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Basics ⬇

Basics

Overview

  • Cutaneous mucous membrane lesions of dogs and cats caused by various papilloma viruses.
  • Dogs: oral papillomatosis, venereal papillomatosis, exophytic cutaneous papillomas, cutaneous inverted papillomas, multiple papillomas of the footpad, canine pigmented viral plaques.
  • Cats: feline cutaneous papillomas, feline cutaneous fibropapillomas (feline sarcoids), feline viral plaques.
  • Viral plaques may progress to BISC, SCC or invasive carcinoma.

Signalment

Dogs

  • Puppies and young adult dogs-oral papillomatosis, venereal papillomatosis, multiple papillomas of the footpad, cutaneous inverted papillomas, canine pigmented viral plaques (breed predisposition).

  • Older dogs-exophytic cutaneous papillomas, cutaneous inverted papillomas.
  • Miniature schnauzers and pugs-pigmented viral plaques; associated with immunosuppression in other breeds.

Cats

  • More common in older cats; associated with immunocompromise (e.g., FIV).
  • Feline sarcoids: younger cats, especially those with outdoor exposure.

Signs

Dogs

  • Cutaneous papillomas-pedunculated, fronds of epithelium, up to 1 cm in diameter located anywhere.
  • Canine papillomavirus-most often oral mucosa, hard palate, epiglottis; may interfere with prehension, swallowing; trauma results in halitosis and ptyalism; may be confined to genital or eyelid regions.
  • Cutaneous inverted papillomas-less common, multiple lesions often found with a central pore; on ventral abdomen; caused by distinctly different papilloma virus from COPV.
  • Multiple papillomas affecting footpads in younger dogs-firm, hyperkeratotic lesions causing discomfort and lameness.
  • Canine pigmented viral plaques-miniature schnauzers, pugs; Boston terriers, French bulldogs; rarely transform to SCC; ventral abdomen and inner thigh region.

Cats

  • Feline cutaneous papillomas-rare.
  • Feline viral plaques-more common; may progress to BISC or invasive carcinoma.
  • Feline sarcoid lesions-uncommon.
  • Cats 10 years or older; other systemic disease causing immunosuppression (e.g., FIV).

Causes & Risk Factors

  • Oral papillomas affecting naive dogs and recovered animals develop lifelong immunity.
  • Dogs-cutaneous papillomas thought to involve cell-mediated immunologic defects.
  • Older, immunosuppressed cats develop plaques and BISC.
  • Canine pigmented viral plaques-strong breed predisposition.

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

Dogs

  • Oral cavity, oropharynx-fibromatous epulis, transmissible venereal tumor, SCC.
  • Cutaneous-sebaceous hyperplasia, acrochordon.
  • Pigmented plaque-melanocytoma.
  • Inverted-infundibular keratinizing acanthoma.

Cats

Eosinophilic granuloma, complex, actinic keratoses, cutaneous lesions of FeLV, multicentric SCC in situ, SCC.

CBC/Biochemistry/Urinalysis

Normal

Other Laboratory Tests

Cats: FeLV, FIV

Imaging

N/A

Diagnostic Procedures

  • Gross lesions have a typical appearance.
  • Biopsy for histopathology; immunohistochemistry demonstrates viral antigens within lesions; PCR not definitive.

Pathologic Findings

  • Dependent upon syndrome; all lesions share cytopathic effects of papillomavirus infection: hyperkeratosis, acanthosis, koilocytes in stratum spinosum, abnormal, large keratohyalin granules in statum granulosum.
  • Viral pigmented plaques may lack koilocytes and viral inclusion bodies.

Treatment ⬆ ⬇

Treatment

Medications ⬆ ⬇

Medications

Drug(s)

  • -Interferon-30 units/cat PO q24h.
  • Imiquimod-applied to individual lesions three times/week for 4 weeks.

Contraindications/Possible Interactions

Imiquimod-potential for human exposure when applying to patient; causes severe localized reaction; use with caution at mucocutaneous junctions.

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring

Monitor for signs of malignant transformation to SCC.

Prevention/Avoidance

  • Separate dogs with oral papillomas from susceptible animals.
  • Commercial kennels-may consider autogenous vaccination.

Expected Course and Prognosis

  • Dogs-prognosis good; incubation period 1–8 weeks; regression usually 1–5 months; lesions persist 24 months or more.
  • Cats-long-term prognosis for plaques and BISC depends on concurrent diseases.

Miscellaneous ⬆

Miscellaneous

Associated Conditions

N/A

Age-Related Factors

Dependent upon viral strain

Zoonotic Potential

Papillomaviruses: species specific

Pregnancy/Fertility/Breeding

  • Venereal lesions may preclude breeding.
  • Transmission of viral infection likely; especially when active lesions present.

Synonyms

Bowen's disease = BISC

Abbreviations

  • BISC = bowenoid in situ carcinoma
  • COPV = canine oral papillomavirus
  • FeLV = feline leukemia virus
  • FIV = feline immunodeficiency virus
  • PCR = polymerase chain reaction
  • PV = papilloma virus
  • SCC = squamous cell carcinoma

Author Elizabeth R. May

Consulting Editor Alexander H. Werner

Suggested Reading

Miller WH, Griffin CE, Campbell KL. Muller & Kirk's Small Animal Dermatology, 7th ed. St. Louis, MO: Saunders, 2013, pp. 343–351.