Equine Sarcoids Study Guide

Overview and Clinical Importance

Equine sarcoids are the most common cutaneous neoplasm in horses, representing approximately 20% of all equine tumors and 36-40% of all equine skin tumors worldwide. These locally invasive fibroblastic tumors are associated with bovine papillomavirus (BPV) types 1 and 2, and while they do not metastasize, they can cause significant welfare concerns, economic losses, and functional impairment, particularly when located periocularly or in areas subject to tack contact.

Sarcoids affect horses of all breeds, ages, and sexes, though peak incidence occurs between 2-9 years of age. The condition is notoriously difficult to treat, with high recurrence rates following therapy, making early recognition and appropriate management essential clinical skills for the NAVLE examination.

Etiology and Pathogenesis

Bovine Papillomavirus Association

Bovine papillomavirus (BPV) types 1 and 2 (and more recently type 13) are strongly implicated in sarcoid development. BPV DNA has been detected in up to 100% of sarcoid tissue samples. Key points regarding BPV involvement include: