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

Abstract

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.

Keywords: cervid; hypertrophic osteopathy; pneumonia; white-tailed deer.

Figures 1–4.

Hypertrophic osteopathy and associated pneumonia in white-tailed deer. Figure 1. Swelling of the distal forelimb (right) and hindlimb (left) due to periosteal proliferation of the metaphyses and diaphyses of metacarpal and metatarsal bones in case 1. Figure 2. Extensive bony proliferation at the proximal end of the metacarpal bone and adjacent carpal bones in case 4. Figure 3. Radiograph of an affected forelimb with metaphyseal periosteal proliferation of distal long bones in case 4. Figure 4. Severe consolidation and abscessation of the cranioventral lung, consistent with bacterial bronchopneumonia in case 4. Fusobacterium necrophorum and Pasteurella multocida were isolated from the lung.

Figures 5–7.

Bronchopneumonia and hypertrophic osteopathy in a captive white-tailed deer, case 4. Figure 5. High magnification of bacterial bronchopneumonia, with fibrinosuppurative inflammation within small airways. H&E. Figure 6. Expansion of the long bone periosteum by bony trabeculae, which radiate perpendicular to the cortex. H&E. Figure 7. Periosteal bone proliferation; bland, trabecular bone with intertrabecular hematopoietic tissue. H&E.