Sarcoid Transformation at Wound Sites

Equine sarcoids are likely caused by bovine papillomavirus. Sarcoid-affected horses are capable of transmitting the virus, often by flies, to other horses to cause development of sarcoids. Early signs that a sarcoid is developing within a wound are dehiscence, unhealthy appearance of granulation tissue, lack of wound contraction, and inability to control exuberant granulation tissue. Sarcoids in a wound are difficult to diagnose histologically because sarcoid tissue is often admixed with granulation tissue. Pathologists unfamiliar with the histological appearance of sarcoids often misdiagnose the lesion. Recurrence of a sarcoid after simple surgical excision is common. Other treatments that may offer better success than excision include: cryotherapy; laser surgical excision; immunotherapy in in form of cell-wall extracts of mycobacteria or subcutaneous implantation of sarcoid tissue; repeated topical application of a cytotoxic drug, such as cisplatin, administered alone or in combination with electric-impulse therapy, the anti-mitotic drug, 5-flurouracil, or an antiviral ointment, such as acyclovir or imiquimod; and radiation therapy. Sarcoid contamination of wounds can be prevented by covering wounds, if possible, and by fly control.