Glomus Jugulare Tumours

Synonyms: chemodectomas, nonchromaffin paragangliomas

These are rare, slow-growing, very vascular tumours of a group called paragangliomas. They are derived from glomera jugulare (or glomus bodies) which themselves are derived from neural tissue and arise within the jugular foramen of the temporal bone. They occur at such sites as the carotid body, the vagus nerve and the middle ear. Much more rarely, they may be found at other sites including the periaortic area, trachea, larynx, mandible, nose, ciliary ganglion and fallopian canal.

These tumours tend to be benign and slow growing but they can be locally aggressive, this is important because of their proximity to the lower cranial nerves and to some major vascular structures.² The tumours may also extend to involve the middle ear. Only about 4% metastasise. Metastases have been found in the lung, lymph nodes, liver, vertebrae, ribs, and spleen. The base of the skull is eroded with extension to the mastoid and occipital bones. Between 2 and 4% of tumours produce catecholamines, noradrenaline or dopamine resulting in a clinical picture similar to phaeochromocytoma with hypertension and tachycardia. Tumours may also produce somatostatin, vasoactive intestinal polypeptide (VIP) and calcitonin.

They sometimes run in families in an autosomal dominant fashion with incomplete penetrance.³ The gene responsible for hereditary paragangliomas is on band 11q23.⁴

Because of the insidious onset of symptoms, these tumours often go unnoticed and delay in diagnosis is frequent. They may therefore be very large at the time of diagnosis.

• Although this is a rare tumour (the annual incidence is around 1 in 1.3 million people per year),⁵ it is the most common tumour of the middle ear and the second most common tumour of the temporal bone.¹
• They tend to present between 40 and 70 years of age (range: 6 months to 88 years)
• There is a female preponderance of between 3 and 6:1.
• It ore commonly occurs on the left side; multicentric tumours are found in 3-10% of sporadic cases and in 25-50% of familial cases.¹

Symptoms

• The commonest symptoms are deafness and a pulsatile tinnitus.
• There may be an associated vertigo.
• Pain in the ear is uncommon.
• If the jugular foramen syndrome develops (paresis of cranial nerves IX to XI), there may also be complaints of hoarseness and symptoms associated with dysphagia.
• Less commonly, these tumours produce facial nerve palsy,⁶ hypoglossal nerve palsy or Horner's syndrome.
• Ataxia and brainstem symptoms may also develop.
• Headaches can occur as a result of intracranial extension.

Signs

• The hearing loss may be conductive or sensori-neural.⁷ Vertigo is associated with the latter.
• There may be otorrhoea, haemorrhage, bruit and the presence of a middle ear mass: otoscopic examination reveals a characteristic, pulsatile, reddish-blue tumour behind the tympanic membrane but this may represent the tip of the iceberg of this tumour.
• If the jugular foramen syndrome develops, look for evidence of paresis of cranial nerves IX to XI. It is pathognomonic for this tumour but it usually follows a year after the initial symptoms of hearing loss and pulsatile tinnitus.
• Look for evidence of intracranial extension, manifested by signs associated with hydrocephalus and elevated intracranial pressure.
• Involvement of the dural sinuses mimics sinus thrombosis.

A small number of patients present primarily with a phaeochromocytoma-like picture e.g. perspiration, pallor, nausea, hypertension and tachycardia.

Other tumours that have been reported in association with glomus jugulare tumours are:

• Phaeochromocytoma
• Parathyroid adenoma
• Thyroid carcinoma
• Neurofibromatosis-1

• Audiometry will show a mixture of sensori-neural and conductive loss, the former more marked as the tumour expands.
• Plain skull x-rays may show evidence of the lesion with enlargement of the lateral jugular foramen and fossa.
• The best imaging technique is CT combined with MRI with DTPA enhancement.
• Arteriography may be required before resection of large tumours.
• There should be screening for catecholamines.

The list is long and includes:

• Otitis media
• Chordoma
• Histiocytosis X
• Meningioma
• Schwannoma
• Neurofibroma
• Primary or metastatic carcinoma
• Cholesteatoma
• Aneurysm
• Lymphoma

The most commonly used classifications are Glasscock-Jackson and Fisch. The Fisch classification describes four stages of tumour development:

• A - tumour limited to the middle ear cleft (glomus tympanicum)
• B - tumour limited to the tympanomastoid area with no infralabyrinthine compartment involvement
• C - tumour involving the infralabyrinthine compartment of the temporal bone and extending into the petrous apex
  • C1 - tumour with limited involvement of the vertical portion of the carotid canal
  • C2 - tumour invading the vertical portion of the carotid canal
  • C3 - tumour invasion of the horizontal portion of the carotid canal
• D - tumour with intracranial extension
  • D1 - tumour with an intracranial extension less than 2 cm in diameter
  • D2 - tumour with an intracranial extension greater than 2 cm in diameter.

Options

• Surgical resection is the treatment of choice for young, otherwise healthy patients with functional cranial nerve deficits and is a relatively simple procedure in early tumours.⁸
• It becomes more complex and is better avoided in older and more frail patients, especially if there is significant extension.
• As the tumour grows so slowly, simply watching and waiting with serial imaging may suffice in the elderly.
• Embolisation, radiotherapy, gamma knife radiosurgery and intratumoral injection of cyanoacrylate glue are other options.⁹
• Genetic screening is appropriate for individuals with a positive family history.⁸

Surgery

Alpha and beta blockers may be required for some weeks before treatment if catecholamine production causes high and labile blood pressure. The surgical approach may depend on the Fisch stage of the tumour:

• Type A can be excised by a transmeatal or perimeatal approach.
• Type B need an extended posterior tympanotomy.
• Type C need radical resection through a combined transmastoid-infratemporal or transtemporal-infratemporal approach preceded by external carotid artery embolisation. Surgery is a therapeutic success in about 90% of patients.
• Large type D need to be treated with a combined ENT and neurosurgical approach. It may be possible to remove the entire tumour. Incomplete resection should be followed by radiation and follow-up MRI and CT scans. Megavoltage radiotherapy gives very good results.¹⁰
• More recently, more conservative surgery has been combined with post-operative gamma knife radiosurgery which has enabled tissue diagnosis and improvement of symptoms without some of the serious complications of more extensive surgery (see below).²

Surgery can lead to damage of the cranial nerves.⁵ Other complications include bleeding, cerebrospinal fluid (CSF) leak, meningitis, uncontrollable hypotension/hypertension and tumour regrowth.¹ Death can also occur.

Glomus jugulare tumours tend to grow slowly with only a small proportion metastasising. The associated cranial nerve palsies are more cosmetic than debilitating. The first case was diagnosed in 1945 and died in 1987.¹ The overall mortality rate is 8.7% with worse figures for radiotherapy (8.7%) than surgery (2.5%) although radiotherapy patients are higher risk patients at the outset. Even 20 years after treatment, the survival rate is 94% and 77% of patients remain symptom free.¹¹