Cardiovascular Radiology

Findings reveal bilateral hyperdense enhancing mass lesions with feeder vessels, at the carotid bifurcation bilaterally. 

Diagnosis
Carotid Body Tumor 

Discussion 

Introduction

Paragangliomas are tumors that arise from the branchiomeric paraganglia which are distributed from the skull base down to the aortic arch. These neoplasms are most commonly seen arising from the carotid body, the paraganglionic tissue located at the carotid bifurcation. Although these tumors were originally termed chemodectomas, the term carotid body tumor (CBT) has emerged as the most popular description for those located at the carotid bifurcation.

Other common sites for paragangliomas to arise are from the paraganglia of the tympanic, jugular, and the high vagal regions. The nomenclature most commonly used for these tumors are glomus tympanicum, glomus jugulare, and glomus vagale.

The differential diagnosis of an incidentally observed non-tender antero-lateral neck mass includes metastatic lymph nodes, carotid body aneurysm, salivary gland tumor, branchial cleft cyst, and thyroid and neurogenic tumors. Although arteriography is considered mandatory and remains the gold standard for diagnosis, noninvasive imaging studies are frequently adequate for workup of suspected CBTs.

Imaging

CT demonstrates a solid mass that shows homogenous enhancement on intravenous contrast administration. The presence of uniform contrast enhancement and large feeding vessels into the tumor is not seen in lymph node masses and schwannomas. The incorporation of large feeding vessels is typical of carotid body paragangliomas whereas schwannomas tend to displace the adjacent vessels. The medical displacement of the internal carotid artery is considered to be specific for tumors of vagal origin, whether they are schwannomas or paragangliomas

Arteriograph: the gold standard for diagnosing CBTs, this study demonstrates a pathognomonic tumor blush as well as the feeding vessels of the tumor; and is an excellent screening tool for concomitant paragangliomas.

MR: non-contrast T1W images demonstrate a heterogeneous mass with isointense signal intensity at the carotid artery bifurcation with multiple serpentine areas of low signal intensity representing flow voids throughout the mass. On T2W images the tumor shows hyperintense signal intensity. On intravenous gadolinium DTPA contrast administration, the tumor enhances intensely.

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