is it just me, or does the hollow look an awful lot like ichigo's hollow mask?
I'm glad that I'm not the only one who noticed. There is definitely a link between this hollow and Ichigo.
This is only a guess, but that might have something to do with Masaki. If you look at chapter 528 on page 16, you'll see a wound on Masaki's left shoulder. That wound was probably caused by this hollow.
Ginjo once said that fullbringers are born from having a parent attacked by a hollow. What if the reiatsu from this hollow went to Ichigo whilst he was still in his mothers' womb? That might have caused the changed in Ichigo's hollow appearance.
The flaw to this logic is that Masaki's quincy spirit energy would reject the hollows spirit energy. (Probably why no other quincy has fullbring powers) But, this case might be different because this hollow is an experiment of Aizen's. With it being an inperfect arrancar, it would have shinigami reiatsu also. Which might have been able to be transferred to Ichigo when Masaki was pregnant with him.