I checked the 8.0" of Galaxy Tab 4 and there's only a couple of millimeter difference with the Tab E 8.0" except that the speakers are located different, but you can just cut a hole on that part. I highly suggest testing the case though just to be safe.
I did a quick Google search and found a case for Samsung Galaxy Tab E 8.0" on ebay.
Click here to go to that page. Hope that helps.