Skin is the largest organ of the mammalian body, and in the horse, it provides vast surface area for lumps and bumps to appear. Skin bumps come in all shapes, sizes, and colors…some hairy, some hairless, and they’re usually not painful when poked or prodded. Lumps and bumps may stem from a wide variety of causes such as inflammation, scar tissue, warts, or tumors. As a result, there are a lot of questions about whether to remove a bump or leave it be. Here’s how we like to think about this question at EquidDoc Veterinary Services:
Most skin bumps in horses are benign, meaning that they are unlikely to metastasize or spread, to other areas of the body. However, some skin tumors are locally aggressive meaning that they can suddenly grow and spread without notice. There is increasingly more medical evidence that the earlier a bump is removed, the less likely it is to grow back. In the past, because skin bumps are likely low risk for metastasis, a wait-and-see approach was taken. If this was the case today, we suggest cataloging photos of the bump(s) every 2-4 weeks and urge to call EquidDoc if growth is noted. However, additional factors may cause us to remove a bump even more urgently, for example, the location, appearance, and time of year.
It is important to remove a bump or lump that interferes with tack or your horse’s ability to eat, pass manure, or urinate comfortably. The look of the bump can also tell us a lot; does the bump look like it could be caused by a tumor that is locally aggressive such as a sarcoid, squamous cell carcinoma, or melanoma? Is the tumor in a location of the body that allows the surgery site to be wrapped after removal? If not, then wintertime is the ideal time of year to schedule removal, so you don’t have to worry about flies and other insects disrupting skin healing. The removal of some larger bumps will require your horse to have some time off from work, and that is also usually best accomplished in the winter!
Surgery may sound scary, but most surgical removals of skin bumps are a quick procedure, and most can happen on the farm! Your horse will be sedated so they standstill, the skin around the bump will be numbed, the bump will be removed, and the remaining skin will be stitched closed with one or two layers of sutures.
In addition to removing a bump while it is small, we also recommend getting a biopsy (microscopic laboratory analysis of the bump). This helps to identify what type of cells are present, if it is a tumor, and if all the mass was removed (aka clean margins). If a biopsy confirms a locally aggressive tumor type, then we will make recommendations to use a topical treatment following surgery to further kill off any remaining tumor cells. We may elect the use of cryotherapy with liquid nitrogen, injectable chemotherapy agents, or chemotherapy ointments to further help reduce the likelihood of the tumor returning.
If your horse has a lump or bumps that you’ve been questioning removal, contact your EquidDoc team to schedule an exam with your veterinarian to assess the situation and remove it if necessary! Call the office @ 508-885-4205 or email office@equiddocvet.com.