Mark Snow re-used practically an entire cue from "The X-files" in a TV movie called "Caroline at Midnight". It was of course orchestrated differently. It's one of those blatant lifts that smacks you in the face.
Maybe it was the other way around. I don't recall the name of the episode. Still a wonderful theme; the X-Files version is better.
Akira Ifukube also repurposed swaths of music in different films. As I recall, he was quite open about this -- feeling that one danger or marching or monster or "mysterious" theme if done well would be quite flexible enough to serve multiple films. Sometimes reorchestrated, sometimes not.
He also frequently reworked passages from his "classical" repertoire for films, and sometimes vice versa.
