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A young adult nonsmoker patient with a history of asthma presented with a palpable mass on the left side of the neck that had been present for several months, reportedly unchanged. The patient had been treated presumptively for infection with antibiotics, with no improvement. No fever, odynophagia, dysphagia, otalgia, or other constitutional symptoms were reported. Physical examination findings demonstrated a palpable, soft, nontender left level II/III neck mass. Clinical examination findings of the thyroid and upper aerodigestive tract were unremarkable. Contrast-enhanced neck computed tomography (CT) showed a large avidly enhancing mass centered at the left carotid bifurcation splaying the internal and external carotid arteries and extending cranially along the cervical internal carotid artery. The left internal jugular vein was displaced posteriorly. There was also a smaller mass with similar appearance at the right carotid bifurcation (Figure 1A). Contrast-enhanced abdominal CT showed several enhancing masses in the liver (not shown). Based on CT findings, gallium Ga 68 (68Ga) dotatate positron emission tomography (PET)/magnetic resonance imaging (MRI) was performed; results demonstrated intense radiotracer avidity in bilateral carotid space masses, hepatic masses, and numerous CT occult osseous lesions (Figure 1B).
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B. Metastatic carotid body tumors
Head and neck paragangliomas (HNPs) are hypervascular neuroendocrine neoplasms arising from chromaffin cells of parasympathetic paraganglia in the head and neck. Accurate imaging diagnosis of HNPs is important given their hypervascularity.1 Radiologically, HNPs occur in characteristic locations of paraganglia, are well circumscribed, and avidly enhance with rapid washout on CT or MRI. Small (<2 cm) HNPs enhance homogeneously, whereas larger HNPs may enhance heterogeneously. Some tumors have a salt-and-pepper appearance on T2-weighted images, representing intratumoral hyperintense foci of slow-flow and hypointense flow voids.2
Most paragangliomas are benign. Carotid body tumor (CBT) is the most common HNP, arising from the paraganglionic cell near the carotid bifurcation and classically splays the carotid bifurcation (Figure 2). Paragangliomas are associated with genetic defects that can be sporadic or familial, with autosomal dominant inheritance. The familial form has a higher incidence of multifocality, particularly CBTs.1,2
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Corresponding Author: Tanya J. Rath, MD, Neuroradiology Section, Department of Radiology, Mayo Clinic Arizona, 5777 E Mayo Blvd, Phoenix, AZ 85054 (firstname.lastname@example.org).
Published Online: July 9, 2020. doi:10.1001/jamaoto.2020.1107
Conflict of Interest Disclosures: None reported.
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