Development of a cavernous malformation of the brain.

We report the appearance of a cavernous malformation associated with a developmental venous anomaly in a young boy 3 years after radiation therapy for a posterior fossa medulloblastoma. The presence of a stenosis of the venous drainage of the anomaly led us to postulate that venous restrictive disease, induced by radiation therapy, resulted in increased venous pressure and caused the formation of the cavernous malformation.