In 1950, the term "chemodectoma" was proposed as the generic name for tumors arising from the nonchromaffin neuroepithelial cells located in the adventitia of blood vessels derived from the branchial arches. The ganglia of the glossopharyngeal and vagus nerves are also sites of the neoplasms.1-3 These cell aggregates have neither endocrine nor motor function. They have the propensity for perceiving chemical changes in the circulatory system and thus act as a sensory component in a reflex arc which allows transmission of impulses centrally over afferent parasympathetic nerve fibers. In this way, blood flow and respiratory rate may be controlled.4,5 Although these neuroepithelial cells are found in many sites, by far the most common location of neoplasm is the carotid body at the main carotid bifurcation. This entity was first described by Marchand in 1891.6Chemodectomas arising from aortic bodies situated in the mediastinum are rarely seen.7