Hypertrophic osteopathy in 4 white-tailed deer, with a literature review.

Hypertrophic osteopathy (HO) is a condition in which periosteal bone forms along long bone diaphyses and metaphyses. Lesions generally affect all 4 limbs, and often involve the distal portions. The pathogenesis is incompletely understood, and many, but not all, cases are associated with concurrent neoplasia or space-occupying masses. Among veterinary species, most cases are reported in dogs, cats, and horses, with sporadic cases in other domestic and non-domestic species. In cervids, this condition is often associated with fungal granulomas, typically in the lung. We report HO, with findings consistent to other veterinary species, in a farmed white-tailed deer (WTD) with bacterial pneumonia and in 3 free-ranging WTD, one of which had fungal pneumonia. Recognition of HO in WTD and potentially associated conditions can lead to improved sample collection in the field. Such information can improve characterization of the disease, complement our understanding of comparative pathology of this condition, and raise awareness among individuals or institutions working with cervids.