Should I worry?

I would have them checked out. You could never be to sure. But I hope and pray none of them are cancerous.

I had a dog that developed them when she got older,, the vet said they were fatty tumors,,,,   humans get them too.   But I'm sure someone will come along this today and give you more information or ideas.

We have a Whippet. ((greyhound-like.))
 Its not the species, its more the age. Our old doggie (14) has non-cancerous cycts & fatty cysts. The only time they are worriesome is when they grow near the throat, which is where one of our dogs has grown. If the dog is young and healthy enough, and the cysts are in an area where they will interfere later with breathing and organ functions, Id suggest (as I hope would a vet) to remove them. If not, just leave them. When the dog has a check up, be sure to mention the cycst and have them looked at though, or if different types develope, have them seen.
 
There are four basic types of cysts and they all llok very different. maybe you can get a brochure with pictures from your vet so you know what your looking at.
Could also be calcium in the groin are of a female dog too. We had those too.
We've had everything I think