Camelid mucoutaneous fibropapillomas: clinicopathologic findings and association with papillomavirus.

Five camelid mucocutaneous fibropapillomas with histologic features similar to equine sarcoids were diagnosed. They were characterized by a dermal fibroblastic proliferation and overlying, often ulcerated hyperplastic epidermis with thin rete pegs extending down into the dermis. Two of the tumors came from llamas and three from alpacas. Four of the animals were 6-year-old females. The fifth was a 6-year-old castrated male. The fibropapillomas were located on the nose, lip, and cheeks. One of the llama tumors waxed and waned before surgery and recurred and spread after surgery. None of the other tumors recurred. All five tumors were positive for papillomavirus (PV) DNA by polymerase chain reaction testing. Nucleotide sequence analysis of the PCR product from one of the llama fibropapillomas confirmed a unique PV. This report provides the microscopic and clinical features of fibropapillomas in camelids as well as evidence for a PV etiology.