Paragangliomas of the head and neck
Core idea
Slow growing, but locally destructive neuroendocrine tumours arising from parasympathetic paraganglia (neural crest origin) in the classic head and neck locations, usually non–catecholamine-secreting but highly vascular, seen as intense enhancement and “salt-and-pepper” MRI.
Genetics & syndromes
- H&N PG particularly often hereditary (often quoted ≥50%).
- Key genes:
- SDHX (SDHB, SDHC, SDHD, SDHAF2) – “paraganglioma syndromes”.
- SDHD, SDHAF2 → often multiple head and neck paragangliomas.
- SDHB → higher risk of metastatic disease (esp. extra-adrenal trunk/abdomen).
- ± VHL, NF1, RET (MEN2) mainly in adrenal phaeochromocytoma context.
- SDHX (SDHB, SDHC, SDHD, SDHAF2) – “paraganglioma syndromes”.
Imaging implication
Multiple lesions? Young patient? → think SDH mutation and screen whole paraganglionic axis (skull base to pelvis).
Trivia
| Head & neck PG | Thoracoabdominal PG |
|---|---|
| Parasympathetic origin | Sympathetic origin |
| Usually non-functional (no systemic catecholamine symptoms) | Often functional/pheochromocytoma-like |
- PG is usually slow-growing but can metastasise; malignancy defined by nodal/distant spread (lung, bone), not histology.
- Risk is higher in SDHB-mutation carriers.
Clinical features
- Age: usually middle-aged adults; can present younger if hereditary.
- Sex: slight female predominance overall.
- Generally slow-growing but locally aggressive.
Symptoms
Patients usually present with mass or symptoms according to local tumour destruction.
- Carotid body tumour (at carotid bifurcation)
- Painless lateral neck mass at angle of mandible.
- Sometimes pulsatile, ± bruit.
- Large lesions → lower cranial nerve palsies (IX–XII) → dysphagia, hoarseness.
- Glomus jugulare / jugulotympanic (in jugular foramen/extending to middle ear)
- Pulsatile tinnitus, conductive hearing loss, aural fullness.
- Lower cranial nerve palsies (IX, X, XI ± XII).
- Retrotympanic red mass on otoscopy (jugulotympanic).
- Glomus tympanicum (at middle ear cavity)
- Smaller retrotympanic red mass.
- Conductive hearing loss, pulsatile tinnitus.
- Confined to middle ear, jugular foramen intact.
- Glomus vagale (along vagus nerve in high carotid space)
- High neck mass in carotid space.
- Vagal palsy → hoarseness, cough, dysphagia.
- ± Other lower CN involvement, Horner if sympathetic chain involved.
Laryngeal, nasopharyngeal, and other skull-base paragangliomas can happen but are way less common.
Systemic catecholamine symptoms are rare in head & neck paragangliomas.
Imaging
Signature imaging appearance
Hypervascular soft-tissue mass with:
- Intense, often early enhancement.
- “Salt-and-pepper” on MRI (flow voids + slow-flow/haemorrhage).
- Location-specific vessel displacement patterns.
CT
- Soft tissue:
- Strong enhancement.
- Lobulated margins common.
- Bone:
- Jugular foramen lesions → bone destruction/widening (glomus jugulare).
- Carotid-space lesions → usually no bone erosion unless very large.
MRI
- T1: iso–hypointense to muscle.
- T2: hyperintense; often heterogenous.
- Salt-and-pepper:
- Pepper = flow voids from high-flow vessels.
- Salt = high-signal foci (slow flow, haemorrhage).
- However, very small PGs may just look uniformly bright.
- Avid post-contrast enhancement.
Angiography (DSA)
- Intense tumour blush with early draining veins.
- Useful for:
- Confirming hypervascular nature.
- Mapping arterial feeders.
- Pre-operative embolisation planning.
- Typical feeders: ascending pharyngeal, occipital, posterior auricular branches of ECA (esp. for CB/jugulotympanic).
Nuclear medicine
- Somatostatin receptor imaging:
- 68Ga-DOTATATE PET/CT – excellent for detection of multifocal disease and metastases.
- 111In-octreotide (historical).
- MIBG: more for functional/adrenergic lesions (adrenal pheo, sympathetic paraganglioma).
- FDG PET: can be helpful in SDHB-mutant and more aggressive/metastatic disease.
Location-specific features
| Lesion | Key displacement / features |
|---|---|
| Carotid body tumour | Splays ICA & ECA (“lyre sign”) |
| Glomus vagale | Mass between ICA & IJV → ICA anteromedial, IJV posterolateral |
| Glomus jugulare | Enlarged/destructed jugular foramen, may extend to middle ear, mastoid, posterior fossa |
| Glomus tympanicum | Small enhancing mass on cochlear promontory; jugular foramen intact |
Management overview
-
Work-up
- Full head & neck imaging (CT + MRI).
- Look for multiplicity (other paragangliomas).
- Consider chest/abdo/pelvis imaging for extra lesions / pheo.
- Check catecholamines/metanephrines before surgery or embolisation, especially if there are any systemic symptoms or extra-adrenal lesions, to avoid hypertensive crisis.
-
Treatment
Depends on size, symptoms, age, comorbidities, genetic status.- Surgery: for accessible or symptomatic lesions.
- ± Pre-operative embolization (esp. glomus jugulare).
- Radiotherapy / stereotactic radiosurgery: common for skull-base lesions, older or high-risk surgical patients.
- Observation (“wait and scan”): for small, minimally symptomatic lesions in elderly or high-risk cases.
- Surgery: for accessible or symptomatic lesions.
Management pitfall
Biopsy is generally avoided because these are highly vascular → risk of significant bleeding. Diagnosis is usually imaging + clinical + nuclear medicine ± genetics.
Summary
- Head & neck paragangliomas = parasympathetic, usually non-functional, but very vascular.
- Classic imaging: salt-and-pepper MRI, avid enhancement, location-specific vessel displacement.
- Carotid body tumour → carotid bifurcation, splaying ICA/ECA (“lyre sign”).
- Glomus jugulare → centred on jugular foramen with bone erosion, ± middle-ear extension.
- Glomus tympanicum → small middle-ear mass on cochlear promontory, jugular foramen intact.
- Glomus vagale → high carotid space, mass between ICA & IJV, hoarseness from CN X palsy.
- Always consider SDH mutation and multifocal disease → think whole-axis imaging + genetics.
- Avoid biopsy
