Vaginal Fibropapilloma in a Heifer

Abstract

The term fibropapilloma is used to refer to a papilloma virus induced benign tumor in the skin. A 6 month old Holstein calf was referred to the veterinary hospital of this school having multiple masses in the vaginal roof. The animal had 4-5 pinkish closely associated masses attached to the dorsal commissure of the vaginal roof about 5 cm deep into the vagina. Histopathological examination revealed the masses similarly consisted of abundant proliferating fibrous tissue with an epithelial covering of variable thickness. The pegs of the epithelium that typically extend into the subjacent connective tissue demonstrated papillomatous features with irregular hyperplasia and epidermal rete ridges. In the epidermis, the stratum spinosum was hyperplastic and the koilocytes included variably sized keratohyalin granules and a few intranuclear inclusion bodies were present. The dermis consisted of densely packed fibroblasts and dense irregular collagenous connective tissue. In Masson’s trichrome staining, the bundles of collagen were blue in color. Immunohistochemically, the neoplastic cells were positive for cytokeratin but negative for S-100. Based on routine histopathological, special staining and immunohistochemical findings, the tumor was diagnosed as vaginal fibropapilloma.