What are they?
Sarcoids are a very common type of skin tumour affecting male and female horses, ponies and donkeys. They affect all ages apart from young animals under about 2 years. Some animals appear to be genetically susceptible to developing sarcoids.
Where are they found?
Sarcoids are usually found on the skin of the head and neck, between the front legs and in the groin area, although they can appear anywhere on the body. Whilst they can spread within the skin, they do not spread to the internal body organs.
Types of sarcoid
There are about six different types of sarcoid which vary in appearance and growth patterns, from flat flaky patches to large, ulcerated pedunculated growths.
How do they spread ?
Sarcoids do not spread between animals but can be spread by flies in summer from one area of skin to another, usually when there is an open wound. For this reason it is important to protect wounds on animals that already have a sarcoid elsewhere on the body.
Sarcoids vary greatly in appearance, in some cases resembling warts, areas of proud flesh or even a patch of ringworm. To confirm a diagnosis of sarcoid, a tissue sample or biopsy can be taken and examined at the laboratory. However, sampling a sarcoid can stimulate it to grow, so they are often treated without taking a biopsy first and should always be treated promptly if a biopsy result confirms the presence of a sarcoid.
There are many treatment options available, depending on the type, location and size of the sarcoid, the temperament of the patient, the owner’s financial budget and the particular experience and preferences of the veterinary surgeon.
At CVP we treat sarcoids in a number of different ways, using a variety of topical chemical creams and drugs injected directly into the sarcoid (Chemotherapy), various surgical methods, including surgical removal and cryo-surgery. Cryo-surgery involves freezing the sarcoid tissue using liquid nitrogen spray, which has a temperature of -196°C.
The success rate for treating sarcoids is overall normally around 70 -75%, but any sarcoid can recur at the original site or new sarcoids can develop nearby or elsewhere on the skin.
In the past, many sarcoids that were small and inactive were left untreated and monitored for growth. It is now considered better to treat a sarcoid at the earliest opportunity to increase treatment success rates and reduce the chance of further sarcoids developing.
The 6 different categories of sarcoid
1) Verrucose – Usually irregular patches of slightly raised, crusty or flaky skin
2) Fibroblastic – Consist of red/yellow ulcerated, proliferating masses, that bleed readily and may be covered in a crusty discharge, attracting flies in the summer. They may become quite large and hang down from the body
3) Nodular – Usually smooth, firm, fibrous lumps within or under the skin. They can be found individually or in groups
4) Occult – A smooth, flat area of hair loss often with well-defined margins with relatively normal looking skin
5) Malignant – Widespread infiltration of different types of sarcoid covering a considerable area, with little evidence of normal skin, usually seen in genetically susceptible individuals
6) Mixed – These contain any combination of the different types of sarcoid, occurring at the same location at the same time
Cryo surgery – This can be carried out under sedation or under a short anaesthetic. The sarcoid and an area of visibly normal skin around the sarcoid are frozen with liquid nitrogen spray. The resultant scab is large and thick and usually separates over the next few weeks, leaving a raw wound that then heals like a normal wound.
Scalpel surgery – Cutting off a sarcoid is generally reserved for a very small number of cases, as it is very difficult to determine where the sarcoid “roots” end. Closure of the wound is difficult as a large area of tissue is often removed.
Rubber banding – A very cheap method of treating some sarcoids, rubber rings can be very effective as long as an area of normal skin is included within the area constricted by the rubber band.
BCG injections – A very effective means of treating certain sarcoids around the eye. A course of three BCG injections is usually given over a period of about a month. The sarcoid then gradually shrivels up and disappears over the following 2-3 months.
Topical chemotherapy – A number of creams are available to treat sarcoids. By far the most effective is developed and supplied by the University of Liverpool Sarcoid Department, the cream being called LUDES. Used only by a veterinary surgeon, LUDES cream is applied about five times over about a fortnight, causing considerable initial reaction. The sarcoid then dries up and the scab may take several months to fall off completely.