Neuroradiology

Paraganglioma

tumour originating from extra-adrenal neuroendocrine tissues, collected in paraganglia; paraganglia have a chemoreceptor function and are located near nerves and vessels.

The most common sites of paragangliomas of the head and neck are:

the carotid body at the common carotid artery bifurcation;

the jugular foramen, along the vagus nerve; and

within the middle ear.

The terms glomus tumour and chemodectoma are used as synonyms for paraganglioma.

The clinical manifestation of a carotid body tumour is a nontender, insidiously enlarging lateral neck mass in an otherwise asymptomatic patient. The vagal paraganglioma manifests as a slowly growing, painless lateral neck mass, most commonly located behind the angle of the mandible. Glomus jugulare tympanicum tumours cause pulsatile tinnitus and may be seen as a retrotympanic vascular mass. Cranial nerve palsies occur late in the course of the disease.

Both CT (Fig.1) and MR depict these highly vascular, soft-tissue masses and selective angiography characterizes the feeding pedicles and vascular structure.

At CT the tumour appears as a well-defined soft tissue isodense mass, located either within the carotid space, or in the jugular foramen which is usually enlarged or within the middle ear. Different degrees of associated petrous bone erosion, infiltration and destruction are observed. At MR paragangliomas usually show T1 hypointensity and T2 hyperintensity, with multiple serpentine and punctate areas of signal void. Intense enhancement is noted following intravenous injection of contrast.

The typical angiographic appearance is that of a hypervascular mass with enlarged feeding arteries, intense tumour blush and early draining veins. Carotid body tumours typically cause splaying of the external and internal carotid arteries. The most common feeding vessel for head and neck paragangliomas is the ascending pharyngeal artery.

GS

To view high resolution images,
please register first.

Click  here to register.

Already registered? Enter your e-mail in the window below.
Re-register

Fig.1

a. Angio-MR of the carotid bifurcation. Both internal and external carotid arteries are displaced around a paraganglioma of the carotid body. b. Common carotid angiogram. Marked blush of the tumour, fed by the external carotid artery. c. Selective injection of the external carotid artery; the tumour is fed by branches of the ascending pharyngeal artery. d. Superselective injection of a feeding branch to the tumour. e. Injection of the same branch following embolization with polyvinyl alcohol (PVA) particles. Opacification of the vertebral artery through occipito-vertebral anastomosis.
Paraganglioma, Fig.1 (a)
Paraganglioma, Fig.1 (b)
Paraganglioma, Fig.1 (c)
Paraganglioma, Fig.1 (d)
Paraganglioma, Fig.1 (e)