Novalis radiosurgery of optic gliomas in children: preliminary report

AIM

To evaluate the effectiveness of Novalis radiosurgery (RS) in children with optic gliomas.

METHODS

Four pediatric patients (1 male and 3 female) were treated for optic gliomas with Novalis RS in our institution between February 2002 and July 2002. Their mean age was 12 (range 5-16) years at presentation for Novalis RS. The mean target dose was 44 (range 41-45) Gy, with a mean fractionation dose of 1.58 (range 1.5-1.65) Gy. Follow-up included magnetic resonance imaging and ophthalmologic and endocrine examinations.

RESULTS

The mean follow-up period was 54 (range 50-58) months. During the follow-up period, all patients were alive. Local control of the tumor was obtained in all patients. None of the patients showed clinically relevant morbidity, especially endocrine dysfunction.

CONCLUSIONS

Novalis RS may be an excellent treatment method for optic gliomas in children. However, long-term follow-up is required for further evaluation of efficacy and potential side effects.

[Pilomyxoid astrocytoma: a clinicopathologic study of three cases]

OBJECTIVE

To study the clinicopathologic features of pilomyxoid astrocytoma (PmA).

METHODS

The clinical and pathologic features in 3 cases of PmA were analyzed. Immunohistochemical study for glial fibrillary acidic protein (GFAP), CD34 and Ki-67 was performed on paraffin-embedded sections by standard EnVision method.

RESULTS

All the 3 cases occurred in female patients at the age of 10 months, 10 years and 19 years respectively. Two cases were located in the third ventricle, while the remaining case was located at the optic pathway. Histologically, the tumor was composed of bipolar spindle cells setting in a strikingly mucinous background. There was a marked proliferation of vessels within the tumor. In some areas, the tumor cells exhibited an angiocentric growth pattern. The biphasic pattern noted in a classic pilocytic astrocytoma was not found in PmA. Rosenthal fibers and eosinophilic granular bodies were also not identified. Immunohistochemcal study showed that the tumor cells were diffusely positive for GFAP. The Ki-67 labeling index measured less than 1%. CD34 highlighted mainly the vascular networks.

CONCLUSIONS

PmA is a distinctive variant of pilocytic astrocytoma with subtle histologic differences. Compared with conventional pilocytic astrocytoma, PmA behaves more aggressively. Some cases tend to occur in older children and adolescents. Immunohistochemical study for GFAP is helpful in differential diagnosis.

Sudden infant death due to neurofibromatosis type I

Sudden infant death syndrome (SIDS) is the unexpected death of an infant under the age of 1 year, where a complete autopsy, including scene investigation, fails to reveal a cause of death. Although the frequency of SIDS has decreased almost 50% over the past 10 years, it remains the leading cause of death in infants aged 1 to 6 months. SIDS is a diagnosis of exclusion and requires the elimination of a wide range of possible causes, including asphyxia, poisoning, abuse, occult heart disease, and other natural disease processes. In this report, we describe the case of an infant death initially suspected to be a SIDS death in which autopsy revealed an optic pathway glioma (optic glioma or hypothalamic glioma) and other stigmata of neurofibromatosis type I.

[A follow-up of patients with anterior optic tract glioma concurrent with type 1 neurofibromatosis]

Fifty-nine patients with anterior optic tract (AOT) lesion concurrent with type neurofibromatosis (NF-1) were followed up for 1 to 36 years (median 5 years). Based on the study, the authors identified several grades of the disease: - stabilization without intervention; - stabilization after treatment; - insignificant negative changes as a slight tumor growth and a further stabilization of the process; - occasionally negative changes irrespective of treatment. The behavior of a tumor is unpredictable. The onset of progression in infancy is a poor predictor. Ophthalmological symptoms are not the criterion that can be used to make a prognosis. The prognosis is largely determined by neurovisualization techniques and primarily magnetic resonance imaging. A uniform slight thickening of AOT structures irrespective of the extent of the process along the AOT should be referred to as a good prognosis. There was no spontaneous tumor regression in any case. By taking into account the beneficial effect of radiotherapy, the authors consider it expedient to use it as monotherapy and in combination with surgery. Bypass surgery on the spinal fluid system frequently fails to entirely solve the problem intracranial hypertension.

[Specific features of manifestation of anterior optic tract gliomas in patients with type 1 neurofibromatosis: ophthalmological and neurovisualizational aspects]

Gliomas of the anterior optic tract (AOT) (optic nerves, chiasms, and visual tracts) are benign slowly growing tumors usually detectable in childhood. These are a rather heterogenic group of tumors. The pattern and course of the disease are frequently affected by the presence of type 1 neurofibromatosis (NF-1) in the patient. The ophthalmological symptoms of AOT lesion in the presence of NF-1 were analyzed in 80 patients aged 1 to 24 years (median 5 years). According to the ophthalmological symptoms and the pattern and extent of lesions to AOT structures, the authors identified 4 groups by the data of neurovisualization techniques (magnetic resonance imaging, computed tomography) and revealed that the ophthalmological pattern reflected the site and degree of lesion to AOT structures. At the same time it is shown that there is a group of silent tumors attending without visual disorders. These tumors have the similar neurovisualization pattern, such as a moderate thickening of AOT structures and they occur in 13.8% of cases, as shown by the authors.

Spontaneous regression of optic pathways gliomas in three patients with neurofibromatosis type I and critical review of the literature

CASE REPORTS

The authors report their experience about three children (two girls, one boy; average age 1.6 years) with a spontaneous regression of optic gliomas. All of them had a previous diagnosis of neurofibromatosis type 1 (NF 1). None of them underwent surgery or biopsy nor received chemotherapy or radiotherapy. The complete regression was documented by MRI scans performed during a mean follow-up of 6.3 years.

LITERATURE REVIEW

Moreover, the authors analyze the features of the 16 cases previously reported in English literature of spontaneously regressed optic gliomas with an overview of the different therapeutic strategies. The knowledge that this kind of tumor, particularly in young patients, may regress is important in the decision of the best therapeutic approach.

Optic pathway glioma: outcome and prognostic factors in a surgical series

OBJECTS

The goals of this study were to evaluate the surgical outcomes of optic pathway glioma (OPG) and to analyze the prognostic factors related to the progression-free survival.

MATERIALS AND METHODS

A retrospective review was conducted on 33 patients who underwent surgery for OPG; these included 15 male and 18 female patients with a mean age of 8.3 years. The mean duration of follow-up was 52 months.

RESULTS AND CONCLUSIONS

The preservation rate of ipsilateral vision was 25%, while that of contralateral vision was 83% (P<0.001). There was no remarkable endocrine improvement after surgery. The overall and progression-free survival rates at 5 years were 93.6 and 52.4%, respectively. In our study, the predictors for tumor progression were children younger than 5 years of age (p=0.023) and of female gender (p=0.022). Because of the variable course of OPG, treatment policy should be optimized individually according to patient's status.

Vascularity and angiogenesis as predictors of growth in optic pathway/hypothalamic gliomas

OBJECT

The authors' aim in conducting this study was to investigate retrospectively the prognostic significance of angiogenic features in optic pathway/hypothalamic gliomas (OPHGs) in children.

METHODS

Patients were identified in whom a diagnosis of OPHG was made using pathological analysis at the Toronto Hospital for Sick Children between 1985 and 2002. Tumor specimens were reviewed for diagnostic accuracy and adequacy of the specimen. Sections were immunostained with factor VIII to assess microvessel density (MVD). A ratio of alpha-smooth muscle actin to factor VIII immunostaining was calculated to arrive at a vascular maturity index (VMI). Vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) immunostaining were performed to evaluate angiogenic factors. In addition, the MIB-1 labeling index (LI) was used to assess proliferation. These factors were evaluated with respect to progression-free survival (PFS). Forty-one of 60 patients originally identified had adequate samples and follow up for inclusion in the study. Of these, eight patients had coexisting neurofibromatosis Type 1. Twenty-eight patients experienced tumor progression after the initial treatment (surgery with or without adjuvant treatment). Thirty-eight patients are still alive. A high MVD (> 21 vessels/1.2 mm2) was associated with a significantly higher rate of progression compared with a low MVD (< 21 vessels/1.2 mm2; p = 0.017). Microvessel density was also predictive of reduced PFS on multivariate analysis stratified for extent of resection (p = 0.04), and VMI as well as intensity and distribution of VEGF and VEGFR staining and the MIB-1 LI were not significantly associated with PFS.

CONCLUSIONS

These findings suggest that MVD is the best current predictor of PFS in incompletely resected OPHGs. This information highlights the importance of angiogenesis in regard to low-grade gliomas.

Malignant optic nerve glioma (glioblastoma multiforme): A case report and literature review

Primary gliomas of the optic nerve are very rare. We report a case of a 59-year-old male with sudden vision loss diagnosed with malignant optic nerve glioblastoma multiforme. Magnetic resonance imaging revealed thickening of optic tracts, chiasm, and hypothalamus. Histologically, the tumor was composed of glial cells with pleomorphic nuclei and areas of vascular proliferation and necrosis. The patient died eight weeks after initial presentation. In addition to our case, 30 previously reported cases of malignant optic nerve glioma are reviewed.

Management of child optic pathway gliomas: new therapeutical option

OBJECTIVE

To present our experience in the treatment of child optic pathway gliomas in the last 25 years.

MATERIAL AND METHODS

Seventeen children under 10 years of age have been analyzed and assessed from clinic, ophthalmologic, endocrinologic, neurological, neuropathologic, and imaginologic points of view.

RESULTS

Predominance of female patients, 10 girls and 7 boys between 6 and 122 months old; mean age was 3 years and 8 months. The most frequent symptoms have been ophthalmologic and visual alterations in all 17 patients, endocrine alterations in 10, and neurological signs in 6. One of the patients presented neurofibromatosis type 1 (NF1), another patient had Down syndrome. Diagnosed using computed tomography or/and magnetic resonance imaging, histological studies showed pilocytic astrocytomas in 13 cases and a fibrillary astrocytoma grade II in 1 case. There were three patients without histological diagnosis; one of them had NF1. The treatment consisted of surgery, external beam radiotherapy, chemotherapy, and brachytherapy with iodine 125, separately or combined. Five patients died; the causes were secondary tumors in two children, tumor recurrence in one, sepsis secondary to respiratory and urinary tract infections in the child with Down syndrome, and finally, hydrocephaly due to hyperproteinorachia of tumor origin in one. Average survival was 89 months.

CONCLUSION

Chemotherapy and brachytherapy are therapeutic methods to be considered, especially in children under 5. Marsupialization of the residual cyst into the ventricular system postradio or oncolytic treatment through endoscopic or stereotactic techniques is useful in the treatment of endocranial hypertension and/or hypothalamic compression in these patients.

Magnetization transfer ratio and volumetric analysis of the brain in macrocephalic patients with neurofibromatosis type 1

The purpose of the study was to evaluate brain myelination by measuring the magnetization transfer ratio (MTR) and to measure grey (GMV) and white matter volume (WMV) in macrocephalic children with neurofibromatosis type 1 (NF1). Seven NF1 patients (aged 0.65-16.67 years) and seven age- and gender-matched controls were studied. A three-dimensional (3D) gradient echo sequence with and without magnetization transfer (MT) prepulse was used for MTR assessment. Volume measurements of GM and WM were performed by applying segmentation techniques on T2-weighted turbo spin echo images (T2WI). MTR of unidentified bright objects (UBOs) on T2WI in cerebellar white matter (52.8+/-3.3), cerebral peduncles (48.5+/-1.5), hippocampus (52.6+/-1.1), internal capsule (55.7+/-0.3), globus pallidus (52.7+/-3.9), and periventricular white matter (52.6+/-1.2) was lower than in the corresponding areas of controls (64.6+/-2.5, 60.8+/-1.3, 56.4+/-0.9, 64.7+/-1.9, 59.2+/-2.3, 63.6+/-1.7, respectively; p<0.05). MTR of normal-appearing brain tissue in patients was not significantly different than in controls. Surface area (mm(2)) of the corpus callosum (809.1+/-62.8), GMV (cm(3)) (850.7+/-42.9), and white matter volume (WMV) (cm(3)) (785.1+/-85.2) were greater in patients than in controls (652.5+/-52.6 mm(2), 611.2+/-92.1 cm(3), 622.5+/-108.7 cm(3), respectively; p<0.05). To conclude, macrocephaly in NF1 patients is related to increased GMV and WMV and corpus callosum enlargement. MTR of UBOs is lower than that of normal brain tissue.

Optic pathway gliomas

Optic pathway gliomas represent approximately 5% of all pediatric intracranial tumors. While these tumors are most frequently low grade astrocytomas, they follow a highly variable clinical course, and accordingly, there is much debate regarding their optimal management. Their propensity to occur in very young children and infants further complicates selection of therapy. Historically, surgery and radiotherapy have played a primary role in management, however, in the last 15 years, chemotherapy has evolved into the first-line treatment of choice. Nonetheless, chemotherapy frequently fails, but serves to delay implementation of radiotherapy or surgery until the child has progressed neuropsychologically. An overall favorable prognosis for this tumor emphasizes the need for careful selection of therapy. Herein, we review the major features of optic pathway glioma, including epidemiology, pathology, therapeutic interventions, outcome, and treatment sequelae.

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

OBJECTIVE AND IMPORTANCE:

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.

CLINICAL PRESENTATION:

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.

INTERVENTION:

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.

CONCLUSION:

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.

Optic-nerve gliomas, chiasmal gliomas and neurofibromatosis type 1

PURPOSE OF REVIEW

To review the most recent literature describing the natural history and disease progression patterns of optic-pathway gliomas in neurofibromatosis type 1 (NF1) patients. To aid in clarifying the current treatment patterns and follow-up recommendations.

RECENT FINDINGS

Contrary to prior documentation, current literature reveals that optic-pathway gliomas in NF1 can be diagnosed after the age of 6, and may progress until the age of 12. The disease progression occurs most frequently in the first two years following diagnosis.

SUMMARY

Optic-pathway gliomas in NF1 can display a variety of manifestations and exhibit an unpredictable disease course. No specific characteristics have been found thus far to predict an aggressive compared with indolent disease course. Recently primary diagnoses of optic-pathway gliomas have been made in children aged six or older, and have been shown to progress until the age of 12. Although large-scale studies are required to change current follow-up recommendations, the data suggest that NF1 patients should be vigilantly evaluated for optic-pathway gliomas past the age of 12.

Neurosurgical implications of neurofibromatosis Type I in children

Neurofibromatosis Type 1 (NF1) is one of the most common inherited diseases in humans. It is caused by a mutation in the NF1 gene on chromosome 17, and is associated with numerous central and peripheral nervous system manifestations. Children with NF1 are at high risk of harboring numerous lesions that may require the attention of a neurosurgeon. Some of these include optic nerve gliomas, hydrocephalus, intraspinal tumors, and peripheral nerve tumors. Although most of the neoplasms that affect the brain, spine, and peripheral nerves of children are low-grade lesions, there is a small but real risk that some of these lesions may become high grade over time, requiring other forms of therapy than surgery alone. Other associated disorders that may result from NF1 in childhood include Chiari malformation Type I, scoliosis, and pulsating exophthalmos from the absence of the sphenoid wing. In this review, the major lesions that are found in children with NF1 are reviewed as well as the types of treatment that are offered by neurosurgeons and other members of the treating team. Today, optimum care of the child with NF1 is provided by a multidisciplinary team comprising neurosurgeons, neurologists, ophthalmologists, radiologists, orthopedic surgeons, and plastic surgeons.

Ophthalmological manifestations in VHL and NF 1: pathological and diagnostic implications

Von Hippel-Lindau disease (VHL) and neurofibromatosis type 1 (NF 1) are hereditary multitumor syndromes that show associated ocular manifestations. Capillary retinal angioma, a benign vascular tumor, is the classical ocular lesion in VHL. It often appears as the first manifestation of the disease and may thus lead to the diagnosis of VHL. Since small angiomas can be treated easily by laser photocoagulation, a regular ocular screening of VHL patients is recommended. Ocular manifestations of NF 1 are more diverse as compared to VHL. Lisch nodules of the iris are an important diagnostic criteria of NF 1 since they can be found in almost every affected patient. Optic glioma can occur both intraorbitally and intracranially. The intraorbital form causes progressive protrusion of the globe and eventually blindness. Extension of the tumor beyond the chiasm worsens the prognosis quoad vitam. The hallmark of NF 1, namely cutaneous neurofibroma can cause visual impairment when affecting the skin of the eyelids. The rare intraorbital pexiform neurofibroma is associated with abnormal development of the orbital bones and infantile glaucoma. It may result in orbital mass effects and therefore may need surgical excision.

Visual changes after gamma knife surgery for optic nerve tumors

Tumors involving the optic nerve (optic glioma, optic nerve sheath meningioma) are benign but difficult to treat. Gamma knife surgery (GKS) may be a useful treatment. The authors present data obtained in three such cases and record the effects of GKS.

Primary tumours of the optic nerve and its sheath

PURPOSE

To describe the clinical, neuroimaging, and pathologic features of primary tumours of the optic nerve and its sheath.

METHODS

Review of published cases and personal series.

RESULTS

The most common primary tumour of the optic nerve is the benign glioma. This low-grade astrocytoma usually can be followed without intervention. Progression of visual symptoms and signs may necessitate either surgery to remove the tumour or radiation therapy. The most common tumour of the optic nerve sheath is the meningioma. The optimum treatment for this lesion is stereotactic or three-dimensional conformal fractionated radiation therapy, which generally results in stabilization or improvement in vision. A variety of other primary tumours may mimic, in both manifestations and imaging appearance, the more common glioma or meningioma. In such cases, the correct diagnosis may not be made until a biopsy is performed or the nerve is removed.

CONCLUSION

Primary tumours of the optic nerve and its sheath are not uncommon. Diagnosis can often but not always be made by the results of a complete examination combined with imaging studies, particularly CT scanning and MR imaging. Management depends on the presumed or histologically verified nature of the tumour.

The use of 19F spectroscopy and diffusion-weighted MRI to evaluate differences in gene-dependent enzyme prodrug therapies

To evaluate noninvasive measures of gene expression and tumor response in a gene-dependent enzyme prodrug therapy (GDEPT), a bifunctional fusion gene between Saccharomyces cerevisiae cytosine deaminase (CD) and Haemophilus influenzae uracil phosphoribosyltransferase (UPRT) was constructed. CD deaminates 5-fluorocytosine (5FC) to 5-fluorouracil (5FU), and UPRT subsequently converts 5FU to fluorouridine monophosphate, and both of these reactions can be monitored noninvasively in vitro and in vivo using 19F magnetic resonance spectroscopy (MRS). Following transient transfection the CD-UPRT fusion protein exhibited both UPRT and CD enzymatic activities as documented by 19F MRS. In addition, an increase in CD activity and thermal stability was witnessed for the fusion protein compared to native CD. Stable expression of CD-UPRT in 9L glioma cells increased both 5FC and 5FU sensitivity in vitro compared to CD-expressing and wild-type 9L cells. Noninvasive 19F MRS of both CD and UPRT gene function in vivo demonstrated that in animals bearing CD-expressing tumors there was limited conversion of 5FC to 5FU with no measurable accumulation of cytotoxic fluorinated nucleotides (F-nucs). In contrast, CD-UPRT-expressing tumors had increased CD gene activity with a threefold higher intratumoral accumulation of 5FU and significant generation of F-nucs. Finally, CD-UPRT yielded increased efficacy in an orthotopic animal model of high-grade glioma. More importantly, early changes in cellular water mobility, which are felt to reflect cellular death, as measured by diffusion-weighted MRI, were predictive of both durable response and increased animal survival. These results demonstrate the increased efficacy of the CD-UPRT GDEPT compared to CD alone both biochemically and in a preclinical model and validate both 19F MRS and diffusion-weighted MRI as tools to assess gene function and therapeutic efficacy.

Ophthalmic artery occlusion secondary to radiation-induced vasculopathy

A 35-year-old man with neurofibromatosis type 1 (NF1) had a left ophthalmic artery occlusion that caused no light perception OS 28 years after having been treated with external beam radiation therapy for a presumed glioma of the right optic nerve and chiasm. Clinical and imaging findings were consistent with radiation-induced cerebral vasculopathy. This ophthalmic complication has never been reported, despite the common occurrence of severe carotid-ophthalmic artery junction stenosis after radiation in NF1 patients. Even though modern radiation techniques limit collateral damage, this modality should be used with discretion in NF1 patients, given the vulnerability of their immature cerebral vasculature to radiation.

Optic nerve glioma and colonic polyposis: report of a new association

AIM

The authors describe the clinical, radiological and histopathological features of an optic nerve glioma associated with colonic polyposis. The association between colonic polyposis and neuroepithelial tumours of the central nervous system has been previously described, but no association with optic nerve gliomas has ever been reported.

METHODS

We report a 14-y-old girl with colonic polyposis and unilateral proptosis for whom an excisional biopsy of the orbital lesion was performed.

RESULTS

Histopathological evidence of juvenile pilocytic astrocytoma grade 1 was detected. Correlation with criteria for Turcot's syndrome was established.

CONCLUSION

Optic nerve tumours should be included in the spectrum of central nervous system lesions associated with colonic polyposis.

Recent advances in optic nerve glioma with a focus on the young patient

PURPOSE OF REVIEW

Optic tract low-grade gliomas are one of the commonest category of neoplasm presenting in childhood and early adolescence. Recent reports covering their aetiology, imaging techniques, the application of novel radiotherapy techniques and chemotherapy are reported.

RECENT FINDINGS

These tumours are increasingly being seen as markers of enhanced risk in patients and their families for the subsequent development of central nervous system tumours. Modern imaging techniques are being explored for their diagnostic sensitivity and specificity as well as their ability to describe, with greater precision, anatomical boundaries in order to minimize, through conformal techniques, radiation doses to organs at risk within the brain. Increasing numbers of trials of chemotherapy agents are demonstrating efficacy in this tumour category.

SUMMARY

Visual pathway low-grade astrocytomas of childhood are the subject of diverse research into diagnostic aetiological and treatment aspects aimed at tailoring diagnostic and treatment procedures more precisely to the needs of the young patient for this tumour type.

Unilateral adult malignant optic nerve glioma

INTRODUCTION

Adult malignant optic nerve gliomas are rare and rapidly fatal visual pathway tumours. They represent a clinical entity different from the more common childhood benign optic nerve gliomas, which are frequently associated with neurofibromatosis I.

CASE REPORT

A 61-year-old woman presented with rapidly progressing right vision loss, lower altitudinal visual field defect and papilloedema. MRI showed intraorbital and intracranial swelling of the right optic nerve. Resection of the intracranial part of the right optic nerve up to the chiasm revealed anaplastic astrocytoma grade III. Within 1 year, the patient died of leptomeningeal metastasis despite radiotherapy. Clinical and MRI evaluation of the left eye and optic nerve were normal at all times.

DISCUSSION

Unilateral adult malignant glioma of the optic nerve is exceptional. The final diagnosis was only confirmed by optic nerve biopsy. In the literature, only one patient has been reported with a unilateral tumour manifestation; he was lost to follow-up 3 months later. All other cases were bilateral. To date, 44 case reports of adult malignant optic nerve glioma have been published, either malignant astrocytoma or glioblastoma. These tumours can mimic optic neuritis in their initial presentation. The diagnosis is seldom made before craniotomy. On MRI images, malignant glioma cannot be distinguished from optic nerve enlargement due to other causes. Although radiotherapy appears to prolong life expectancy, all presently available treatment options (radiation, surgery, radio-chemotherapy) are of limited value. Most patients go blind and die within 1 or 2 years.

Optic radiation involvement in optic pathway gliomas in neurofibromatosis

PURPOSE

Optic pathway gliomas (pilocytic astrocytomas) in neurofibromatosis type 1 (NF-1) typically involve some combination of the optic nerves, chiasm, or optic tracts. Involvement of the optic radiations is rare.

DESIGN

This paper describes seven patients with NF-1 with gliomas involving the pregeniculate optic pathway in addition to the optic radiations.

METHODS

A retrospective database review was made of all patients with NF-1 and optic pathway gliomas seen by one of the authors (G.T.L.) at the Children's Hospital of Philadelphia from July 1993 to October 2001. Patients with involvement of pregeniculate optic pathway and the optic radiations were identified. From November 2001 to February 2003, patients were sought prospectively. Cases were also identified from the practice of another author (M.C.B.) at Arkansas Children's Hospital.

RESULTS

Four patients from Children's Hospital of Philadelphia (three of 83 total NF-1/optic pathway gliomas from July 1993 to October 2001 and one prospectively) and three from Arkansas Children's Hospital were identified. Two had expanding mass lesions within the white matter of the temporal or parietal lobes, which were histopathologically demonstrated to be pilocytic astrocytomas. The other five had radiographic involvement of the optic radiations but did not undergo biopsy. In three of the cases the vision was 20/200 or worse in each eye.

CONCLUSIONS

Optic pathway gliomas in NF-1 may rarely involve the optic radiations. Optic radiation involvement may signal a more aggressive optic pathway glioma in patients with neurofibromatosis-1.