Body & HealthFact
The liver is the only organ that grows back.
Remove a large part of the liver and the rest grows back to the original mass. On paper about 10 percent of the starting tissue is enough, and in otherwise healthy people the liver can regrow roughly half its mass in around 30 days. It restores size, not shape.
Useful: That's why living liver donation works at all: both halves regrow.
Source: en.wikipedia.org