A sarcoid is a benign tumour known as a fibrosarcoma. They can occur anywhere on the horse but are often on the ventral regions as it is believed they are spread from horse to horse by biting flies; so a fly feeds on a horse with a sarcoid and then bites another horse and transmits sarcoid cells to the new host. This hypothesis has been supported by the fact that male horse DNA can be found in female horse sarcoid tissue proving that cells have been transferred from another animal. Another theory is that sarcoids result from infection with bovine papilloma virus but other studies have failed to isolate this virus from equine sarcoid tissue. So the actual cause of sarcoids remains the subject of much debate, but if your horse has one or more sarcoids, what should you do???
Historically, sarcoids have been cut off, frozen with liquid nitrogen, various cytotoxic creams, particularly the “Liverpool” cream produced by Professor Derek Knottenbelt, have been applied and also autologous vaccines have been made from sarcoids in order to stimulate an immune response by the horse to attack sarcoid cells. The “Gold Standard”, particularly for periocular sarcoids, has been to treat the sarcoids with radioactive beads or wires, so a form of radiotherapy. Such treatment has to be done under strictly controlled conditions and is very expensive.
More recently, the use of surgical lasers has become the treatment of choice to remove sarcoids. Diode lasers have been most widely used but they cut slowly and the laser fibre needs constant attention to refresh it during the surgery. At Peasebrook, we have invested in a Carbon Dioxide laser which is much more powerful than the diodes and as you will see from the video below, cuts through the tissue effortlessly. It is essential to take a good margin around the sarcoid and to make sure that all cells in the subsequent crater are also treated. The noise in the video is generated by the smoke evacuation system which is necessary to prevent particles being breathed in by personnel. The wounds can be partially sutured close if required but are generally left to heal by secondary intention. Many lesions can be removed from the standing sedated horse, but if there are extensive sarcoids on the inner thighs, it is safer to do the surgery under general anaesthesia.
The Carbon Dioxide laser is also very efficient at removing facial sarcoids as it is very precise in it’s cutting ability and causes little damage to surrounding tissues. All personnel and the horse, wear protective glasses during the surgery to prevent damage to the eyes.
Sarcoids are a nuisance to the equine world, often causing problems during the vetting procedure. In most cases they can be dealt with and successfully removed, especially if this is done early. Once in a while we come across horses that appear to be immuno-incompetent and succumb to tumour cells, ending up with extensive lesions that reappear whatever treatment is instigated.