Teaching Case

We present a case of a 72 year-old female presenting with a painless right cervical mass.

Duplex ultrasound, CT and angiography were performed.

Duplex ultrasound image (fig.1) showed a hypoechoic solid mass with internal vascularization located at the carotid bifurcation, separating the internal and external carotid arteries.
CT images (fig.2) depicted a well-defined soft tissue mass at the level of the carotid bifurcation, which splays the internal and external carotid arteries, with intense and rapid enhancement after intravenous administration of contrast material.
Carotid angiogram (fig.3) images showed the carotid body tumor, presenting as a hypervascular lesion with multiple enlarged feeding arteries.

Background

The carotid body is a sensory organ located within the adventitia of the common carotid artery near the carotid bifurcation that plays a fundamental role in multiple physiologic processes such as regulation of respiratory and heart rate and blood pressure, by releasing a variety of neurotransmitters (including acetylcholine, adenosine triphosphate and dopamine) [1].
The most common pathology of the carotid body is the carotid body tumor, a paraganglioma originating from the glomus cells present in this structure [2].

Clinical Perspective

These tumors present as a slowly growing, painless lateral neck mass (as in the case we present, although some patients may experience local pressure symptoms like neck or ear pain). Symptoms may also be related to catecholamines release, giving place to hypertensive crises and arrhythmias. Typically, they are moveable in the horizontal plane but not in the vertical plane [3].

Imaging Perspective

Carotid body tumors are highly vascular lesions that characteristically splay apart the internal and external carotid arteries (lyre sign). The dense vascularity of these tumors is reflected in their imaging appearance.
Duplex ultrasound usually showed a well limited hypoechoic solid mass with abundant flow in power Doppler and low resistance flow with a high diastolic component on spectral analysis (Fig.1) [3].
CT allows characterization after intravenous administration of contrast material, and a soft tissue mass at the level of the carotid bifurcation with intense and rapid enhancement was identified (Fig.2) [2].
Angiography showed multiple enlarged feeding arteries [4]. (Fig.3)

Outcome

Most (95%) of these tumors are benign. Rarely can be malignant, defined as the presence of metastases (mainly to the liver, lymph nodes, lung and bone) [3].
Surgical resection is the treatment of choice, but the highly vascular nature of these neoplasms pose a therapeutic challenge [2]. Imaging predicts surgical morbidity, which is related to the size and relationship of the tumor with the carotid vessels (Shamblin classification of carotid body tumours) [5]. In our case surgery was performed, with no signs of recurrence until this moment.

Take Home Message, Teaching Points

Due to their highly vascular nature and typical imaging features, most carotid body tumors can be diagnosed solely on imaging.
Imaging characterization of tumor dimensions, blood supply and relationship with the carotid vessels is useful in the management of these patients.

Written informed patient consent for publication has been obtained