An Atypical Paediatric Optic Nerve Sheath Meningioma.

A 16-year-old male presented with a three year history of right proptosis. All other ocular findings were normal. Imaging demonstrated a large, calcified, contrast-enhancing mass in the apical orbit. The tumour had high gallium-68-DOTATATE uptake and low 18F-2-fluoro-2-deoxy-D-glucose uptake. An incisional biopsy revealed a diagnosis of psammomatous optic nerve sheath meningioma (ONSM). One year later stereotactic radiotherapy was performed due to tumour growth. Tumour size and visual acuity remained stable in the six months after treatment. This case differs from previously reported paediatric ONSMs by its histo-clinical characteristics (exophytic-calcified mass, visual preservation, psammomatous histology).

Unilateral papilledema revealing an intracanalicular optic nerve sheath meningioma.

A 43-year-old female is referred to our clinic for evaluation of an incidentally discovered unilateral papilledema in her right eye of unknown cause. She had no past ocular or medical history. Examination revealed a corrected-distance visual acuity of 20/20 in both eyes. Posterior segment examination showed an elevated right optic nerve head with blurred edges. Ultrasonography failed to reveal optic disc drusen. Visual field testing showed enlargement of the blind spot in the right eye. Magnetic resonance imaging of the brain and orbit was done and revealed enlargement of the intracanalicular and prechiasmatic part of the right optic nerve and a diagnosis of a presumed right intracanalicular optic nerve sheath meningioma was made. She was managed conservatively and several years later remains asymptomatic.

[Results of fractionated targeted proton beam therapy in the treatment of primary optic nerve sheath meningioma]. / Résultats de la protonthérapie ciblée fractionnée dans le traitement des méningiomes primitifs de la gaine du nerf optique.

INTRODUCTION: Optic nerve sheath meningioma (ONSM) is a common benign neoplasm arising from the arachnoid tissue encapsulating the optic nerve and affects mainly middle aged women. It is a slow-growing tumor for which there is still no consensus on treatment. PURPOSE: To evaluate the safety and efficacy of fractionated targeted proton beam therapy (PBT) in the treatment of ONSM and to define its role in the treatment of these tumors. METHODS AND MATERIALS: We performed a retrospective analysis of 15 patients (13 women and 2 men), mean age 41.8 years, presenting with primary ONSM, followed at the Fondation Ophtalmologique Adolphe de Rothschild (Paris) between September 2006 and August 2013. After a multidisciplinary consultation, all were treated with PBT at a total dose of 52.2 Gy Eco, in fractions of 1.8 Gy Eco, at the Institut Curie (Paris). Patients underwent standardized follow-up including ophthalmologic examinations, visual field testing and imaging every 6 months. Study parameters were post-treatment visual acuity, tumor size on MRI, and treatment side effects RESULTS: We separated the patients into 3 distinct groups: patients treated by PBT after an observation period (4/15), patients treated by PBT after primary surgery (5/15) and patients treated by PBT as primary treatment (6/15). Visual acuity improved in 3 cases, deteriorated in 1 and remained stable in 11 cases. Tumor size on MRI remained stable in 100 % of cases following PBT. No serious adverse effects were recorded after a mean follow-up of 22.4 months (8-79 months). CONCLUSION: Our experience confirms the efficacy and the safety of proton beam therapy in patients with ONSM. PBT presents a promising alternative to surgery and conventional radiotherapy in the treatment of the MGNO. It seems to be effective in controlling tumor size and stabilizing visual function, at the cost of very low toxicity. Additional studies are needed to accurately determine the decision-making criteria and the ideal timing of this treatment.