dr. william gahl is the program's lead investigator. >> the bottom line, the bone is not involved. not acro megaly. it's not just confined to the muscles. what could it be? >> this is an image of sally's brain. that's incredible. >> when the image was found that even the muscles that govern the movement of the eye, which are really smaug muscles, are huge. the neuroradiologist saw this and sort of the went wild over this. look at the size of these muscles. they're three or four times bigger. >> you've never seen anything quite like this. >> there's no way to make those muscles bigby moving your eyes a lot. why would they be that big? >> it's a clue. it suggests something inside the muscle itself. so the udp team took a sample. you took some muscle from her arm? >> right. and really this was one of those sort of judgment decisions because she had had a muscle biopsy one year before that was read as normal. so we weren't like 99% sure we should do this. we were like 70%, 80% sure. >> in five days the tests are complete. sally is sent home to north carolina but no diagnosis, not yet.

dr. william gahl leads a team of doctors. they are the best in the world. together, they focus their vast expertise to save patients lives. they are detectives in ter ch of clues to solve mysteries no other doctors could solve. >> you are talking about patients seen by some of the best in the country here. they are good clinicians and diagnostic doctors everywhere. you are taking the hardest, the most challenging cases of all. >> we expect a high failure rate. we expect a success rate of 10% or 15% or so. >> the program was launched two years ago at nih. it accepts the rarest of medical cases. itis not only about saving lives. they are hoping to discover new diseases and create new science. >> it's the inspiration we all have as clinical researchers. >> they have had more than 3,000 inquiries. more than 1,000 applications made it to dr. gahl's desk. they have accepted a little over 300 patients. >> you have to tell a lot of people no. >> we do, yes. >> it seems like that would be hard. >> it is hard. it's very hard. i have to take sol las in the fact we hav

dr. william gahl leads an elite team of doctors, specialists and researchers and they are the best in the world. together, they focus their vast expertise to try to save patient's lives. they are detectives in search of clues to solve mysteries no other doctors could solve. >> you're talking about patient who is have been seen by some of the best in the country here. they're very good clinicians and diagnostic doctors everywhere. so you're taking the hardest of the most challenging cases of all? >> we expect a failure. we expect a high failure rate. we expect a success rate of 10 or 15%. >> reporter: but 10 or 15% is a bright ray of hope for some patients. >> how much more you can do physically really speaks volumes? >> yeah. >> sally had all but given up. look at her back. it was as if muscle mass was consuming her body. sally was transforming into the incredible hulk. >> this is the mri of the brain. even the muscleless that govern thement of the eye, which are really small muscles are huge. the raidologyist saw that and went wild. it's three or four times bigger. >> they had probably n

dr. william gahl is the program's lead investigator. >> when you see these pictures, they are incredible. you think steroids? >> sure. we pretty much all thought it, except the letter said she's not taking steroids, she's not taking anything anabolic, and she did weight lift a little bit but many years before. so there's no possible effect of that. so the endocrinologist had eliminated all the things we naturally would think about. >> when she falls asleep she tightens up some. >> reporter: dr. gahl and the udp see only the rarest cases. >> there's still a fair amount of rigidity. >> not only do they want to save lives, but they also want to advance science by identifying new diseases. >> bottom line, bone's not involved. it's not acromegaly. just confined to the muscle. what in the world could this be? >> reporter: during a week of intense tests, there are scans, blood work, an examination of everything going on inside sally's body. >> so this is sally's mri of the brain. that's pretty incredible. >> when the images were found, it was seen that the muscles, even the muscles that govern t