Aortic body tumors in dogs

The purpose of this essay was to review the literature and describe the patophysiology, diagnosis, microscopic and macroscopic appearance of aortic body tumors in dogs. The tumors originate from the chemoreceptor organs situated at the base of the heart. The chemoreceptor organs are neuroendocrine cells responsible for surveillance of changes in e.g. the blood pH. Aortic body tumors are rare and represent 7 % of the total cases of primary cardiac tumors in canines. Despite their low prevalence the tumors are the second most common cardiac tumor. However, they are of clinical importance because they can cause cardiac failure and cardiac tamponade among other symptoms. Brachycephalic breeds such as Boxers, Boston bull terriers and English bulldogs have a high prevalence. However, there are other brachycephalic breeds e.g. Pugs where the prevalence is not higher than the average among all breeds. The etiology is not fully known but reports indicate a genetic and/or breed predisposition. Theories suggest that chronic hypoxia and “Brachycephalic airway syndrome” serves as contributing factors. The tumors measure 0,5 – 12,5 cm in diameter and the size of the tumor determines the symptoms including cardiac failure and cardiac tamponade. A benignant behavior is mostly seen and the tumors are expansive which causes many of the symptoms. There are also infiltrative tumors and they cause symptoms as well though they are less common. Tumors can be discovered by ultrasonography or radiography and diagnosis can be confirmed with histological stains such as hematoxylin and eosin staining together with immunohistochemistry by labeling the tumor with a neuroendocrine marker e.g. chromogranin A.