A 5-year-old, 5.4 kg, intact female mixed-breed dog presented with acute respiratory distress. Echocardiography showed pulmonary valvular stenosis with narrowing valvular annulus, ventricular septal defect, overriding aorta and the right ventricular hypertrophy. Other concurrent abnormality included sternal deformity, peritoneopericardial diaphragmatic hernia. The dog was diagnosed as a Tetralogy of Fallot. Despite treatments, the dog died 4 days after hospitalization due to respiratory arrest. A complete necropsy was performed. Histopathologic examination of the lung revealed lipid granuloma, pulmonary leukocytoclastic necrotizing vasculitis of the medium- and large-sized arteries, pulmonary thrombosis, and fibrinoid depositions. This case report describes pulmonary leukocytoclastic necrotizing vasculitis in a dog with Tetralogy of Fallot and peritoneopericardial diaphragmatic hernia. To our knowledge, this is first report of leukocytoclastic necrotizing vasculitis of the pulmonary arteries in uncorrected Tetralogy of Fallot with peritoneopericardial diaphragmatic hernia.

Key words: Hypoxia, Leukocytoclastic vasculitis, Pulmonary necrotizing Vasculitis, Pulmonary vasculitis, Tetralogy of Fallot