Dissecting thoracoabdominal aortic aneurysm in a free-ranging Florida panther (Felis concolor coryi)

A 12-yr-old female free-ranging Florida panther (Felis concolor coryi) was found dead in good flesh. The panther had a ruptured thoracoabdominal aneur ysm and 0.5 L of unclotted blood in its thorax. Intimal plaques 6.0 X 3.0 X 3.0 cm and 4.0 X 3.0 X 1.0 cm were present in the thoracic and abdominal a orta extending below the bifurcation of the renal arteries. Histologic exam ination revealed necrohemorrhagic aortitis with a mixed inflammatory infilt rate of lymphocytes, macrophages, and neutrophils. Death was almost certain ly due to exsanguination and hypovolemic shock secondary to the ruptured an eurysm, and the aortitis with the resultant aneurysm may have been secondar y to an infectious or a toxic process. This is the first reported death of a free-ranging mammal from a ruptured aortic aneurysm.