Equine sarcoids. A clinical and epidemiological study in relation to equine leucocyte antigens (ELA)
Broström, H.
Acta Veterinaria Scandinavica 36(2): 223-236
1995
ISSN/ISBN: 0044-605X PMID: 7484549 Document Number: 447335
Associations between clinical parameters of sarcoids and the equine leukocyte antigen system (ELA) were analysed for 120 Swedish horses. Median age of affected horses was 5.2 years, the majority presented with solitary tumours between 2 and 5 cm in diameter and the ventral abdomen was the predilection site. Clinical signs first appeared at a median age of 3.5 years, and sarcoids at different locations first appeared at different ages. Lesions at different sites differed in size, and multiple tumours, early onset, long duration, and older age all had an association with large size. Clinical manifestations of sarcoids and the association between certain ELA-specificities and early onset (A5) and increased recurrence rates after surgery (W13), in addition to increased prevalence (A3W13), strengthened further the conclusion that some horses are inherently predisposed to sarcoid growth. Unassociated with any clinical parameters, one third of the untreated horses became free of sarcoids due to "spontaneous" regression, perhaps as a result of immune responses against the tumours. 70% of the horses were treated (mostly by excision), and large size was the main parameter promoting treatment. Excision had no significant effect on possible remaining sarcoids. Recurrence rate after first treatment was about 35%, with the majority of tumours recurring within 4 months. Early onset, long duration, large size, and localization to distal limbs all appeared to increase risk of recurrence. Early treatment, performed under general anaesthesia in recumbency which permitted wide excision and measures to avoid autoinoculation, significantly reduced recurrence rates.