If you have let say a case report that you wish to have published and you submit your paper to a surgical related journal. Do you have to add histology slides?
I think, yes it's very necessary, because your histological work will be valuable by histological sections, however, the non-histological journals you want to submit your work, of course, will send to the histological reviewer.
If your publication is about cases diagnosed mainly by the histopathological features it is good to include pictures of histopatholoy. Pathologists also go through your paper just like the other specialists.