Equine Sarcoids
Sarcoids (or angleberries) are the most common tumours of horses
and a viral cause is suspected. They are locally invasive tumours of the skin, which
can remain small and dormant for many years before undergoing change
and rapid growth. Most horses (>84%) will have many lesions as opposed
to solitary sarcoid. Sarcoids do not metastasise. Sarcoids can occur
in horses, donkeys and mule, and most commonly seen in animals between
1 and 4 years of age.
Some parts of the body are more susceptible than others. These include
the eyelids, limb and the underside of the body and in male animals
inside the sheath and on the penis. Site and position of sarcoids is
very important for performance and as such lesions in the eyelid and
girth region can be very irritating and cause problems with tack.
Sarcoids can develop along blood lines although there are no noted breed,
age, sex or coat colour predispositions. Arabs have been showed to be more predisposed to sarcoids than other breeds.
There are 6 types of sarcoids:
- Occult Sarcoids:
Area of slightly thickened skin with a roughened surface, often hairless
and very slow growing. Interference with these sarcoids can lead
to a period of rapid growth.
- Verrucous (warty) Sarcoids:
Dry, horny and cauliflower-like, these arehairless and can have either
a broad base or a stalk.
- Fibroblastic Sarcoids:
This type can look like proud flesh. It can be firm and nodular and
its surface may be ulcerated.
- Mixed Sarcoids:
This is a mix between Fibroblastic and Warty sarcoids.
- Nodular Sarcoids:
This type is entirely under the skin and is found in areas
where the skin is thin, such as the eyelids
- Malignant Sarcoids
These are extremely aggresive & abrasive
.
Treatment:
There are 4 main ways of treating sarcoids. However it should be remembered
that they can be troublesome to treat and can increase in size and
number after any interference. Therefore during treatment care must
be taken to look for new sarcoids developing. The choice of treatment
depends on site and type of sarcoid.
- Surgery:
Good selection of cases is required as success is low. Ligating pedunculated
sarcoids with rubber bands is effective but they tend to recur.
Laser excision is a better option however restricted by cost and
practicality.
- Cryosurgery:
Again case selection important as results can be poor.
- Immune-Mediated Therapy:
Good results have been noted by a course of injections of BCG vaccine
into lesions, particularly around the eye.
Topical treatment using chemotherapeutic cream can be very effective
though care must be taken to prevent local tissue reactions. This
cream and other treatments can be injected into the sarcoid to improve
results, if necessary. Immune boosting treatments including interferon
are being used experimentally.
- Radiation
Radioactive sources can be inserted into small tumours and high success
rates are achieved, however cost and practically are limiting factors.
This is currently only available at one site in the UK and there
is a large waiting list for it.
- Do Nothing
Solitary or a small number
of sarcoids that do not cause interference can be left and
they may resolve themselves.
Sarcoids can be small innocuous lesions however they should
never be underestimated and treatment not undertaken lightly. |
