NFB-17. "Optic Pathway findings in children with Neurofibromatosis type-1 (NF-1)

BACKGROUND/OBJECTIVES:Optic-pathway-glioma(OPG) represents the most common central-nervous tumor in children with neurofibromatosis type-1(NF1), occurring at an incidence of 15-20%. It is estimated that 1/3 of NF1 patients(pts) with OPG will need treatment. DESIGN-METHODS:We performed a retrospective-review of all NF1-pts examined in the First Hellenic Multidisciplinary-Clinic – Center of Expertise for Neurocutaneous-disorders. Gender, age, MRI-radiological and ophthalmological findings, presence of OPG, management and outcome were analyzed. RESULTS:Since the establishment of the Clinic in 2016, 198pts with clinical diagnosis of NF1 based on NIH1988-criteria were evaluated and of them, 165(73 females, median age:5.5y, range:0.3-17.1y), who had imaging studies were included in this analysis. Eighty three pts(50.3%) had NF1-positive genetic-testing and 45NF1-family-history(27.3%). Imaging-findings from optic pathway were found in 55/165pts(28females). Percentage of pts with findings were 51.7% for <3y, 45.4% for 3-5y, 34.7% for 5-10y and 8.5% for >10y, respectively. The median age of their first brain-MRI imaging was 2.82y. Upon 1(st)MRI-imaging, 70.9% presented thickness of the optic nerves(ON)(25,4%bilateral, 20% optic chiasm,18.1% right ON, 10.0% left ON), 14.5%ON-tortuosity, 38.1%OPG(43,5% in the optic-chiasm) and 34.5% contrast enhancement. Of notice, 14pts presented an OPG after a median follow-up time of 1.79y. According to LGG2004-protocol indications for treatment, only 15/55pts had to be treated(27,2%, 5pts with family history, 33.3% between 5-10y). Severe vision-loss with need for immediate start of treatment upon 1(st)MRI imaging was found in 4pts, of whom 75% had family-history and first evaluation after the 5th year of age. Of notice, only 2pts<3y had to receive treatment, one with family-history and one with symptoms(diencephalic syndrome). CONCLUSIONS: Pts with NF1 should be followed by a multidisciplinary-team. Management should be individualized and imaging-studies can be limited to patients at high-risk. Positive family-history may be a negative prognostic factor for OP lesions.