To investigate the presentation, diagnostic delays, and outcomes of patients with tectal gliomas previously presumed to be congenital aqueduct stenosis.

Congenital aqueductal stenosis is a known idiopathic cause of hydrocephalus in children. Hydrocephalus can similarly be caused by tumoral obstruction, such as that seen with tectal gliomas. There have been only 2 cases, to our knowledge, of presumed congenital aqueductal stenosis that were in fact due to tectal gliomas (Afshari et al, 2022).

This was a retrospective review of patients presenting at our institution from 1989-2023 with midbrain gliomas. We identified patients with tectal gliomas on imaging and investigated for a history of congenital aqueductal stenosis. We collected information on initial presentation, treatments, features of gliomas, time to diagnosis, and change in the glioma over time.

Eighty-one patients were identified with midbrain glioma. Of them, 9 patients with presumed congenital aqueductal stenosis later found to be tectal gliomas were identified. The median age of aqueductal stenosis diagnosis was 7 months (ranging from prenatally to 17 years) and the median age of tectal mass diagnosis was 18 months (from 2 months to 17 years). The median time to tectal mass diagnosis was 3 months (from 1 to 36 months). All patients presented with symptoms of hydrocephalus and 7/9 were treated with a shunt (5/7 with endoscopic third ventriculostomy). Over the course of follow-up, 5/9 tectal masses grew, 2/9 were stable, and 2/9 were lost to follow-up. Four of nine were biopsied, revealing 3 low-grade gliomas and 1 high-grade glioma. Only one patient required further treatment with chemotherapy.

This study provides the largest group of patients with presumed congenital aqueductal stenosis later diagnosed as tectal gliomas. This study highlights tectal gliomas as an important consideration on the differential for children presenting with presumed congenital aqueductal stenosis.