@croydon - It's a bad idea to think of the procedure where they remove your spleen as being trivial. People can and do die from the lack of a spleen, particularly if they take its functions for granted.
Of course, if all you had was a moderate splenomegaly, you were probably not in any danger of losing it.
Doctors try to keep a little bit of spleen in place now if they can, just because there is no real replacement for it. And if you do have it removed, you need to take medications to ensure that your immune system continues to work properly.
It might never affect you, but if it did, you could quickly be in serious trouble. So it's better to be safe than sorry.
In fact, for some people, the doctors pretty much just make them take antibiotics for years in order to make sure they will be OK without a spleen.