1. Enhancing hypermetabolic mass in the right jugular foramen and evidence of prior suboccipital craniotomy with reconstruction.
2. Additional enhancing hypermetabolic mass at the left carotid artery bifurcation.

Avidly enhancing masses with FDG uptake in these locations are typical of paragangliomas. These tumors of the sympathetic nervous system are often named according to their location in the head and neck:

• Glomus Tympanicum
  Presents with pulsatile tinnitus, most common middle ear tumor
• Glomus Jugulare
  Jugular foramen, pulsatile tinnitus or CN 9-11 neuropathy
• Glomus Vagale
  Rare posterolateral pharyngeal mass, possible vagal neuropathy
• Carotid Body Tumor
  Most common type, pulsatile mass at carotid bifurcation

Bilateral tumors, as in this patient with right glomus jugulare tumor and left carotid body tumor, should raise suspicion for a genetic cause:

• Succinate dehydrogenase mutations – cause of Paraganglioma Syndromes 1,3,4
• Multiple endocrine neoplasia type 2 (MEN2)
• von Hippel-Lindau (VHL)
• Neurofibromatosis type 1 (NF1)

This patient had Succinate Dehydrogenase subunit D (SDHD) mutation.

Rao AR. Radiographics 1999;19:1605-32. Boedeker CC. Head Neck 2014;36:907-16.

As with other lesions of the suprahyoid neck, MRI is generally preferred over CT for anatomic assessment. Paragangliomas are T2 hyperintense tumors with avid post-contrast enhancement. In fact, prominent vascularity within the tumor causes flow voids on MR images and a “salt and pepper” appearance.

Carotid body tumors classically separate or “splay” the internal and external carotid arteries, while vagal nerve tumors (schwannoma or glomus vagale) will displace both arteries anteriorly. Exceptions do occur.

MIBG, Octrotide, and FDG PET have all been used to image paragangliomas and pheochromocytomas. In head and neck paragangliomas, Octreotide scan has increased sensitivity (85-90%) versus MIBG (~50%).
Koopman KP, et al. J Nucl Med 2008;49:1232-7.
Muros MA, e t al. Nucl Med Commun 1998;19:735-42.

Patients with Succinate Dehydrogenase mutations are at risk for malignant paraganglioma, and FDG PET/CT is preferred for diagnosis and staging.
Timmers HJ, J Clin Oncol 2007;25:2262-9.

F18 Fluorodopa and Ga68 DOTANOC may further improve accuracy of imaging.
Fottner C, et al. J Clin Endocrinol Metab 2010;95:2800-2810.
Sharma P, et al. J Nucl Med 2013;54:841-847.