here - Australian College of Veterinary Scientists

Equine sarcoidosis
Sonya Bettenay
These notes include findings from cases in a multi-centred study collated by Dr Christine Loewenstein, Dr
Sonya Bettenay and Dr Ralf Mueller,with co-investigators Dr Janet Littlewood, Dr Wayne Rosenkrantz,
Dr Claudia von Tscharner, Dr Fernando Ramiro-Ibanez and Dr Sherry Myers
.
Equine sarcoidosis (generalized or systemic granulomatous disease) is a rarely
reported disease characterized clinically by multifocal to generalized exfoliative
dermatitis and histologically by prominent multinucleated giant cell granulomas (also
occur in up to 50% cases in other organ systems). Equine sarcoidosis has been
named after the human sarcoidosis syndrome, so named because of these
characteristic “naked” granulomas. It should not be confused with the far more
common “equine sarcoid”, which is a fibroblastic tumorous lesion with various
clinical presentations.
Only few reports about equine sarcoidosis are published. Since the first published
case (Anderson and others 1983) there have been only 6 reports with a total of 10
cases (Duell and others 1997, Heath and others 1990, Peters and others 2003, Rose
and others 1996, Sellers and others 2001, Woods and others 1992) and several
general review articles (Mullowney 1985, Scott 1988, Scott 1991, Scott 1992,
Stannard 1987, von Tscharner and others 2000). All of the reported cases showed
signs of general disease such as apathy, fever, weight loss or lymphadenopathy.
Four of the horses died or were euthanized and underwent post mortem
examination. They had involvement of internal organs including brain, lung, heart,
lymph nodes, liver, kidney, pancreas, thyroid and adrenal glands (Anderson and
others 1983, Peters and others 2003, Sellers and others 2001, Woods and others
1992). Eight horses showed dermatologic symptoms such as scaling, crusting,
alopecia and nodules (Duell and others 1997, Heath and others 1990, Rose and
others 1996, Sellers and others 2001, Woods and others 1992). 50% of 8 horses
recently presented (Spiegel 2005) were said to have pulmonary involvement.
These findings are in contrast to the human disease where skin lesions are present in
only 16 to 36% of the cases (Braverman 1998). Pulmonary lesions, however are
most common and seen with 90% of the patients (Braverman 2003). Human
sarcoidosis is a multisystemic disease characterised by sarcoidal granulomas.
Sarcoidal granulomas may also be associated with foreign bodies. They are discrete,
round to oval and composed of epithelioid histiocytes and multinucleated giant cells
with very occasional lymphocytes. This is in contrast to typical granulomas which are
ACVSC Proceedings Dermatology Chapter Science Week 2005 59