An introduction to sarcoids in the horse ...
[also read or post to our sarcoid forum]
Equine Sarcoid Frequently Asked Questions
- What causes Sarcoids?
- Are there different types of
Sarcoid?
- How common are Sarcoids?
- What treatments are available?
- Are Sarcoids contagious?
- Are Sarcoids being researched?
- What is the prognosis for a horse with
Sarcoids?
A Sarcoid is a tumour involving connective tissue {ie. muscle,
sub-cutaneos tissue, etc.}. A tumour which may appear outwardly
similar is the Lymphoma {cutaneous lymphosarcoma}, which involves the
Lymphatic system {glandular system to you or I}. Both these tumours
are distinct from epithelial tumours {carcinomas & melanomas}.
The sarcoid begins as a small wart-like growth, but may progress,
through stages of rapid growth, to be the size of a tennis ball.
Generally being dry scaly masses that may ulcerate & bleed, the
main problems with a true sarcoid are those of secondary infection
& physical interference e.g. with tack. The key difference
between sarcoids & lymphomas is that sarcoids are benign,
lymphomas are malignant. Sarcoids exist in several forms, see below
for details.
Sarcoids are believed to be caused by a virus, though I have
failed to find a detailed explanation from any source. It has also
been shown that Sarcoids occur more often in the older horse & on
sites of previous trauma. See below for notes on contagion. From my
own experience I noted that sarcoid growth appeared most in spring
& early summer; obviously there are many factors that could
precipitate this: dietary change, increased UV light, fly strike,
changing routine / stress levels to name but a few. I was unable to
conclude which factor(s) was the cause.
Yes, Sarcoids can be split into several types ....
VERRUCOUS SARCOIDS
Typically these are dry golf ball size lumps, though size may
vary considerably.
They most often occur on head, chest & shoulder/
under-leg. Normally lacking hair,
they are not difficult to spot.
FIBROBLASTIC SARCOIDS
If a verrucous sarcoid grows & splits or is otherwise
physically damage then it may progress to this type. This is the
type that tends to cause more problems as it grows & bleeds;
some have been known to reach the size of a small football.
Ulceration, fly-strike & secondary infection can all be issues
to be tackled. Growth rates do vary with these sarcoids sometimes
lying dormant for several years.
OCCULT SARCOIDS
These are a flat form of sarcoid which again may become the
fibroblastic type if damaged.
NON SARCOIDS
As previously mentioned, sarcoids can be confused with other
growths. Identification is important since many of the other
growths are malignant and could therefore spread internally.
Biopsy by an expert is the most accurate form of diagnosis, but
this has its drawbacks see under "Treatments".
Sarcoids are relatively common particularly in older horses,
though severe cases are considerably less common. Fortunately the
more serious cutaneous lymphosarcoma is relatively uncommon.
Various different treatments are available ...
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Traditional Surgery
Physical removal of the tumour
has been the normal practice. However there are multiple
drawbacks to this technique.
1] A high percentage of cases recur within several
years.
2] Growth can be accelerated by the physical trauma of the
surgery.
3] Possibility of "seeding" the tumour elsewhere by cell
debris. esp. if diagnosis is incorrect & tumour is
malignant.
4] Possibility of significant scarring or physical
disability due to site of tumour operation.
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Cryosurgery
This is a technique whereby the
area to undergo surgery is repeatedly fast frozen to destroy
all tissue before surgical removal. This decreases the
likelihood of recurrence & seeding. However the
technique is not suitable for use near sensitive tissues
such as the eyes.
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Radiation Therapy
This technique is similar to that
used to treat human cancer patients; the affected area is
irradiated using a localised source. The drawbacks of this
treatment are :
1] Localised side effects of radiation
2] Requirement for specially trained staff to administer
treatment.
However the treatment may be particularly suitable around
the eyes, where surgery is impossible.
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Immunotherapy - eg. Human B.C.G. Vaccine
A technique to activate the
horse's own immune system against the tumour cells. Two
different methods can be used:
1] Injection of BCG
vaccine - Multiple injections
into the tumour over a period of some weeks.
2] Introduction of Sarcoid
tissue - Deactivated Sarcoid
cells introduced under skin to build immune system over
several months.
These treatments are only suitable for small tumours &
do take sometime to work, however they do have the advantage
of being relatively non invasive.
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Chemotherapy - eg.Liverpool Cream, Cisplatin
Again a technique originally
developed to treat human cancer patients. A variety of
chemical agents are being studied, the main characteristics
being:
1] Application is topical or injected into tumour - this
minimises the systemic effects of the toxins on the
patient.
2] Typically the chemical agents are toxic heavy metal
compounds in an inert carrier base.
3] A dosage balance must be struck between tumour
irradication & toxic side effects.
4] Beneficial where surgery is impractical or in conjunction
with surgical techniques
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Other Techniques & remedies
A list of misc. other treatments
that I am aware of. Thankyou to all who have emailed me with
their experiences.
1] Laser
Vapourisation - Use of a hot
laser to destroy tumour tissue, typically in conjunction
with surgery.
2] Constriction - Application of a band such as a castration ring
to remove "hanging" tumours. cf. traditional wart
removal.
3] Tea Tree Oil - Applied topically has apparently been of help
in some cases.
4] Thuja - Can be given orally as tablets or applied
topically as an oil. Thuja is a Chinese herbal remedy that
is sometimes available from natural health stores. I have
one report of some success with this, on sarcoids that were
not responding to traditional treatments; thankyou Michelle.
If anybody else has used it please let me know.
5] Hyperthermia (Heat
Treatment) - localised intense
heating of tumour cells using a special instrument. Thanks
Holly for this & the next.
6] Dermex - A herbal paste made from a plant grown in
Wyoming, USA. (Don't know what the plant is, please let me
know if you do). Applied topically, has been successful on
an awkward occult sarcoid. Also useful for reducing
fibrblastic size before other treatments.
7] Colloidal Silver Spray or aqueous - applied topically on a daily basis.
8] Indian Mud Applied topically to 'burn' away the sarcoid.
9] Raw Honey Applied topically, twice daily for 2 to 3 months.
10] Hilton Ditton Herbs Used in feed as an oral immune booster. This appears quite
popular and can be used along with other treatments.
11] Actimune Another oral immune booster.
12] Colostrum Used as an oral immune booster. I'm interested to hear from
anybody using this. What colostrum are you using? Since most animals lose
the ability to absorb colostrum antibodies at only a few days of age,
do you feel that colostrum is boosting the immune system more than
simply feeding milk powder?.
Author's Comment, "Seems to me
that someone needs to research what the active substances in
Tea Tree, Thuja, Dermex, etc are. If you're a Vet. Researcher,
why not spend some time on this?"
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Sarcoids are not considered contagious, however they may be spread
by contamination with living tumour cells. In other words any
mechanism that might scrape cells off the tumour & then place
them back in another site, could lead to the formation of a new
tumour. As previously mentioned, physical trauma to a sarcoid may
accelerate the tumour activity.
Yes, there is considerable effort being made to research into
these tumours. Some of the establishments are listed below:
Leahurst Veterinary College, Liverpool University, UK
Equine Research Centre, Newmarket & Cambridge University, UK
University of California, USA
This depends upon the severity of Sarcoid occurrence. Often small
Sarcoids will remain relatively unobtrusive & cause few problems
for a horse. On the other hand severe cases that resist treatment may
require that the horse be destroyed on humane grounds. Research is
continually improving the success rate of treatment; this combined
with the fact that Sarcoids are benign tumours, means that in the
majority of cases there is little risk to the horse's long term well
being.
This section includes a list of suggestions that are either not
covered elsewhere or that require emphasis:
1] Make regular inspections of any abnormal lumps & bumps
on your horse.
2] If you discover an abnormality, don't panic, keep a record
of any changes, this will help your vet.
3] Identification is critical, make every effort to have a
positive ID of the tumour type before making any treatment decisions.
cf. Risk of aggravation from biopsy.
4] If a Sarcoid is identified consider whether or not it
requires treatment. These tumours may not concern your horse if left
alone, yet can become problematical after interference.
5] If treatment is necessary discuss the various options and
their drawbacks. Not all vets are aware of the full facts, discussing
things with your vet can only be helpful to you both.
6] Try to minimise any external aggravation of the tumour - I
found that a mixture of Gammexane cream & sunblock lotion helped
to reduce summer problems without irritating the Sarcoid tissue.
7] If you don't succeed at first, try again. Keep in touch
with research developments, if your horse doesn't respond to one
treatment, consider a different one.
99] GOOD LUCK!
I have created this FAQ with the intent of helping others to
understand a little about the problems of Equine Sarcoids. It is
dedicated to Flare, my 15-3HH Thoroughbred Mare who lost her 6 year
fight with Sarcoids & Lymphomas, in the summer of 1995. Below I
will briefly describe the progress of her condition:
1] First noted a blemish under her front right leg. Over a
period of 6 months this developed to golf ball size with several
other small lesions near its base.
2] After 12 months surgery became necessary due to chafing
& subsequent bleeding during exercise. Also several small
blemishes had appeared on hind legs near mammary glands.
3] Traditional Surgery discovered further tumours nested under
visible ones. A total of 20 or so "Sarcoid" tumours were removed.
4] Surgery followed up with Laser Vapourisation
techniques.
5] 12 months without sarcoids, 1st 3 months spent recovering
from surgery.
6] After 1 year recurrence of Sarcoids noted, initial
development relatively fast, also more widespread.
7] 2nd Veterinary opinion suggests that Lymphomas are involved
as well as Sarcoids. Options: A] Cryosurgery but high risk of
increasing internal malignancy of Lymphomas or B] allow mare to enjoy
life as long as possible & hope for research breakthrough.
8] Option B chosen, Constriction used to control faster
progressing tumours. However, ulceration hampers attempts to do
this.
9] A further year or so passes, daily topical treatment to
avoid secondary infection has been continual but Flare seems quite
happy until recently.
10] Leahurst undertaking trials of Topical Chemotherapy
treatment and having considerable success. Flare spends 1 year
undergoing trial Chemotherapy.
11] Flare's tumours have decreased slightly after 1 year of
sporadic chemotherapy, but her body cannot withstand anymore therapy
due to the chemical toxicity. I should point out that during the
year I watched as many Sarcoid cases were cleared up using the
Chemotherapy, however Flare's case was the most resistant one
encountered.
12] I decide that Flare should be allowed to live out her life
running free in the paddocks of my home in Wales. She spends a happy
9 months before I have to have her put down due to her deteriorating
condition. She is sorely missed.
Other Resources
Read our Sarcoid Forum
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