Jugular fossa masses
Jugular fossa masses comprise a range of pathological lesions that arise from or extend into the jugular fossa in the skull base. Although not a common location for tumors it is not unusual for jugular fossa lesions to be discovered incidentally on cross-sectional imaging.
Although the jugular foramen is technically an anatomically distinct entity which connects the jugular fossa to the posterior fossa, both contain the same neurovascular structures and lesions present similarly. As the differential for lesions arising here are the same, for the purposes of this article the terms jugular fossa and jugular foramen will be used interchangeably.
Although the exact underlying pathology varies most jugular fossa tumors are slow growing and can cause symptoms by compressing the nerves that lie within the fossa. Symptoms can include:
- loss of taste from the posterior one-third of the tongue
- glossopharyngeal nerve palsy (CN IX)
- vocal cord paralysis and absent gag reflex
- vagus nerve palsy (CN X)
- weakness of the trapezius and sternocleidomastoid muscles
- accessory nerve palsy (CN XI)
When there is unilateral palsy of the 9-11 cranial nerves this is termed as jugular foramen syndrome.
However, the most common symptoms tend to arise from expansion into the middle ear:
Involvement of the inner ear can lead to vertigo and sensorineural hearing loss.
Symptoms of raised intracranial compression can develop if there is significant intracranial extension of the underlying tumor.
The most common lesion seen involving the jugular fossa is a glomus jugulare paraganglioma followed by schwannomas and meningiomas.
Jugular fossa masses can broadly be classified as extrinsic or intrinsic.
Occasionally, pseudotumors can arise as a result of:
- CSF leak due to trauma
- jugular bulb flow variation or vascular anatomic variant such as normal asymmetry, high riding jugular bulb, or jugular bulb diverticulum
Intrinsic masses arise from the structures that traverse the jugular fossa:
- primitive neuroectodermal tumor
- metastatic malignant tumors or lymphoma
Extrinsic masses arise from the surrounding tissues around the jugular fossa and extend into it:
- glial cell tumors
- inflammatory lesions
- temporal bone tumors
- primary cholesteatoma
- epidermoid tumors
- choroid plexus papilloma
While contrast MRI is better at defining the nature of jugular fossa lesions, CT is superior in assessing if there is any involvement of the adjacent bony structures.