Carotid Body Tumors

Abstract

Carotid body tumors (CBTs) are the most common type of paraganglioma found in the neck. CBTs are slow-growing tumors that characteristically splay the carotid bifurcation and can encapsulate the external or internal carotid artery. Clinically, CBTs usually present as an asymptomatic anterior neck mass. In larger tumors, they can be associated with neck fullness, pain, dysphagia, odynophagia, hoarseness, and stridor. CBTs are typically classified into three groups that related to the difficulty of resection using the Shamblin classification. CBTs are frequently diagnosed by clinical examination or found incidentally on imaging studies. Color-flow duplex is the ideal initial diagnostic test for CBTs. CBTs appear as a characteristically well-defined hypoechoic mass that splays the carotid bifurcation and is hypervascular. Cross-sectional studies, such as CT angiography (CTA) or MRA, are increasingly used to determine the relationship of the tumor with the artery bifurcation and the likely location of the cranial nerves. CBTs classically receive their blood supply from the external carotid artery through multiple small branches of the ascending pharyngeal artery. Difficulty of resection of these tumors is determined by their size and involvement with adjacent structures. Occasionally, preoperative embolization of the ascending pharyngeal artery can be performed for large tumors; however, this may lead to increased inflammation when surgery is delayed more than 1–2 days. Resection of these tumors may require reconstruction of the internal carotid artery with either patch or interposition graft (saphenous vein). Complications include bleeding, cranial nerve injury (as high as 20–25%), and loss of the baroreceptor reflex. Stroke is a rare complication of this surgery.