Over the past 12 months Dave Kruger and the equine team have been working with the dedicated owner of a 15 year old standardbred mare with Sarcoids.
In late 2020 a 15 year old Standardbred mare presented with a large skin mass just under her right eye. Numerous smaller wart like lesions were present in the surrounding skin and above the upper eyelid.
The mass was present at the time the mare was purchased and a presumptive diagnosis of Equine Sarcoid was made. Over the months that followed the mass doubled in size.
WHAT ARE SARCOIDS
Sarcoids are a common skin tumour in equines that are associated with bovine papilloma virus. They can present in a variety of ways, including flat or wart like lesions. On occasion they can resemble “proud flesh”.
Whilst very rarely, some sarcoids will spontaneously resolve and heal, it’s most common that they continue to grow. Being benign, these tumours do not spread systemically but can grow to a point that they interfere with normal function depending on their location. In this case the mass was affecting this mare’s lower eyelid function.
Treatment of sarcoids is varied and can include surgical excision, cryotherapy (freezing) and various forms of chemotherapy, including injectable and topical. Treatment is not always successful and around half do not resolve and may continue to grow.
INTRALESIONAL INJECTION
After discussion with a specialist equine surgeon, Dave was advised that surgery with this horse was ruled out due the extent of eyelid involvement and the size of the mass. Instead, the Initial treatment involved intralesional injection of a mycobacterial cell wall extract. The rationale behind this therapy is that this product is a powerful immunostimulant.
Over the 6 weeks period that followed the intralesional injection, some reduction is size of the tumour was achieved.
Post injection progress pictured. While some reduction in size was achieved the healing process stopped.
AUTOLOGOUS VACCINATION
The healing progress stopped after some time and so the decision was made to attempt autologous vaccination.
Autologous vaccination is a technique where sections of the tumour are frozen in liquid nitrogen and then implanted subcutaneously. Because equine sarcoids have an association with a papilloma virus the reasoning behind this method is that the horse will develop antibodies to the virus and mount an immune response. This has been reported in the literature for sarcoids but is not routinely performed.
In the weeks following this procedure the sarcoid appeared to reduce further in size.
Implant site pictured
Following the autologous vaccination the sarcoid appeared to reduce further in size.
POST AUTOLOGOUS VACCINATION
Whilst the results were encouraging the site of tissue harvest never fully healed and the decision was made to attempt surgical “debulking”.
Under general anaesthetic the main mass of the largest tumour was surgically removed. The skin was closed as far as possible and a “Stent” bandage was place to protect the incision site.
Healing was uneventful and the owner is pleased with the results and currently the mare is comfortable and back in ridden work.
