Cutaneous Inverted Papillomas in Dogs

Abstract

Abstract. Inverted papillomas of the skin occurred in five dogs. Lesions were 1-2 cm, circumscribed, flasklike structures below the level of the surrounding normal skin. Walls of the structures consisted of hyperplastic epidermis, forming thin papillary projections on thin fibrovascular stalks. Cells in the stratum granulosum had clear cytoplasm, numerous keratohyalin-like granules of various sizes, and poorly defined intranuclear inclusions. These cells stained positively for papillomavirus group-specific antigens by both the peroxidase-antiperoxidase and avidin-biotin methods. Virions with a mean diameter of 35.7 nm were present within nuclei in cells of the stratum granulosum when examined by electron microscopy. In situ DNA hybridization, using a canine oral papillomavirus probe, localized papillomavirus DNA in canine oral papillomas, but not in canine cutaneous squamous or inverted papillomas, suggesting that a different papillomavirus type was present in the latter lesions. Although these lesions resembled intracutaneous cornifying epitheliomas (keratoacanthomas), they appear to be a distinct lesion, probably with a different etiology Dogs develop a variety of cutaneous neoplasms; the etiology of many are unknown. Papillomavirus antigens have been detected in cutaneous squamous papillomas and some squamous cell carcinomas, but not in canine intracutaneous cornifying epitheliomas, trichoepitheliomas, pilomatrixomas, or sebaceous adenomas. 16 We describe here five cases of inverted papillomas in dogs which superficially resemble intracutaneous cornifying epitheliomas (keratoacanthomas), are morphologically distinct from the common cutaneous squamous papilloma, and contain papillomavirus antigens. Materials and MethodsSurgical biopsies from five dogs were fixed in 10% neutral buffered formalin, processed routinely, embedded in paraffin, sectioned at 6 pm, and stained with hematoxylin and eosin (HE). Serial sections were tested for the presence of papillomavirus group-specific antigens by both the peroxidaseantiperoxidase (PAP)16 and avidin-biotin complex (ABC) techniques. Tissues removed from paraffin blocks of three cases were reembedded in epon-araldite, sectioned, and examined in an electron microscope to confirm the presence of virus.Sections for in situ hybridization were deparaffinized, treated with a prehybridization mixture of 50% deionized formamide in 0.3 M NaCl and 0.03 M Na, citrate, and incubated with the hybridization mixture.6 The hybridization mixture was prepared using cloned canine oral papillomavirus DNA24, nick translated in the presence of 66.8 pmoles ,%-labelled dATP.I3J7 The resulting 35S-labelled DNA had a specific activity of greater than 1 x lo8 cpmhg. Following a 4-hour incubation with the hybridization mixture, the sections were rinsed, dehydrated with ethanol, and applied to NTB-2 nuclear track emulsion (Kodak). The emulsion was exposed for 7 days, slides developed in a 1 : 1 mixture of D-19 (Kodak) and H,O, rinsed in 1 O/o glacial acetic acid, fixed in Kodak Rapid Fix, stained wi...

Severe Papillomavirus Infection Progressing to Metastatic Squamous Cell Carcinoma in Bone Marrow-Transplanted X-Linked SCID Dogs

“…Canine oral papillomas normally occur in young dogs, have a typical exophytic histologic phenotype, and usually spontaneously regress within 4 to 8 weeks (41). Cutaneous papillomas occur uncommonly in the dog and are caused by a papillomavirus that differs from COPV, suggesting at least a second type of canine papillomavirus (12,33,49,52). Reports describing cutaneous papillomas have primarily been for dogs receiving various forms of immununosuppressive therapy, with the papillomas spontaneously regressing shortly after cessation of the immunosuppressive drug (8,33,49,52).…”

Cutaneous Papillomatosis in a Dog with Malignant Lymphoma following Long-Term Chemotherapy

“…7 In other reports, dogs ranging in age from 8 months to 7 years had multiple cutaneous inverted papillomas containing papillomavirus. 3,8 Although most viral papillomas affect oral mucous membranes in dogs, experimental induction of virus-associated cutaneous papillomas has been described. 2,11 In 1 young dog, oral and cutaneous papillomatosis developed after corticosteroid treatment, and demodecosis accompanied the onset of papillomatosis, suggesting immunocompromise as the underlying risk factor.…”

“…The nematode and the ova were identified as Capillaria sp. 3 The stratified squamous epithelial lining of the anal sac was diffusely hyperplastic and had many narrow tunnels in which cross sections of Capillaria sp., ova, or both were present (Figs. 2, 4).…”

In vitroand Animal Models for Antiviral Therapy in Papillomavirus Infections

“…Papillomas have been identified in the oral cavity (including buccal mucosa, tongue and soft palate), skin, conjunctiva, penis and vulva (Belkin, 1979;Bonney et al, 1980;Hare & Howard, 1977;Sansom et al, 1996;Sundberg et al, 1984;Tokita & Konishi, 1975). The cutaneous lesions include both squamous papillomas (Campbell et al, 1988;Watrach et al, 1969), cutaneous inverted papillomas (Campbell et al, 1988;Shimada et al, 1993) and squamous cell carcinomas (Watrach et al, 1970). Squamous cell carcinomas have been associated with the use of a live canine oral papillomavirus (COPV) vaccine (Bregman et al, 1987;Ghim etal., 1995).…”

“…The canine 'pigmented epidermal nevus' is associated with a papillomavirus, and some parallels have been drawn with human EV (Nagata et al, 1995). It is thought that there are several types of canine papillomavirus 390 (Campbell et al, 1988;Delius et al, 1994), each having a different tissue tropism which may be expanded by natural or iatrogenic immunosuppression. This theory is supported by the recent finding of a new papillornavirus isolated from cutaneous papules in an immunosuppressed dog (Le Net et al, 1997).…”