Diffuse leptomeningeal seeding from benign choroid plexus papilloma.

Choroid plexus papillomas (CPP) are rare intracranial tumours with a favourable long-term outcome after surgical excision. Although they are histologically benign, local recurrences may occasionally occur, but leptomeningeal dissemination is exceptional. We report an unusual example of a fourth ventricle choroid plexus papilloma with diffuse leptomeningeal seeding. Neither the initial tumour nor the recurrence showed malignant histological features. Treatment with systemic and intrathecal chemotherapy was ineffective in this patient. We review the literature concerning leptomeningeal dissemination of benign choroid plexus papillomas.