NOTE Internal Medicine Abdominal Aortic Chondrosarcoma in a Dog

A 14-year-old, mixed breed dog was presented with acute pain and paresis of the hindlimbs. Ultrasonography revealed an intraluminal mass and an abrupt halt of blood flow signal in the distal abdominal aorta. The mass had homogeneous hyperechoic echotexture compared with blood flow. Although clinical presentation suggested a thromboembolism and pituitary dependent hyperadrenocorticism was suspected as a predisposing cause based on adrenal function tests and ultrasonography, an aortic chondrosarcoma originating from the distal abdominal aorta was diagnosed with histologic examination. Primary aortic sarcoma is extremely rare, and extraskeletal chondrosarcoma is only reported in 2 cases previously. Aortic neoplasm should be included in differential diagnosis when an intraluminal aortic mass is observed on ultrasonography and acute paresis of hindlimbs is shown.