Welcome! My name isXXXXX am a UC Davis graduate, and currently, a Medical Director of a veterinary hospital.
I am sorry to hear about this concern.
If it has been definitively diagnosed as a histiocytoma, many vets will do nothing with them. Over a period of 1-3 months, they can often spontaneously regress and disappear. Histiocytoma
Often, vets do literally nothing. Not even a topical medication.
Unless it is in an area that is getting injured like an elbow hitting the ground, or its getting infected because a dog is chewing/licking
it, surgery may not be indicated.
Another condition that would warrant surgery is if it is growing quite large, and it is in an area where it could be difficult to remove like by an eye
Otherwise, generally, waiting for about 3-5 months.
Please let me know if there is anything I did not cover for you. I hope that information has been helpful.
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