Vulvar squamous cell carcinoma in situ within viral papillomas in an aged Quarter Horse mare

Abstract

Summary This report describes the diagnosis and treatment of vulvar papillomatosis with carcinoma in situ in a 25‐year‐old mare. Papillomavirus was demonstrated via immunohistochemical staining of biopsies of the lesion. The papillomas were removed via laser excision and the surrounding vulvar tissue injected with 5‐fluorouracil. Additional more extensive laser excisions were required due to recurrence.

Persistent, widespread papilloma formation on the penis of a horse: a novel presentation of equine papillomavirus type 2 infection

“…The large number and lack of either resolution or progression of lesions over more than 2 years is unusual. Equine genital papillomas are typically described as solitary and progressive, 9,10 although one text mentions that some remain static for many years 9…”

“…The large number and lack of either resolution or progression of lesions over more than 2 years is unusual. Equine genital papillomas are typically described as solitary and progressive, 9,10 although one text mentions that some remain static for many years. 9 In the present case, IHC and ISH were used to demonstrate PV antigen and DNA, respectively, within the nuclei of epithelial cells in papillomas but not in adjacent, histologically normal epithelium.…”

“…Evidence suggests that PVs may be a significant cause of SCCs in humans and domestic mammals. 12 Equine genital papillomas have been reported to progress to SCCs, 10,13 and EcPV-2 has recently been associated with the development of equine penile SCCs. [1][2][3] In the present case, despite persistent PV infection and the presence of numerous papillomas, there was no evidence of progression to SCC within a 2 year period.…”

Squamous cell carcinoma of the paranasal sinuses in two horses

“…1999). A possible involvement of equine papilloma virus in the aetiology of SCC is suggested (Smith et al . 2009) and the presence of chronic inflammation in the tumour tissue might support a potential viral component (Elce 2009).…”

Equus caballus papillomavirus‐2 (EcPV‐2): An infectious cause for equine genital cancer?

“…Chronic exposure of the equine penile mucosa to smegma within the prepuce has been proposed as a predisposing cause of SCC in the penis, although there is little epidemiological data to support this hypothesis (Cotchin 1977). The aetiology of vulval SCC in horses has not been investigated thus far, although transformation of a virally‐induced vulval papilloma to a carcinoma in situ has been described in a horse (Smith et al . 2009).…”