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Jugular paraganglioma

Jugular paraganglioma is a rare neuroendocrine tumor of the head and neck arising from the jugular fossa, typically presenting in adults aged 40-60 years with female predominance, often causing pulsatile tinnitus, hearing loss, or cranial nerve palsies.

Key Images

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Look For First
  • Salt and pepper appearance on T1 and T2 weighted MRI sequences from intratumoral hemorrhage and high vascularity
  • Intense, marked enhancement on T1 post-gadolinium imaging reflecting the hypervascular nature of the lesion
  • Moth-eaten irregular bone erosion pattern of the jugular fossa and jugular spine on CT
  • Flow voids indicating high vascularity within a mass at the jugular foramen
Key Image Findings
  • On MRI, jugular paragangliomas demonstrate low T1 signal, high T2 signal, and marked intense enhancement with gadolinium, reflecting their hypervascular nature.
  • The pathognomonic salt and pepper appearance results from a combination of signal representing blood products from hemorrhage or slow flow (salt) and signal voids from rapid flow through tumor vascularity (pepper) seen on both T1 and T2 sequences.
  • CT imaging reveals irregular, moth-eaten pattern erosion of the bony margins of the jugular fossa, eventually eroding the jugular spine as the tumor enlarges.
  • The Phelp sign—erosion of the caroticojugular spine between the carotid canal and jugular fossa—is a characteristic finding on CT.
  • DSA angiography demonstrates an intense tumor blush with prominent early draining veins due to intratumoral arteriovenous shunting, most commonly supplied by the ascending pharyngeal artery.
  • The tumor characteristically extends superiorly into the mastoid air cells and middle ear, medially into the Eustachian tube, and inferiorly into the infratemporal fossa.
  • Indium-111 labeled octreotide scintigraphy with SPECT shows accumulation within the tumor due to somatostatin receptors, but only reliably visualizes lesions greater than 1.5 cm in diameter.
  • CT is essential for assessing ossicular integrity and the bony labyrinth, as well as determining the extent of jugular foramen and temporal bone involvement.
Differential Diagnosis
  • Jugular schwannoma: distinguished by sharply demarcated smooth scalloped osseous margins, absence of internal flow voids, low vascularity on angiography, lack of salt and pepper appearance, and negative indium-111 octreotide scan
  • Bony metastases: hypervascular tumors such as renal cell carcinoma or thyroid cancer may mimic jugular paraganglioma but are distinguished by patient history and primary tumor imaging
  • Meningioma: typically shows different imaging characteristics and location, though can rarely occur in jugular fossa
  • High-riding or dehiscent jugular bulb: normal anatomical variation that can be distinguished by lack of mass effect, no enhancement, and normal vascular flow pattern
  • Jugular bulb thrombosis: distinguished by absence of arterial enhancement and characteristic features of thrombosis on imaging
  • Endolymphatic sac tumor: characterized by centered location in the vestibular aqueduct rather than the jugular bulb, distinguishing it from jugular paraganglioma
Discussion

Jugular paragangliomas are the most common tumors of the jugular fossa despite being rare overall, with up to 10% of patients having bilateral or multiple paragangliomas.

The clinical presentation depends on the degree of middle ear involvement, ranging from asymptomatic incidental findings to pulsatile tinnitus and hearing loss when significant middle ear involvement is present.

Multiple cranial nerve syndromes can result from tumor involvement of structures at the jugular foramen, including Vernet syndrome (CN IX, X, XI), Collet-Sicard syndrome (CN IX, X, XI, XII), and Horner syndrome (CN XII).

Surgery is the definitive treatment with cure expected after complete resection, but recurrence and local invasion occur in 40-50% of cases, requiring long-term surveillance.

Base of skull paragangliomas such as jugular paragangliomas are radiosensitive, making radiotherapy an effective treatment option for large inoperable tumors or medically frail patients, in contrast to the relative radioresistance of cervical paragangliomas.

Preoperative DSA with embolization 1-2 days prior to surgery reduces operative blood loss by occlusion of feeding vessels, but requires expertise in regional vascular anatomy to avoid complications.

Reporting Pearls

Describe the lesion as a hypervascular mass at the jugular foramen with salt and pepper signal characteristics on MRI, intense post-gadolinium enhancement, moth-eaten irregular bone erosion on CT, and specify the direction of extension (superior to mastoid air cells/middle ear, inferior to infratemporal fossa) and presence of any associated cranial nerve involvement, then recommend DSA for vascular characterization and preoperative planning.

Pitfalls
  • The salt and pepper appearance, while characteristic, is not pathognomonic and can be seen in other hypervascular lesions such as hypervascular metastases, leading to overdiagnosis if clinical context and other imaging features are not considered.
  • Smaller paragangliomas (<1.5 cm) may not demonstrate the classic salt and pepper appearance, potentially leading to underestimation of tumor vascularity and misdiagnosis as a benign lesion.
  • Confusion between terminology (glomus jugulare vs. jugular paraganglioma vs. jugulotympanic vs. tympanic paraganglioma) can lead to miscommunication about lesion location and extent; precise anatomical description of jugular foramen involvement is essential.
  • Failure to recognize erosion of the caroticojugular spine (Phelp sign) and assess the relationship to adjacent carotid artery and jugular vein on multiplanar imaging may underestimate surgical risk and impact surgical planning.
Source: Reference source

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