Todayโs path rounds are on ๐๐ช๐ฎ๐ข๐ง๐ ๐ฌ๐๐ซ๐๐จ๐ข๐๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ซ๐๐จ๐ข๐๐ฌ are the most commonly diagnosed tumour of horses! They occur in the skin, and generally are pretty harmless. There are 6 recognized types, ranging from a hairless patch of skin to large, aggressive masses.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Any age, breed or sex of horse can get these!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Interestingly, these masses are believed to be caused by ๐๐จ๐ฏ๐ข๐ง๐ ๐ฉ๐๐ฉ๐ข๐ฅ๐ฅ๐จ๐ฆ๐๐ฏ๐ข๐ซ๐ฎ๐ฌ! Yes, you read that right, a cow virus causing a tumour in horses. Wild! There is a lot of evidence to suggest that the virus is spread to horses by flies landing on scrapes, cuts or other wounds, thus introducing the virus into the horseโs system.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
As mentioned, these tumours generally donโt cause an issue as they are considered relatively benign. It is also extremely rare for them to ๐ฆ๐๐ญ๐๐ฌ๐ญ๐๐ฌ๐ข๐ณ๐ (spread to distant sites), unlike some other tumour types. However, sometimes they can become quite large and ๐ฎ๐ฅ๐๐๐ซ๐๐ญ๐๐ (bleeding from the surface), and potentially interfere with the horseโs day-to-day activities.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Often these tumours are diagnosed just by looking at them. Normally, a ๐๐ข๐จ๐ฉ๐ฌ๐ฒ (looking at tissue under a microscope) would be the best method of diagnosis, similar to other tumours. However, these tumours are known to become more aggressive after being disturbed, often expanding in size uncontrollably after being damaged. So often veterinarians are quite cautious about angering these tumours, even though they are technically benign.
If a biopsy is done, the biopsy will show long extensions of the ๐๐ฉ๐ข๐๐๐ซ๐ฆ๐ข๐ฌ (outer layer of the skin) down into the deeper layers of the skin. Super neat!
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
If the sarcoid is in a location that does not bother the horse, sometimes these tumours are โtreatedโ with ๐๐๐ง๐ข๐ ๐ง ๐ง๐๐ ๐ฅ๐๐๐ญ, otherwise known as doing nothing. However, if they are bothering the horse, or the owner, there are a variety of treatments that can be tried.
Surgical excision is the most obvious one, where the tumour is simply removed. However, there have also been promising results with ๐๐ซ๐ฒ๐จ๐ญ๐ก๐๐ซ๐๐ฉ๐ฒ (freezing the tumour with liquid nitrogen), antiviral drugs to kill the virus, or even local ๐๐ก๐๐ฆ๐จ๐ญ๐ก๐๐ซ๐๐ฉ๐ฒ (applying chemicals that kill cells). It is important to note that treated sarcoids tend to come back, and may even be more aggressive upon their return! So a discussion with your veterinarian regarding the pros and cons of treatment is key.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-7) Various types of sarcoids in different locations. See how they can range from flat, hairless areas to huge masses?
8 ) An example of what a pathologist would see under a microscope! Those long bright pink strands extending into the tissue are a hallmark sign of sarcoids.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Villalobos, AE. Equine sarcoids. Merck Veterinary Manual, 2014.
Photos 2-8 ยฉ Noahโs Arkive contributors Giles, Jakowski, Wright, Eastep, Ward, Wallace licensed under CC BY-SA 4.0.
