SAN FRANCISCO — The San Francisco Giants fan who suffered severe brain damage after he was beaten outside Dodger Stadium underwent emergency surgery this week after suffering another seizure, his family said.

Bryan Stow's family said on their website Tuesday that doctors at San Francisco General Hospital performed the surgery Monday after fluid built up in Stow's head and caused a 30-second seizure. The family said Stow's physician removed a bone flap that was put in Friday and "found some sort of growth he had never seen before."

The growth was removed and a filter was inserted to help drain the fluid from his head, the family said.

About $225,000 is being offered for information leading to arrests.