The Effects of Preoperative Embolization on the Outcomes of Carotid Body Tumor Surgery

Abstract

C arotid body originates from the third branchial arch mesoderm and from ectodermal-derived neural crest lineage the normal carotid body is an ovoid pink structure approximately 6 x 4 x 2 mm in size. It is commonly described, perhaps erroneously, as located posteriorly within the adventitia at the bifurcation of common the carotid artery. The gland is innervated by the glossopharyngeal nerve. Its blood supply is the richest per gram of tissue of any tumor and is derived from vasa vasorum, branches of the vertebral artery, and, predominately, from the external carotid artery via its branches. Characteristic feature of carotid body tumors is slow growth rate, which is reflected clinically by the delay between the first symptoms and the diagnosis, which averages between 4 and 7 years of age. Carotid body tumor usually presents as a lateral cervical mass, which is often less mobile in the craniocaudal direction because of its adherence to the carotid arteries. The mass of the carotid body tumor is located lateral to the hyoid, whereas the vagal body tumors are found more cranially behind the ascending part of the mandible and sometimes project into the lateral oropharynx as a pulsating mass with displacement of the tonsil, soft palate, and uvula. Many carotid body tumors are pulsatile by transmission from the carotid vessels or less commonly expand themselves, reflecting their extreme intrinsic vascularity. Sometimes, a bruit may be heard by auscultation, but can disappear with carotid compression. Angiography of the carotid system was the final diagnostic method for these lesions. Today, the diagnosis can be made with MR imaging in axial and coronal planes. The settings should include gadolinium-enhanced three-dimensional time-of-flight sequences, which demonstrate the extension of the tumor in relation to the carotid arteries and the involvement of the base of the skull. Additionally, MR imaging provides a perfect screening tool for multifocal (i.e., occult) head and neck paragangliomas. Magnetic resonance imaging and MR angiography provide good insight into the vascularization of the tumor and the origin and contribution of the several branches of the external carotid Differential diagnosis, including other vascular or nonvascular tumors in the neck, can also be made. These include branchial cleft cysts, metastatic carcinomas, lymphomas, schwannomas, salivary gland tumors, and carotid artery aneurysms. Angiography, though no longer the first-line imaging method, remains valuable for preoperative evaluation, and the possibility of preoperative embolization. Angiography can confirm the