CPD Article | EQUINE
Sarcoids
Contributor(s): Prof Derek Knottenbelt, Rosanna Marsella, Sue Paterson, David Senter, Vetstream Ltd, Anna Hollis
Introduction
• The most common cutaneous tumor, and probably
the most common tumor overall of the horse.
• 'Locally aggressive, fibroblastic tumor of equine
skin with a variable epithelial component and a
high tendency to recurrence' (Jackson, 1936).
• Significant cause of loss of commercial value.
• Probably the most common cutaneous reason for
euthanasia, although the condition is seldom fatal
in its own right.
• Cause: unknown although there is strong
evidence for the involvement of bovine papilloma
virus (BPV-1/BPV-2). There is certainly a genetic
component to the disease, with some horses
having a known genetic predisposition and a
known heritability index for some breeds.
• Signs: clinical signs vary from faint circular areas of
alopecia and hair coat color and density changes
to small or larger nodules, to large ulcerated
fibromatous and invasive tumors. The rate of
progression is very variable - some remain static
for years others exacerbate rapidly. Inappropriate
interference is a common cause of progression
towards the more aggressive forms.
• Diagnosis: because biopsy can → exacerbation,
diagnosis on clinical grounds is probably
reasonable; confirmation by biopsy may be
justifiable in difficult locations and where there
is a doubt about the diagnosis; if biopsy is
performed a definite plan for prompt therapy must
Fig. 1 Sarcoids. Image provided by Prof. Derek Knottenbelt.
be available. Where a horse has several different
lesions (a diagnosis that can be classified as typical
sarcoid), a tentative diagnosis can be made.
• Treatment: therapeutic options are severely
limited. If treatment is clinically difficult or
may have significant welfare implications and
• Volume 21 Issue 3 | September 2019 •
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