Perhaps root initials? These would be tightly attached to the plant and wouldn't be the cause of problems

I have them on my yellow pear tomato plant, and they're spreading all over, just like the sudden wilting branches....from another post, it sounds like I have a bacterial wilt that is rapidly killing my plant. I'm on my way to the garden right now to murder it in the interest of the greater good (i.e., my other healthy plants). I hope your tomato is not similarly afflicted--good luck!

It does sound like vestigial roots, but the sudden appearance along with wilting is a classic symptom of tomato pith necrosis. The way to confirm it is to split the affected stems open and look for hollow, brown centers.

It likes cool nights and high humidity, and is most likely soilborne.

The other possibility -- if the bumps have been there all along, and the wilting of one branch is the only new thing -- is something like a stem borer. Cut off the wilted stem several inches down from the wilt, or to a major branch, and if you want you can split that open to find the larva and kill it.

I'm assuming in both cases that "wilt" means sagging leaves, not yellowing.

--Alison