A rare case of intramural patent ductus arteriosus in a dog: anatomic, histopathologic, and radiographic features

A 5-year-old dog was evaluated for a lethargy and respiratory distress. Radiograph revealed cardiomegaly with pleural effusion, and the dog died during a thoracocentesis. At necropsy, the descending aorta and pulmonary trunk were dilated and in close contact, but there was no external evidence of a patent ductus arteriosus (PDA). When the descending aorta was opened however, an ostium opening into the pulmonary trunk was evident. Histopathological investigation revealed that the intramural PDA resembled vascular tissue with a structure and architecture. The diagnosis was an intramural PDA, an extremely rarely reported type of PDA in the dog.