Choroid plexus papillomas have been reported in Aicardi syndrome. Management of these tumors is controversial because their natural progression in Aicardi syndrome has only been rarely documented. This report describes the progression of such a tumor over 7 years in a girl with Aicardi syndrome. A magnetic resonance imaging study at 2 months of age demonstrated a right ventricular mass that was consistent with a unilateral choroid plexus papilloma. The mass enlarged over the next 7 years without causing any clinically apparent symptoms, ventricular enlargement, hydrocephalus, or mass effect. The tumor was removed without change in behavior or development. The known cases of Aicardi syndrome associated with choroid plexus papillomas are reviewed. The heterogeneous nature of this lesion is highlighted.