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Neuroradiology Case of
the Week
Case 177
Edward Lin, MD and Per-Lennart Westesson, MD, PhD, DDS
Clinical
Presentation: This patient is a 65-year-old female with dysphagia and weight loss.
Radiological Findings:
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| Figure 1. Three selected post contrast axial computed tomography sections demonstrate a heterogeneously enhancing lobulated mass splaying the right internal and external carotid arteries at the bifurcation (A) and (B), and a second mass more superiorly in between the left internal carotid artery and internal jugular vein (C). |
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| Figure 2. Selected axial T1 pre (A) and post-contrast with fat suppression (B) MR images of the neck in a different patient demonstrate a large lobulated mass, in between the internal and external carotid arteries, with decreased T1 signal, avid heterogeneous enhancement and large flow voids representing vessels in the periphery of the mass. |
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Figure 3. Selected coronal T1 pre (A) and post contrast with fat suppression (B) weighted MR images of the same patient as in Figure 2 demonstrate heterogeneous decreased T1 and increased T2 signal of the carotid body mass, with large flow voids within the mass. |
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| Figure 4. Right carotid artery angiogram in the same patient as Figures 2 and 3 demonstrate early arterial blush (A) of carotid body mass in between the internal and external carotid branches and intense enhancement at the peak of arterial phase (B). |
Diagnosis: Carotid body paraganglioma
Discussion: Carotid body paragangliomas (CBP) are benign vascular tumors arising in the glomus bodies (paraganglia) of the carotid body at the bifurcation of the external and internal carotid arteries. Glomus bodies are composed of chemoreceptor cells, which are derived from neural crest cells. They are also found in the temporal bone, jugular foramen and upper carotid space, as noted in the patient discussed above.
CBP may occur at all ages, but are more common in the 4th and 5th decades. They may be sporadic or familial. Multicentric lesions occur in 50-90% of familial cases, and 2-10% in non-familial cases. CBP is associated with thyroid carcinomas and MEN syndromes. Of note, CBP are more frequent in populations at high altitude.
Patients typically present with a painless pulsatile mass in the angle of the mandible. Twenty percent have vagal and less often hypoglossal neuropathy.
Ultrasound evaluation reveals a solid inhomogeneous mass with increased vascularity on Color Doppler.
CT imaging demonstrates a lobular soft tissue mass splaying the ICA and ECA at the bifurcation, extending cephalad. CBP rapidly enhance homogeneously on post contrast images.
MR imaging shows a mass isointense with muscle, slightly hyperintense on T2 weighted images, and intense enhancement on post-contrast images. If larger than 1.5 cm, CBP tumors may infrequently exhibit a “salt and pepper appearance.” The “salt” corresponds to subacute hemorrhage which manifests as high signal foci. The “pepper” corresponds to flow voids due to the high vascularity of the tumor.
Angiography findings reveal a prolonged, intense tumor blush with early arteriovenous shunting. The pharyngeal artery provides the main feeding branch to the tumor.
Therapy entails surgical resection, with little complications seen in CBP less than 5 cm. Permanent vagal and hypoglossal neuropathy may occur with tumors greater than 5 cm.
This patient has not undergone surgery in light of cardiac failure. The patient’s dysphagia and weight loss may or may not be related to the carotid body paragangliomas.
References:
- Harnsberger R, et al. Diagnostic Imaging: Head and Neck. WB Saunders, 2004.
- Kerr JT, Eusterman VD, Yoest SM, Andersen CA. Pitfalls in imaging: differentiating intravagal and carotid body paragangliomas. Ear Nose Throat J. 2005 Jun;84(6):348-50. [Medline]
- vanden Berg R. Imaging and management of head and neck paragangliomas. Eur Radiol. 2005 Jul;15(7):1310-8. [Medline]
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