SKIN TUMOURS OF CERVIDS

  Two types of benign or noncancerous tumours, papillomas and fibromas, were described from deer and moose in the previous edition of this manual.  In the present edition they are included in the same section because accurate classification of them requires histological examination by a pathologist.

   Growths or tumours in the skin of an animal may take many different forms each with a distinctive cellular structure.  Fibromas arise from fibrous connective tissues and papillomas from epithelial tissues.  However, since epithelial tissues rest on a connective tissue base, papillomas, like fibromas, contain fibrous connective tissue.  Fibromas are usually found in the skin or subcutaneous tissues and papillomas, usually in the skin.  The presence of many fibromas is called fibromatosis and of many papillomas, papillomatosis.

   Skin tumours can vary in size from small nodules to large masses.  The smaller growths appear to be round while larger growths are often irregular in shape.  The growths are all firm, the outer surfaces are usually light gray to black in colour, and the texture of the surface may vary from a rough cauliflower-like appearance to a smooth or slightly wrinkled appearance.  Cut surfaces reveal a firm inner core which may be white, grayish-white or pinkish except at the epithelial surface which is often darker.

   Skin tumours are observed most frequently on deer and moose but have been reported from other species of wildlife.

   Fibromas in deer are known to be caused by viruses and a viral origin has been suggested for skin tumours of other cervids.  The deer fibroma virus is considered specific to deer.  Because of this apparent host specificity it is unlikely that man is susceptible to infection from either deer or moose.

   Methods by which skin tumours spread are not well understood.  Transmission from infected to uninfected cervids is thought to be by contact of injured or broken skin with infectious material present either on an infected animal or on vegetation.  Ticks, mites and bloodsucking insects may also be involved in the transmission of the virus.

   Since skin turnouts of cervids are benign and localized, they do not affect the edibility of the meat.

   Tumours for histological examination should be cut open and fixed in 10% formalin rather than be frozen.  Submission of freshly fixed tumours to the diagnostic lab will aid greatly in accurate histological classification.

Selected References:

   Friend, M. 1967.  Skin tumors in New York deer.  Bull.  Wildl.  Dis.  Assoc.  3:102-104.

   Fyvie, A. 1968.  Papillomatosis in a moose.  Res.  Note (Wildl.) Ont.  Dept.  Lands Forests,  No. 12,  7 p.

   Smith, H.A. and T.C. Jones. 1966.  Veterinary pathology, 3rd ed.  Lea and Febiger, Philadelphia.

   Thornton, H. 1962.  Textbook of meat inspection, including the inspection of rabbits and poultry, 4th ed.  Baillière, Tindall and Cox, London.