Good evening, Fiona, and thanks for the question.
There are various types of sarcoid tumors, and all sarcoids are a relative of the wart family. I have treated many sarcoids in my career using various methods, and in my experience have yet to encounter a “non-aggressive” tumor. Some can remain dormant, without signs of spreading or enlarging for years, but they can become reactive, usually due to some type of irritation or stimulation. Also, the sarcoid cells are carried through the bloodstream, and can (and do!) show up anywhere on the body.
The tumor on Samson may have been there for some time, and he may be lucky enough to not have it stimulated to grow, but that does not mean that some others couldn’t form elsewhere. There is really no guarantee either way, but in most instances in the horses I have worked with, it’s only a matter of time before a tumor or more start appearing.
As far as cost of removal; if they are removed when they first appear, it is relatively inexpensive, depending on your Vet and the method used for removal. Yet, if they are allowed to get large, they can cause severe problems as far as infection, abscesses, etc., and the expense can get quite high, while the success rate gets lower.
So…if you really want Sampson, I’d go for it and just keep a close eye for other tumors and have them removed immediately, before they become a problem and an expense. Hope this helps to make things a bit more clearer for you!
Please let me know if you have any further questions.
All the best,
-Dan C., DVM.