jugular schwannoma

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Jugular foramen schwannomas are a rare type of intracranial schwannoma that presents as a jugular fossa mass involving the jugular foramen.

Epidemiology

In those without neurofibromatosis type 2 (NF2), they tend to present between the 3 to 6 decades of life. There is a recognized female predilection . The tumors can have a wide variety of clinical presentations.

Pathology

They can arise from cranial nerves IX, X or XI, with IX being the most common .

Associations

neurofibromatosis type 2 (NF2): particularly if bilateral

Radiographic features

CT

usually well-demarcated
tend to be iso to hypoattenuating to brain parenchyma
may show expansion and remodeling of the affected jugular foramen
may have a characteristic dumbbell configuration

MRI

Signal characteristics are those of a schwannoma:

T1: typically low signal
T2: typically high signal
- cystic degeneration may be seen in larger tumors
T1 C+ (Gd)
- smaller lesions demonstrate intense homogeneous enhancement
- larger lesions tend to have heterogeneous enhancement

Treatment and prognosis

As with most schwannomas, they tend to be slow-growing tumors. Surgical resection is often the treatment of choice.

Differential diagnosis

For a full list of differentials see the article on jugular fossa masses. Considerations in this location include:

paraganglioma: glomus jugulare tumor
- “salt and pepper” appearance on MRI with intense contrast enhancement and multiple small flow voids
  - vascular schwannomas may have peripheral flow voids but should not have internal flow voids
- if large, irregular erosion of the margin of the jugular foramen, with decalcification or destruction of the surrounding bone
- possible invasion of jugular bulb/vein with intraluminal growth (compared to compression by schwannomas)
meningioma around the jugular foramen
metastatic malignant tumors or lymphoma
- may be indistinguishable from schwannoma when involving jugular foramen
- most likely destruction of surrounding bone, with less sharply marked borders