Cutaneous fibromas (also known as deer warts[1]) are common neoplasms occurring in wild and domestic deer of many species and are caused by host-specific viral infections.[2][3][4] The fibromas occur most frequently in animals under 2 years of age, with cases in older deer reported occasionally or rarely.[2]
Deer fibromas appear on the skin as hard and round tumors that can be up to 1 cm in diameter. The tumors are blackish or brown and have a rough-textured surface. They do not cause the animal harm unless clumps of fibromas interfere with breathing, eating, or walking.
Fibromas have been reported in white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), fallow deer (Cervus dama), red deer (Cervus elaphus), roe deer (Capreolus capreolus), Sika deer (Cervus nippon), moose (Alces alces), and caribou (Rangifer caribou)."[5] They occur across the entirety of the white-tail deer's range.[1]