed on MRIs. A right frontotemporal craniotomy for decompression of the optic apparatus was performed. After the majority of the tumor was resected, it became clear that the tumor originated in the right optic nerve. The tumor exophytically grew and dislocated the optic chiasma and optic tracts. Significant improvement of visual functions began from the first week after surgery and continued gradually thereafter. The histological diagnosis was pilocytic astrocytoma. A follow-up MRI taken 4 years after surgery showed no regrowth of the residual tumor. Giant exophytic gliomas without neurofibromatosis type 1 may arise from the intracranial portion of an isolated optic nerve. Direct visualization of optic component by heavily T2-reversed MRI could more precisely delineate the relationship of the intracranial optic nerve glioma to the optic apparatus. Surgery may be indicated in giant exophytic intracranial optic nerve gliomas and preoperative postulated optic chiasmatic gliomas. Microsurgical resection can induce postoperative visual improvement without regrowth of the residual tumor.

Twin and Triple Peaks Papilledema

To describe 2 adult patients who presented with papilledema after band atrophy (i.e., twin and triple peaks papilledema). Retrospective small case series. Two outpatients. Observations made on 2 patients whose cases were reviewed in the neuro-ophthalmology clinic. The first patient had a pituitary tumor presenting with papilledema, causing a triple peaks clinical sign. Color photographs, optical coherence tomograms, and magnetic resonance images are shown. The second patient developed twin peaks papilledema due to a chiasmal glioma causing secondary raised intracranial pressure. Twin peaks papilledema is a rare clinical sign that may develop in adults as well as in children. The first report and optical coherence tomography features of triple peaks papilledema illustrate a new clinical sign.

Natural history of neurofibromatosis 1-associated optic nerve glioma in mice

Neurofibromatosis is a common autosomal dominant disorder in which affected individuals are prone to the development of both benign and malignant tumors. Children with neurofibromatosis 1 (NF1), often develop low-grade astrocytic optic pathway tumors (optic pathway glioma [OPG]). One of the difficulties in managing children with NF1-associated OPGs is predicting which tumors will progress and result in visual or hypothalamic dusfunction. The authors previously developed a model of NF1-associated astrocytoma (GFAPCre; Nf1(flox/mut) mice) in which mice develop optic nerve and chiasm glioma.

Natural history of neurofibromatosis 1–associated optic nerve glioma in mice

Children affected with the inherited tumor predisposition syndrome, neurofibromatosis 1 (NF1), are prone to the development of low-grade astrocytic optic pathway tumors (optic pathway glioma [OPG]). Previously, we developed a model of NF1-associated astrocytoma (GFAPCre; Nf1(flox/mut) mice) in which mice develop optic nerve and chiasm glioma. To define the molecular pathogenesis of OPG, we used this mouse model to study the natural history of OPG formation using immunohistological and radiographic approaches. We observed that whereas astrocyte hyperplasia is present in the optic nerves associated with gross optic nerve thickening at 3 weeks of age, overt neoplastic changes were not seen until 2 months of age. Astrocyte proliferation was maximal between 3 weeks and 2 months of age, suggesting that the most rapid period of growth occurs early. Mouse OPG tumors were detected by magnetic resonance imaging at 2 months of age and exhibited contrast enhancement, as seen in human OPG. In addition, the mouse OPG tumors exhibited expression of proteins associated with astroglial progenitors, including nestin and brain lipid binding protein. Last, we observed neovascularization and microglial cell infiltration by 3 weeks of age before overt neoplastic transformation, suggesting that these cellular changes participate in the early stages of tumor formation.

High precision conformal radiotherapy employing conservative margins in childhood benign and low-grade brain tumours

Background and purpose To report local control and follow up outcome data of high precision conformal radiotherapy in childhood brain tumours. Materials and methods Between December 1999 and December 2002, 26 children (17 boys and 9 girls, median age 11.5 years) with incompletely excised or recurrent benign and low-grade brain tumours [13 craniopharyngiomas, 11 low-grade gliomas (LGG) and 2 others] were treated with three-dimensional (3D) conformal radiotherapy (CRT) (12 patients) and stereotactic conformal radiotherapy (SCRT) (14 patients). Gross tumour volume (GTV) included neuro-imaging based visible tumour and/or resected tumour bed. Clinical target volume (CTV) consisted of GTV+ 5 mm margin and planning target volume (PTV) consisted of additional 5 mm margin for CRT and 2 mm for SCRT. Treatment was delivered with 3–9 conformal fixed fields to a median dose of 54 Gy/30 fractions. Results The actuarial 2 and 3 year disease free and overall survival was 96 and 100%, respectively (median follow up: 25 months, range 12–47 months). Radiological follow up available in 25 patients revealed complete response in 1, partial regression in 10, stable disease in 13 and progression in 1 patient (within the CTV). One patient with craniopharyngioma on a routine imaging revealed a mild asymptomatic cyst enlargement, which resolved with conservative management. A patient with chiasmatic glioma developed cystic degeneration and hydrocephalus 9 months after SCRT requiring cyst drainage and placement of a ventriculoperitoneal shunt. Conclusion High-precision conformal techniques delivering irradiation to a computer generated target volume employing 7–10 mm 3D margins beyond the visible tumour and/or resected tumour bed appear to be safe in children with incompletely resected or recurrent benign and low-grade brain tumours, based on these data.

Frequency of mycoses in autopsy material

Pituicytoma is a rare low-grade tumor (WHO Grade I) of pituicytes involving the sellar–suprasellar region, and originating from the specialized glial cells of the neurohypophysis. Clinically and radiologically, they closely mimic pituitary adenoma or meningioma. Diagnosis requires histopathological examination of the resected tissue. This uncommon glial neoplasm is a rarity, with only 57 cases reported in the literature so far. We report three cases of pituicytoma (aged between 7 and 24 years) presenting with reduced vision, headache and features of hypercortisolism in one case. Radiologically, these lesions mimicked meningioma, hypothalamic chiasmatic glioma and pituitary microadenoma, respectively. The second case is a 7-year-old girl, the youngest case on record. Since this tumor is uncommon, it is frequently misdiagnosed. Awareness of this entity is essential for planning management and treatment. We present a brief review of all cases reported in the medical literature, and describe the clinical symptomatology, associated endocrinological abnormalities, imaging characteristics, behavior and outcome.

Management of Optic Chiasmatic/ Hypothalamic Astrocytomas in Children

The management of optic chiasmatic gliomas is controversial, partly related to failure to separate out those tumors involving the optic chiasm only (chiasmatic tumors) from those also involving the hypothalamus (chiasmatic/hypothalamic tumors). The purpose of this study was: (i) to analyze the outcomes of chiasmatic and chiasmatic/hypothalamic tumors separately; and (ii) to determine the appropriateness of recommending radical surgical resection for the chiasmatic/hypothalamic tumors. A retrospective chart review of all newly diagnosed tumors involving the optic chiasm from 1982-1996 at British Columbia's Children's Hospital was performed. There were 32 patients less than 16 years of age, 14 with chiasmatic and 18 with chiasmatic/hypothalamic astrocytomas, with an average duration of follow-up of 5.8 years and 6.3 years, respectively. Ten of the patients with chiasmatic tumors and none with chiasmatic/hypothalamic tumors had neurofibromatosis I. Thirteen of the 14 chiasmatic tumors were managed with observation only, and none had progression requiring active intervention. For the chiasmatic/hypothalamic tumors, eight patients had subtotal resections (>95% resection), six had partial resections (50-95%), three had limited resections (<50%), and one had no surgery. There were fewer complications associated with the limited resections, especially with respect to hypothalamic dysfunction. There was no correlation between the extent of resection (subtotal, partial, or limited) and the time to tumor progression (average 18 months). In conclusion, chiasmatic and chiasmatic/hypothalamic tumors are different entities, which should be separated out for the purposes of any study. For the chiasmatic/hypothalamic tumors, there was more morbidity and no prolongation of time to progression when radical resections were compared to more limited resections. Therefore, if surgery is performed, it may be appropriate to do a surgical procedure that strives only to provide a tissue diagnosis and to decompress the optic apparatus and/or ventricular system.

Stereotactically guided conformal radiotherapy for progressive low-grade gliomas of childhood

Purpose: To describe the rationale, technique, and early results of stereotactically guided conformal radiotherapy (SCRT) in the treatment of progressive or inoperable low-grade gliomas (LGGs) of childhood. Methods and Materials: Between September 1994 and May 1999, 14 children (median age 6 years, range 5–16) with LGG were treated with SCRT at the Royal Marsden NHS Trust. Tumors were located at the optic chiasm ( n = 9), third ventricle ( n = 2), hypothalamus, craniocervical junction, and pineal region (each n = 1). Four patients received chemotherapy before SCRT. Immobilization was in a Gill-Thomas-Cosman frame ( n = 12) and subsequently in a specially designed pediatric version of the frame ( n = 2). Stereotactic coordinates and the tumor were defined by CT scanning with a fiducial system and MRI fusion. The median tumor volume was 19.5 cm 3 (range 7.5–180). The planning target volume was defined as the area of enhancing tumor plus a 5–10-mm margin. The treatment technique consisted of 4 isocentric, noncoplanar, conformal, fixed fields. Treatment was delivered in 30–33 daily fractions to a total dose of 50–55 Gy. Results: SCRT was well tolerated, with transient hair loss the only acute toxicity. The median follow-up was 33 months (range 2–53). At 6 months after SCRT, 4 of 12 children with neurologic deficits improved and 5 remained stable. Twelve children were available for MRI evaluation. Two had a complete response, 6 a partial response, and 4 stable disease. One child with optic chiasm glioma had local progression at 25 months, and 1 developed diffuse leptomeningeal disease without local progression at 27 months. The 3-year local progression-free survival and overall survival rate after SCRT was 87% and 100%, respectively, compared with 89% and 98% for an historic control treated with conventional RT. New endocrine deficiencies were noted in 2 children after a follow-up of 20 and 23 months. Conclusion: SCRT is a feasible, high-precision technique of RT for children with LGGs for whom RT is considered appropriate. The local control and acute toxicity of SCRT are comparable to a historic control of patients with conventionally delivered RT. The frequency of delayed hypothalamic-pituitary axis dysfunction reflects tumor location adjacent to the hypothalamus and pituitary. Additional follow-up is required to demonstrate that SCRT contributes to a reduction in treatment-related late toxicity, while maintaining the local control achieved with conventionally delivered RT in children with progressive LGGs.