Atypical syncope in a child due to a colloid cyst of the third ventricle.

A 10-year-old girl presented to an emergency room with acute-onset, brief, repetitive episodes of loss of consciousness. Computed tomography indicated a 0.6 cm colloid cyst of the anterior third ventricle, adjacent to the foramen of Monro. This finding was confirmed by magnetic resonance imaging. The patient underwent transcallosal surgical resection of the cyst without major complications or neurologic sequelae, and remains symptom-free after more than 18 months. Syncope is quite common in children. In contrast, colloid cysts are relatively uncommon in children, with only 100 cases reported in the literature. Colloid cysts are a known cause of sudden death. The possibility of colloid cyst should be considered in the differential diagnosis of syncope that presents in an atypical fashion, and such cases warrant emergent evaluation via neuroimaging.