Intra-abdominal heterotopic mesenteric ossification associated with intestinal volvulus in a sow (Sus scrofa domesticus)

An adult, female, mixed breed sow from a commercial breeding unit, with a clinical history of lethargy, poor body condition, hypersalivation, dyspnoea and reddened ears, was submitted for necropsy. Post-mortem examination identified the presence of an intestinal volvulus, which developed around an osseous intra-abdominal mesenteric lesion. Gross pathology and histopathology combined with post-mortem computed tomography (CT) of the mass confirmed the lesion as intra-abdominal heterotopic mesenteric ossification (IHMO), according to criteria applied to human disease. This report highlights a rare case of porcine IHMO, a poorly understood metaplastic condition, comparable to the human disease. We highlight the importance of a combination of CT and histopathology to reach a final diagnosis of the disease. Histopathology and further investigation of similar cases may contribute to a better understanding of the pathogenesis in animals, which is currently poorly understood.