Good question! "as" and "like" can be considered as synonyms, but in this example the difference in meaning is significant enough. "She lives AS a man in her body" - She feels like a/identifies as a man. "She lives LIKE a man in her body" - She may still feel like a female, but acts in the body like a man would.

"Sie lebt wie ein Mann in ihrem Körper." Als or wie, what is the difference?

Boyish girl i suppose ?