Systematic MRI in NF1 children under six years of age for the diagnosis of optic pathway gliomas. Study and outcome of a French cohort.

BACKGROUND/PURPOSE: Optic pathway glioma (OPG) is the most common central nervous system tumor in children with neurofibromatosis type 1 (NF1), affecting 15-20% of patients. We reviewed the medical records of children systematically screened by ophthalmologic and MRI examinations to determine the influence of screening on the therapeutic management of children with OPG. METHODS: Data were collected on 306 newly diagnosed cases screened with systematic MRI from January 2001 to July 2007. In the OPG group, we distinguished the asymptomatic or symptomatic groups according to their initial status. RESULTS: Forty-five patients had confirmed OPG (14.7%). Thirty-six patients (80%) were asymptomatic and nine (20%) were symptomatic at the time of diagnosis with visual symptoms in six cases. The average age at OPG diagnosis was 3.4 years with six patients (13%) over six years old. Average follow-up was 7.7 years. Progression was observed in 16 cases (35%). Most patient conditions were managed conservatively (87%). Six children (13%) were treated with chemotherapy due to worsening visual function. All of these children had severe or mild visual impairment at the end of follow-up. CONCLUSION: Our study does not support a clear benefit of systematic MRI screening in NF1 children under six years old. Systematic neuroimaging in our study did not influence therapeutic management. Although OPG diagnosis was made early, treatment with chemotherapy did not improve the final visual outcome. If MRI remains the best tool for the diagnosis of cerebral and spinal pathologies in the NF1 population, our current study questions the usefulness of systematic MRI screening for OPG diagnosis. Conversely, this study suggests that the indication of neuroimaging should be dictated by the results of annual clinical and ophthalmological assessments.

Pre- and postnatal imaging of early cerebral damage in Sturge-Weber syndrome.

A case of prenatal diagnosis of Sturge-Weber syndrome associated with polymicrogyria is reported. The diagnosis was based on a unique association with unilateral hemispheric gyriform calcification, focal hemispheric atrophy and white matter changes on prenatal imaging including ultrasound and MRI. Polymicrogyria, which is exceptionally associated with Sturge-Weber syndrome, is suggestive of and reinforces the hypothesis of early impairment of the cerebral microvasculature related to leptomeningeal angioma, which may lead to abnormal cerebral development as early as the second trimester of pregnancy.