What is this large white patch on my purple tang. Help

[Yeos87]

My purple tang has this one large patch on the bottom of its stomach. I don’t think is ich as I previously had it in the past. This one is different, the spot is quite large and it has a white color to it. Anyone know what it can be, here are some picture. Thanks.

 

[nereefpat]

Lymphocystis would be something to look into. It's a viral disease that usually goes away on its own and not an issue. I can't really tell much from the pics, sorry. Pictures of fast swimming fish is difficult.