# Incidentally Detected Colloid Cyst in a Pediatric Patient With Facio-Audio-Symphalangism Syndrome: A Case Report

## TL;DR

A 9-year-old girl with a rare genetic syndrome had a colloid cyst discovered during routine imaging, and it was successfully removed without complications.

## Contribution

This case report highlights the rare association between facio-audio-symphalangism syndrome and a pediatric colloid cyst.

## Key findings

- A colloid cyst was incidentally found in a neurologically stable pediatric patient with facio-audio-symphalangism syndrome.
- The cyst was successfully resected via a transcallosal approach with no complications and no recurrence at three-year follow-up.
- The patient had a heterozygous mutation in the NOG gene, suggesting a possible genetic link.

## Abstract

Colloid cysts are rare, benign intracranial lesions typically arising from the anterosuperior third ventricle. Although commonly diagnosed in adults, their occurrence in pediatric patients is uncommon and may follow a more aggressive clinical course, occasionally resulting in acute deterioration or sudden death. The association between colloid cysts and genetic syndromes remains poorly understood. We report the case of a nine-year-old girl with facio-audio-symphalangism syndrome in whom a third ventricular colloid cyst was incidentally discovered during routine surveillance imaging. The patient was neurologically stable and asymptomatic with no clinical features of raised intracranial pressure. Neuroimaging revealed a well-circumscribed lesion at the foramen of Monro with imaging characteristics consistent with a colloid cyst measuring 1.2 × 1.0 × 0.8 cm and mild ventricular enlargement. Genetic testing demonstrated a heterozygous mutation in the NOG gene. After multidisciplinary discussion and extensive counseling with the family regarding the risks of observation versus surgical intervention, elective resection was performed via a right interhemispheric transcallosal approach. Gross total resection was achieved without complications. At the three-year follow-up, the patient remained clinically stable with no radiological evidence of recurrence. Pediatric colloid cysts are rare, and their incidental discovery in asymptomatic children is particularly uncommon. The association with facio-audio-symphalangism syndrome in this case is unusual and could be associated with a possible genetic contribution. Given the uncertain natural history in children, individualized management and shared decision-making remain essential.