T1 coronal pre gad MRA LCC angiogram AP

Diagnosis: Glomus vagale tumor

Glomus vagale is a paraganglioma which is seen at the carotid bifurcation extending to the skull base. A paraganglioma involving just the carotid bifurcation is a carotid body tumor. Those which arise in the jugular foramen are glomus jugulare tumors. All of these masses are located within the carotid space. Glomus tympanum is another type of paraganglioma typically located on the cochlear promontory involving Jacobsen's nerve. Patients with carotid space paragangliomas often present with a slowly growing neck mass. If there is skull base involvement, they may have pulsatile tinnitus. They are associated with pheochromocytoma and have a peak incidence between 40 and 60 years of age. They are more commonly seen in women and are multiple in 5% of patients. 1/4 of patients with multiple paragangliomas have autosomal dominant transmission.

They are intensely enhancing lesions and if they involve the jugular foramen may produce a permeative erosion of the skull base best seen on CT. On non-enhanced MR, they have been described as having a "salt and pepper" appearance due to dark flow voids which are the pepper and small foci of subacute hemorrhage which are the salt. If this pattern is present (not in this case), it is characteristic of paraganglioma.

Schwannoma may present as a carotid space mass. Minimal if any vascularity is present. They have uniform signal without flow voids. Necrosis may be present. If a schwannoma involves a skull base, the erosion of the jugular foramen is more scalloped versus the permeative appearance of a paraganglioma. Likewise, neurofibroma may present as a carotid space mass and is usually indistinguishable from schwannoma. Since the carotid space contains normal lymph nodes, metastases or lymphoma may also present as a carotid space mass.

The location of the mass combined with the clinical history and the vascularity makes glomus vagale the best diagnosis. This patient has a family history of paraganglioma. Related Cases

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