Sudden death in a Thoroughbred stallion: cardiac tamponade due to transverse aortic rupture with bone metaplasia and calcification

Figures

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  Fig. 1.. Gross findings of the heart. (A) Cardiac tamponade shows severe intrapericardial hemorrhage (*). (B) A perforation of the aorta (dotted arrow) is shown together with epicardial and surrounding hemorrhage. (C) Aortic lumen surface: A transverse rupture (arrowhead) in the aortic wall is shown at the bases of the right semilunar valve and septal semilunar valve (at the junction of the aortic wall and valve). (D) Aortic lumen surface (zoom): The bases of the right semilunar valve and septal semilunar valve are divided into upper and lower halves and transformed into a columnar shape (arrowhead). The valve leaflets of the right semilunar valve to the septal semilunar valve, which are continuous to these bases, are laterally fissured (*).

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  Fig. 2.. Histopathological findings of the transverse aortic rupture. (A, D) Heart side: The aorta wall is mainly composed of disarrayed elastic fibers. (B, E) Around the rupture area: The aorta wall is a mixture of elastic fibers and fibrous osseous metaplasia. (C, F) Aortic rupture part: The aorta wall is mainly composed of fibrous osseous metaplasia with calcification (*). (G) Calcium deposits are seen in elastic fibers and between elastic fibers. (H) Around the rupture area: Calcium deposits are seen between elastic fibers. (I) Aortic rupture part: Calcium deposits are seen around the nuclei of ossified cells. A–C: hematoxylin and eosin, D–F: Elastica Masson, G–I: Kossa stain. A–C and G–I: bar=50 µm, D, E: bar=300 µm, F: bar=100 µm.

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  Fig. 3.. Pathological findings of the cardiac cartilage. (A) Macro photo of cardiac cartilage: Ossification is seen in the center of the cardiac cartilage. (B, C) Micro photos of cardiac cartilage: Osseous metaplasia is seen in the center of the cardiac cartilage. Ao, aorta; CC, cardiac cartilage; OM, osseous metaplasia; Os, ossification; Ru, rupture site; VL, valve leaflet. B, C: hematoxylin and eosin stain. A: bar=1 cm, B: bar=300 µm, C: bar=50 µm.