How can I force Thunderbird to re-download a corrupted message from the IMAP server?

I have a mail message that is corrupted in Thunderbird, but correct on the IMAP server (which is Gmail). Is it possible for me to tell Thunderbird to discard its copy and re-download it from the server?

In Thunderbird, right-click on the IMAP folder in question and select "Properties". Under "General Information", click the "Repair Folder" button. This may repair the issue with the corrupted message, though I don't have corrupted messages to try it with. YMMV.

Justin Pearce's solution did not work for me. However, I found out that moving the e-mail from one IMAP folder to another and back worked and let me download/use the corrupted attachment.