Progression of choroid plexus papilloma.

Choroid plexus papillomas are rare neoplasms that arise from choroid plexus epithelium. The World Health Organization classification describes three histological grades. Grade I is choroid plexus papilloma, grade II is atypical choroid plexus papilloma and grade III is choroid plexus carcinoma. Progression between grades is rare but documented. We present two adult cases, a 53-year-old female and a 70-year-old male, who demonstrated clear interval histological progression from grade I choroid plexus papilloma to higher grades.