Non-paraganglioma tumors of the jugular foramen - Growth patterns, radiological presentation, differential diagnosis.

Objective: Most common tumors of the jugular foramen are paragangliomas. However, other lesions, also malignant, may involve the jugular foramen and mimic radiographic presentation of paragangliomas. Therefore, a correct preoperative diagnosis is crucial for best treatment planning. This study analyzes imaging characteristics of non-paraganglioma neoplasms involving the jugular foramen, with attention given to features helpful in differential diagnosis.

Study Design: A retrospective chart search.

Setting: Teritary referral university centre.

Subjects And Methods: During the years 1997-2010, 11 cases of jugular foramen tumors other than paragangliomas, with available imaging studies, were identified. Histopathology revealed: 3 schwannomas, 1 malignant schwannoma, 2 meningiomas, 1 hemangiopericytoma, 1 ependymoma, 1 endolymphatic sac carcinoma (ELST) and 2 nasopharyngeal carcinoma metastases. CT, MRI and angiography were assessed to determine tumor growth directions, bone involvement, tumor morphology and vascular composition.

Results: Schwannomas were characterized by parapharyngeal space involvement, jugular foramen expansion, preservation of cortical margins, irregular contrast enhancement. Meningiomas presented diffuse bone infiltration, sclerotic changes, erosion of the cortical bone. Ependymoma showed diffuse skull base infiltration, permeative erosion, heterogeneity, abundant vascularization. Hemangiopericytoma radiologically imitated paraganglioma. ELST showed permeative/geographic bony destruction, heterogeneity, intratumoral bony fragments. Metastases were lytic, solid lesions characterized by circumferential growth, internal carotid artery encasement and stenosis.

Conclusions: A combination of certain radiological features including tumor epicenter, growth vectors, skull base infiltration, bony changes and tumor morphology help establish correct preoperative diagnosis and differentiate less common jugular foramen tumors, from most common paragangliomas. Hemangiopericytoma may radiologically mimic paraganglioma.