Edema of the optic tract in patients with tumors of the sellar region: clinical and visual implications in the pediatric population

OBJECTIVE Tumor-related edema of the optic tract (EOT) corresponds to a preferential posterior distribution of peritumoral edema along the white matter tract of the visual system. To date, the consequences of EOT have never been evaluated specifically in the pediatric population. In this study, the authors attempted to identify clinical and radiological features associated with the development of EOT and the specific influence of this edema on visual function. METHODS A retrospective review was performed of data collected from patients younger than 18 years who underwent surgery for a tumor in the sellar region at the authors' institution between January 2005 and January 2016. Data were collected on patient characteristics, ophthalmological evaluations, and neuroimaging findings. To evaluate and compare visual function impairment, ophthalmological data were converted to a global visual function score, which took into account visual acuity, visual field evaluations, and laterality deficiencies. The visual acuity score was defined according to the International Classification of Diseases 10th Revision. Visual field deficiencies were converted to a score of 0-2. Two opposing groups were then distinguished according to the presence or absence of EOT. Visual acuity, visual field results, and global scores were compared between groups before and after treatment. RESULTS Twenty-six patients were included in the study: 17 patients with craniopharyngioma, 3 patients with pilocytic astrocytoma, 2 patients with ganglioglioma, 2 patients with germ cell tumor, 1 patient with macroprolactinoma, and 1 patient with Rathke's cleft cyst. There were 11 children in the group with edema and 15 children in the group without edema. None of the following criteria were statistically different between the 2 groups: age, sex, clinical symptoms at presentation (endocrine deficiency or intracranial hypertension signs), incidence of hydrocephalus, compression of the optic tracts and mass effect on the optic chiasm, tumor size and localization, presence of intratumoral cysts, treatment, type of tumor, or recurrence. The median global visual function and visual acuity scores were not significantly different between the groups either at presentation or at final evaluation. The visual field score was lower (i.e., more deficiency) in the group with edema than in the group without edema (p < 0.05); 89% of the patients with edema had severe or mild visual field impairment versus only 40% of the patients without edema. At the final examination after treatment, the visual field scores were not different between the 2 groups. Although not significant, the number of patients with optic disc pallor was greater in the group without edema both at diagnosis and at final examination. CONCLUSIONS This study confirms that EOT in the context of sellar region tumor in children is not necessarily associated with a less-favorable visual prognosis.