Hello everyone. I had a blank screen in the iTunes store. In fact only the my music tab worked. Apple support tried very hard escalating this all the way up to the engineers with no solution. Reloaded the OS twice and did every possible suggestion from every forum. This all happened after El Capitan was installed. iTunes is connected to the OS and therefore is not a "separate" app. This morning frustrated and willing to try anything, i went to Apple.com and downloaded a new iTunes.dmg. It did an overwrite of the existing iTunes and BAM! it was fixed. Anyone experiencing this issue should try an overwrite of iTunes first. NOT the entire OS. This can save hours and days of trouble shooting and frustration. Hope this helps.
Dave