Herbicide damage.

If none used anywhere in the vicinity, then possibly herbicide-carryover which could be any kind organic matter, even commercially packaged..

See http://whatcom.wsu.edu/ag/aminopyralid/ 

And do the bio-assay which is linked at the left menu.

I have one tomato plant that looks exactly the same as yours does. I live in a condo and remembered getting a notice weeks ago that the landscapers were going to be spraying the lawns for weed control, so for my plant, I think the damage was definitely from herbicide. The bottom half of the plant looked normal and the top half looked exactly like yours with severely curled/folded stunted leaves. After weeks of having hundreds of flowers and no new tomatoes setting and no new growth on the plant, I finally lopped off the top half of my Husky Cherry tomato plant, removing all of the severely deformed curled/folded leaves. Within a few days of chopping off the top half of the plant, that looks like it was affected herbicide, all of a sudden the plant started setting new tomatoes and I went from having 18 cherry tomatoes to 30. I don't see any new flowers yet, but I see a few new suckers growing. I'm guessing the plant is now able to put all of it's energy into setting fruit into wasting it on the damaged top half of the plant that wasn't doing anything. I'm anxious to see if the new branches will have normal leaves or if they'll be deformed. Pam