A circular wartlike nodule appears at the base of your horse’s ear. Maybe it’s just one, maybe it’s an entire cluster. Maybe your veterinarian has already removed it once and, guess what, it’s back! These common tumors—called sarcoids—are rarely more than cosmetic blemishes, but treating them is extremely challenging. There’s no one effective treatment that works very well.

Recently, however, veterinarians have explored the efficacy of autologous vaccination, in which the practitioner removes a sarcoid lesion from the horse and implants pieces of it back into the horse’s neck, with some success. David Levine, DVM, Dipl. ACVS, an assistant professor of Clinical Large Animal Surgery at the University of Pennsylvania School of Veterinary Medicine’s New Bolton Center, described the results of his practice’s experience with this method at the 2015 American Association of Equine Practitioners’ Convention, held Dec. 5-9 in Las Vegas.

Historically, said Levine, veterinarians have used many modalities to treat equine sarcoids, including:

  • Most commonly, surgical excision, with a 50-64% recurrence rate (a 36-50% success rate);
  • Cryotherapy (freezing), with a 60% success rate;
  • Interstitial brachytherapy (radiation), with anywhere from 50% to 100% success;
  • Chemotherapy (cisplatin), which researchers performed with 96% success in one study;
  • Imiquimod anti-tumor medication, which results in about 56% remission; and
  • Xxterra herbal paste, with a 56% response rate.

While some practitioners have dabbled in autologous vacci