Same issue here, on an iPad 3 WiFi.
Contacted support by email, this is the response :
Lauren here from the iTunes Store. I see that your iPad shows you have three app updates but when you open the app store, no updates are listed. I can certainly understand how you would like to get this sorted out so you update your apps and I would be more than happy to help you out with this today.
I have looked into this for you and I suggest restarting your iPad. I also located a particular thread from the Apple Discussion forums that contains information specific to your problem:
https://discussions.apple.com/thread/4744059?start=0&tstart=0
THis was on July 26, at 15:16. Wrote them back that none of the suggestions worked, no response!
this is lame on Apple's side. We spent a lot of money to buy their products, and that's what we get?
at least an acknowledge that there is a problem or SOMETHING.