Massive carotid body tumor

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A 45-year-old female patient, who has had a slow-growing, painless and nonpulsatile mass on the left side of her neck for the past 20 years, was presented to the hospital. She was asymptomatic and her past medical history was unremarkable. A CT angiography (CTA) was requested for pre-operative evaluation.

CTA images revealed a large, hypervascularized and heterogeneous mass in the left carotid space, measuring 11.8 x 9.6 cm in size, and extending from the thoracic inlet up to the parapharyngeal space. The left common carotid artery (CCA) was severely encased. The bifurcation, as well as the course of the internal (ICA) and external (ECA) carotid arteries were not seen. The left internal jugular vein (IJV), the external jugular vein (EJV), as well as multiple tortuous collaterals were displaced posterolaterally and were adherent to the mass. 

The Circle of Willis (COW) was well established, with sufficient collaterals. There was no indication of bone erosion at the base of the skull. The vertebral arteries were bilaterally patent. The diagnostic impression was that of a left carotid body tumor (CBT), Shamblin grade III. The patient subsequently underwent tumor resection, along with ligation of the left CCA, IJV and EJV. The histopathology report concluded a paraganglioma. The postoperative recovery was uneventful. There was no evidence of brain ischemia after surgery. A follow-up CTA showed a well-established COW with a decreased caliber of the distal right middle cerebral artery (MCA).

Fig. 1: MPR (Figs. 1a and 1d) and cVRT (Figs. 1b, 1c, 1e, and 1f) images show the comparison between prior to (Figs. 1a-1c) and after surgery (Figs. 1d–1f). A large, hypervascularized and heterogeneous mass (Fig. 1a) in the left carotid space is completely resected (Fig. 1d). In the arterial phase (Figs. 1b and 1e), the left CCA is shown to be severely encased (Fig. 1b) and is ligated along with the resection of the tumor (Fig. 1e). In the venous phase (Figs. 1c and 1f), the left IJV, EJV and multiple tortuous collaterals are shown to be displaced by, and adherent to, the mass (Fig. 1c) and are ligated as well (Fig. 1f).

CBTs are slow-growing, rare neoplasms arising from the chemoreceptor cells of the carotid bulb. Surgical excision is the treatment of choice. These tumors can pose a great technical challenge for surgeons due to their location and their hypervascularization. The evaluation of imaging features and cerebral collateral circulation is critical for the selection of treatment methods. CTA can define the size and margins of the tumor, the adherence of the tumor to the peripheral tissues and the extent of the vascularization. 

With the ultra-fast scanning technique provided by a dual source CT scanner, SOMATOM® Force, a pure arterial phase can be acquired, providing an unobscured view of arterial vasculature for an optimal evaluation. Image demonstration using cinematic volume rendering technique (cVRT) provides a better 3D perspective with improved depth and shape perceptions, enabling a lifelike demonstration.