The authors describe the case of a child who presented with hydrocephalus and phenotypic features characteristic of a multiple congenital anomalies/mental retardation syndrome. Dysmorphic facies, medial plantar lipomatosis, and developmental delay were observed in this case and are identical to documented findings of Pierpont syndrome diagnosed in 3 boys. This is the fourth case reported to date and is the first documented case of an oncological process- an intraventricular atypical choroid plexus papilloma tumor-found in association with Pierpont syndrome. Syndromes associated with choroid plexus papilloma are reviewed.