"Draft cases are your 'work in progress'. When you first create a case, you may not have the time to finish it off (see case publishing guidelines) and may wish to keep in 'draft mode' for some time."
"You can keep cases in draft mode as long as you like. All users have up to 10 draft cases at any one time. If you need more than 10 draft cases, you can become a Radiopaedia.org supporter; additional draft cases are one of the many perks."