Can there be a star larger in size than a galaxy?

The smallest galaxy to have ever been discovered is Segue 2, with an approximate diameter of 220 LY or 13,913,037 AU. The largest star we know of today is VY Canis Majoris, in the Canis Major Constellation. The star is 6-10 AU in diameter. 
However, there are the Dark Stars that formed in the beginning of our Universe (all of them burned out billions of years ago). These were probably the largest stars to have ever existed in the entire Cosmos. Their diameter could have reached (in theory) almost 2000 AU, as in 0,031 Light Years. The smallest galaxy ever discovered, Segue 2, has an approximate diameter of 220 LY or 13,913,037 AU, much much larger than the largest stars to have ever formed at the beginning of the Universe. 
PS: Dark Stars are not some black gigantic objects from a SCi-Fi movie. Dark Stars used to look very similar to regular stars, but instead of gas (like hydrogen and helium) they used to also contain a large amount of dark matter (or neutralino dark matter), the reaction between the dark matter particles would be the one that generated the largest amount of energy. I will write a post about Dark Stars in the near future. – Roman Alexander