Sarcoids, of which there are 6 different types, are the most common form of equine skin tumour. They are classed as low-grade fibrosarcomas (tumours).
They represent about 90% of the skin tumours seen in horses worldwide and have caused heartache for horses and their owners for centuries. Although common, sarcoids vary greatly in their size and appearance, the nature in which they grow and potentially spread and also the way they respond to treatment.
It is this variability that makes sarcoids such a challenge for owners and vets to manage and treat. It is thought that greater than 80% of horses with sarcoids have more than one. Certain breeds are more likely to develop sarcoids than others with thoroughbred’s accounting for a large number of the horses affected.
The vast majority of cases arise between the ages of 3 and 6 years of age although growth in later years does occur. It is thought that flies may play a role in the transmission and spread of sarcoids from horse to horse.
Not all types of sarcoid are easily recognised from a cursory examination thus some may be missed. Diagnosis is sometimes very difficult and may require microscopic examination to confirm the true nature of some types.
Key Facts
- Sarcoids are very common.
- Geldings appear more frequently affected.
- All equid species are susceptible, even donkeys and zebras
- Although sarcoids are a type of tumour, they do not spread internally.
- The tumours can arise at any cutaneous (skin) site but there are some sites more prone to occurrence: chest, groin, sheath, belly and axillae, around the face (especially around the eyes and mouth) and at sites of previous wounds.
- Sarcoids have a high chance of recurring even after certain treatments