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

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 <i>NOG</i> 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.