This is all I could find
"Skin Tumors
Hunters sometimes shoot a deer with lumps on the skin. These bumps are usually non-cancerous tumors called fibromas or papillomas. Viruses cause both. The only difference is that fibromas grow either from the skin or from the layer beneath, while papillomas grow only from the skin. Both lumps are dark-colored and hard to the touch. These growths generally do not cause problems for deer, but people are curious about them. Hunters may feel venison is inedible because of these tumors. Since lumps are usually found only in the skin, not in the muscles, there is generally no problem. But tumors located inside a deer's body might be cancerous and the venison should not be eaten."