My coming out at work was a non-issue. Granted, I didn't need 6 weeks off at once, and worked around my schedule for my surgeries (hysto, top). But after I legally changed my name, I came out at work, and a month later they (management) made the announcement. It was a total non-issue.
I'm lucky, I know, but it may not be as big a deal as you think. Many have transitioned on the job and kept them.
For me, once I got past the hysto and name change, I couldn't tolerate female pronouns and the wrong name any longer, anyway, so it made coming out far easier (or the risk worth it).
Jay