Page 893 - The Veterinary Care of the Horse

• The drug cisplatin is sometimes injected into small nodular and fibroblastic sarcoids.

Repeat injections are often required.
VetBooks.ir • The human BCG vaccine may be injected into nodular or fibroblastic sarcoids close to

the eye. This is repeated 1 week later, then 2 weeks later and again after a further 3
weeks. The injection interval is extended by a week each time until the lesion regresses.

The aim is to stimulate the immune system of the horse to reject the tumour tissue. A
drawback of this treatment is the risk of the horse developing anaphylactic shock as a
result of the foreign proteins. Thus the patient should be carefully monitored for 12–14

hours following each treatment. To reduce the risk of anaphylactic shock, the horse is
usually premedicated with a combination of flunixin, a cortiosteroid and an antihistamine

before the tumour is injected. Some swelling occurs following the injection. At the time
of writing the BCG vaccine is not available in the UK.

SURGICAL EXCISION

Surgical removal of small, discrete tumours with a wide margin of healthy skin can be
successful. However, there is quite a high rate of recurrence at a variable time (months to

years) afterwards. Wound breakdown sometimes occurs following surgical excision.
Incomplete removal of a tumour may cause it to grow rapidly and become even more of a

problem. Laser surgery has a higher success rate but is not suitable for sarcoids of all types
and locations and is not universally available.

APPLICATION OF AN ELASTIC BAND OR LIGATURE

Single tumours that have a narrow base may be ‘tied off’ using a tight, nylon ligature or
special elastic band. The blood supply is cut off and after some initial swelling at the site, the
tumour usually drops off 2–3 weeks later. Recurrence is common.

CRYOSURGERY

This involves removing the bulk of the tumour(s) surgically and freezing any remaining
tissue. It is then allowed to thaw and the procedure is repeated twice more. This is carried out

under sedation with local anaesthetic or general anaesthesia. It can be successful but again
there is a high recurrence rate afterwards. Cryosurgery is not suitable for tumours close to the

eye or over joints owing to the risk of damage to these structures.

VACCINATION

Vaccination against sarcoids is not currently available but may be in the future.