Short Communication

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Unexplained Loss of Vision in a Child: Consider Bilateral Primary Optic Nerve Sheath Meningioma Brigitte Holst2

Gertrud Kammler3

1 Department of Pediatrics, Clinic for Degenerative Brain Diseases,

University Medical Center Hamburg-Eppendorf, Hamburg, Germany 2 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany 3 Department of Neurological Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany 4 Institute of Neuropathology, University Medical Center HamburgEppendorf, Hamburg, Germany

Jakob Matschke4

Angela Schulz1

Address for correspondence Prof. Alfried Kohlschütter, MD, Children’s Hospital, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany (e-mail: [email protected]).

Neuropediatrics 2014;45:321–324.

Abstract

Keywords

► ► ► ►

optic nerve tumor optic nerve atrophy bilateral visual loss child

A 4-year-old girl gradually lost her vision to become practically blind at the age of 10 years. Examinations at several medical centers had been unable to establish an etiology. Traditional investigation using cerebral magnetic resonance imaging (MRI) initially showed normal results; however, later on it showed progressive atrophy of both optical nerves without recognizable cause. Subsequently, MRI including adequate orbital sequences, contrast-enhanced sequences, and fat suppression demonstrated bilateral primary optic nerve sheath meningioma, a rare but treatable tumor of childhood. The patient underwent neurosurgery and to date retains minimal vision. Adequate neuroradiological investigation of unexplained optic atrophy is advocated.

Introduction Primary optic nerve sheath meningioma (PONSM) has rarely been reported in children. It has been assumed that 4% of PONSM cases occur in patients younger than 20 years1–4 and are most commonly associated with neurofibromatosis type 2 (NF2).2,3,5 In a series of 150 NF2 patients, 5 had optic sheath meningioma, which was bilateral in 2 patients.6 In another study of 61 pediatric patients with NF2, 19 patients initially presented with symptoms of a meningioma.7 Typically, PONSM has a low rate of recurrence after treatment. Progression-free survival and overall survival are considered excellent.1 However, the course of PONSM in pediatric patients is reported to be more aggressive. If PONSM occurs bilaterally and is not promptly recognized, a total loss of vision may ensue.

received October 29, 2013 accepted after revision January 19, 2014 published online April 3, 2014

We report the case of a patient with bilateral vision loss due to a delayed diagnosis of PONSM not associated with NF2 and discuss the specific magnetic resonance imaging (MRI) techniques necessary for its diagnosis.

Case Report and Methods A 14-year-old female patient presented herself to our institution because of a progressive loss of vision over the past 10 years and a suspected degenerative brain disorder. She had no other health problems and was a good student. Because of unclear visual problems in her family, the girl had an ophthalmologic examination at the age of 6 months with normal results. Until the age of 4 years, further routine eye examinations yielded normal results. A decrease of vision was noted at the age of 4.5 years, when the girl sometimes, and in a very

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DOI http://dx.doi.org/ 10.1055/s-0034-1372303. ISSN 0174-304X.

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Miriam Nickel1 Ulrike Löbel2 Alfried Kohlschütter1

Bilateral Primary Optic Nerve Sheath Meningioma

Nickel et al.

variable way, did not recognize objects lying before her. Retrospectively, this difficulty is suggestive of initial visual field defects. Later on, she successively preferred closer distances to the television set and clearly lost visual acuity. Between the ages of 5 and 11 years, she was repeatedly examined at various pediatric, neurologic, and ophthalmologic institutions. Several MRI investigations, initially performed at the age of 5 years, reported normal optic nerves although she already had a severe loss of vision. Later on, progressive atrophy of the optic nerves without a recognizable cause was diagnosed. Leber hereditary optic neuropathy was genetically excluded. On examination, the healthy-looking patient revealed no pathological findings except a very poor vision that was restricted to the discrimination of light and dark. No signs linked to a central nervous system disorder and no cutaneous or spinal anomalies suggestive of neurofibromatosis were present. A standard MRI at our institution using axial T1- and T2-weighted images, fluid-attenuated inversion recovery and arterial and venous magnetic resonance angiography showed bilateral optic nerve atrophy, atrophy at the level of the optic chiasm, and contrast-enhancing lesions of the dorsal parts of the intraorbital optic nerves, suggesting bilateral PONSM (►Fig. 1). Additional sequences of the orbits were performed for better delineation of the expansion of the tumor including coronal fat suppressed T1-weighted imaging before and after the application of a gadolinium-based contrast agent (►Fig. 2). Although the patient was practically blind at that time, her ability to recognize light was very important to her. She therefore opted for surgical intervention to possibly maintain her residual vision. Bilateral nerve decompression through opening of the optic channel roof and partial resection of the tumor on the left side were performed uneventfully. The histopathological analysis revealed mostly acellular fibrous tissue infiltrated with small syncytial lobules consisting of atypical meningeal proliferates. The tumor cells showed monomorphous round to oval nuclei with occasional pseudoinvaginations. Mitoses were absent. Immunohistochemi-

cally, the tumor cells were strongly positive for the epithelial membrane antigen. The proliferation marker Ki-67 showed only occasional positively stained tumor cell nuclei with the Ki-67–labeling index not exceeding 3%. Molecular genetic analysis of tumor tissue was unsuccessful. A final diagnosis of meningothelial meningioma, World Health Organization grade I was made. As this tumor has been associated with NF2 in children,2,3,5 mutations in the NF2 gene were excluded by sequencing of promotor and all exon regions of this gene. Although the patient presented no stigmata of neurofibromatosis type 1, this diagnosis was also excluded by molecular genetic studies. Four years after the surgical intervention, the patient’s residual ability to faintly distinguish light and dark has remained stable. Recurrent episodes of headaches have remained. As a mosaic NF2 mutation is still possible,8 the patient remains under surveillance with yearly clinical and MRI examinations.

Discussion The patient suffered from a bilateral PONSM, a rare finding in children.1–3 This type of meningioma consists of a proliferation of meningothelial cap cells of the arachnoid villi within the optic nerve sheath, eventually strangulating the optic nerve. The typical symptom is a gradual, slow, and painless visual loss. Malignancy is rare and does not predict local invasive growth.5 Although our patient underwent repeated MRI examinations over several years, the diagnosis was missed initially. This led to blindness which might have been prevented by immediate stereotactic radiation therapy or surgical intervention.9,10 To adequately assess the optic nerves, a diagnostic MRI scan should include coronal and transversal views of the optic nerve in its entire length. Most importantly, a high in-plane resolution and thin sections of less than 3 mm should be used. In addition, fat suppressed T1-weighted images before and after the application of a gadolinium-based

Fig. 1 Magnetic resonance imaging (MRI) of bilateral primary optic nerve sheath meningioma without dedicated MRI sequences to adequately visualize the optic nerves. T2-weighted MRI using a slice thickness of 5 mm (A) shows a hypointense lesion of the dorsal part of the optic nerve on the left. On the right, the dorsal part of the optic nerve is not well delineated, but a tumor cannot be easily identified. Postcontrast T1-weighted images without fat saturation using a slice thickness of 3 mm (B) and 1 mm (C) show bilateral contrast-enhancing lesions, but only poor differentiation of the tumor extent. Neuropediatrics

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Fig. 2 Bilateral primary optic nerve sheath meningioma depicted using thin-section coronal T2-weighted images (A–C) and contrast-enhanced T1-weighted images with fat saturation (D–F). Note the improved visibility of the atrophy of the optic nerves (A, B) and the optic chiasm (C) on coronal images and the contrast-enhancing lesions of both optic nerves (D–F).

contrast agent are helpful to detect the lesion and to assess the tumor extent based on the characteristic injury to the blood–brain barrier.11,12 In conclusion, optical nerve atrophy in a child without a recognizable cause should prompt bilateral PONSM as differential diagnosis. Consequently, MRI investigation of the orbits requires dedicated orbital sequences including thin-section coronal views, fat suppressed T1-weighted imaging, and the application of a gadolinium-based contrast agent. These sequences are mandatory to detect rare, but potentially curable tumors such as PONSM.

Funding The Clinic for Degenerative Brain Diseases in Children is supported by Freunde der Kinderklinik UKE. This work has been presented in part at the Meeting of the Neuropediatric Society (GNP) in Mannheim, Germany, in September 2010.

Acknowledgments The authors thank Dr. Ellen Grant, Professor of Radiology, Harvard Medical School, Boston, Massachusetts, United States, for advice concerning diagnostic procedures. Dr. Victor-Felix Mautner, Professor of Neurology, University Medical Center Hamburg-Eppendorf, has kindly discussed the relation of findings in this patient to neurofibromatosis and has carried out molecular genetic studies.

Author Contributions M.N. and A.K. provided the case history and drafted the article. U.L. and B.H. described the neuroradiological methods and findings as well as reviewed and wrote the article. G.K. participated in the neurosurgical treatment of the patient as well as read and corrected the article. J.M. performed and described the neuropathological investigations as well as read and corrected the article. A.S. contributed to the diagnosis and care of the patient as well as read and corrected the article. Ethical Approval Written consent for publication was obtained from the patient having reached adulthood. Conflict of Interest The authors have no conflicts of interest to disclose.

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meningiomas of the first two decades of life. J Neurosurg 1994; 80(3):447–453 2 Harold Lee HB, Garrity JA, Cameron JD, Strianese D, Bonavolontà G, Patrinely JR. Primary optic nerve sheath meningioma in children. Surv Ophthalmol 2008;53(6):543–558 3 Menon G, Nair S, Sudhir J, Rao BR, Mathew A, Bahuleyan B. Childhood and adolescent meningiomas: a report of 38 cases and review of literature. Acta Neurochir (Wien) 2009;151(3): 239–244, discussion 244 Neuropediatrics

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surgery for optic nerve sheath meningioma. J Neurosurg 2010;113 (Suppl):28–33 10 Kotecha RS, Pascoe EM, Rushing EJ, et al. Meningiomas in children and adolescents: a meta-analysis of individual patient data. Lancet Oncol 2011;12(13):1229–1239 11 Turbin RE, Pokorny K. Diagnosis and treatment of orbital optic nerve sheath meningioma. Cancer Contr 2004;11(5): 334–341 12 Mafee MF, Goodwin J, Dorodi S. Optic nerve sheath meningiomas. Role of MR imaging. Radiol Clin North Am 1999;37(1): 37–58, ix

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Unexplained loss of vision in a child: consider bilateral primary optic nerve sheath meningioma.

A 4-year-old girl gradually lost her vision to become practically blind at the age of 10 years. Examinations at several medical centers had been unabl...
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